From 4f738adba30a7cfc006f605707e7aee847ffefa0 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Sun, 18 Mar 2018 12:57:10 -0700 Subject: bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data This implements a BPF ULP layer to allow policy enforcement and monitoring at the socket layer. In order to support this a new program type BPF_PROG_TYPE_SK_MSG is used to run the policy at the sendmsg/sendpage hook. To attach the policy to sockets a sockmap is used with a new program attach type BPF_SK_MSG_VERDICT. Similar to previous sockmap usages when a sock is added to a sockmap, via a map update, if the map contains a BPF_SK_MSG_VERDICT program type attached then the BPF ULP layer is created on the socket and the attached BPF_PROG_TYPE_SK_MSG program is run for every msg in sendmsg case and page/offset in sendpage case. BPF_PROG_TYPE_SK_MSG Semantics/API: BPF_PROG_TYPE_SK_MSG supports only two return codes SK_PASS and SK_DROP. Returning SK_DROP free's the copied data in the sendmsg case and in the sendpage case leaves the data untouched. Both cases return -EACESS to the user. Returning SK_PASS will allow the msg to be sent. In the sendmsg case data is copied into kernel space buffers before running the BPF program. The kernel space buffers are stored in a scatterlist object where each element is a kernel memory buffer. Some effort is made to coalesce data from the sendmsg call here. For example a sendmsg call with many one byte iov entries will likely be pushed into a single entry. The BPF program is run with data pointers (start/end) pointing to the first sg element. In the sendpage case data is not copied. We opt not to copy the data by default here, because the BPF infrastructure does not know what bytes will be needed nor when they will be needed. So copying all bytes may be wasteful. Because of this the initial start/end data pointers are (0,0). Meaning no data can be read or written. This avoids reading data that may be modified by the user. A new helper is added later in this series if reading and writing the data is needed. The helper call will do a copy by default so that the page is exclusively owned by the BPF call. The verdict from the BPF_PROG_TYPE_SK_MSG applies to the entire msg in the sendmsg() case and the entire page/offset in the sendpage case. This avoids ambiguity on how to handle mixed return codes in the sendmsg case. Again a helper is added later in the series if a verdict needs to apply to multiple system calls and/or only a subpart of the currently being processed message. The helper msg_redirect_map() can be used to select the socket to send the data on. This is used similar to existing redirect use cases. This allows policy to redirect msgs. Pseudo code simple example: The basic logic to attach a program to a socket is as follows, // load the programs bpf_prog_load(SOCKMAP_TCP_MSG_PROG, BPF_PROG_TYPE_SK_MSG, &obj, &msg_prog); // lookup the sockmap bpf_map_msg = bpf_object__find_map_by_name(obj, "my_sock_map"); // get fd for sockmap map_fd_msg = bpf_map__fd(bpf_map_msg); // attach program to sockmap bpf_prog_attach(msg_prog, map_fd_msg, BPF_SK_MSG_VERDICT, 0); Adding sockets to the map is done in the normal way, // Add a socket 'fd' to sockmap at location 'i' bpf_map_update_elem(map_fd_msg, &i, fd, BPF_ANY); After the above any socket attached to "my_sock_map", in this case 'fd', will run the BPF msg verdict program (msg_prog) on every sendmsg and sendpage system call. For a complete example see BPF selftests or sockmap samples. Implementation notes: It seemed the simplest, to me at least, to use a refcnt to ensure psock is not lost across the sendmsg copy into the sg, the bpf program running on the data in sg_data, and the final pass to the TCP stack. Some performance testing may show a better method to do this and avoid the refcnt cost, but for now use the simpler method. Another item that will come after basic support is in place is supporting MSG_MORE flag. At the moment we call sendpages even if the MSG_MORE flag is set. An enhancement would be to collect the pages into a larger scatterlist and pass down the stack. Notice that bpf_tcp_sendmsg() could support this with some additional state saved across sendmsg calls. I built the code to support this without having to do refactoring work. Other features TBD include ZEROCOPY and the TCP_RECV_QUEUE/TCP_NO_QUEUE support. This will follow initial series shortly. Future work could improve size limits on the scatterlist rings used here. Currently, we use MAX_SKB_FRAGS simply because this was being used already in the TLS case. Future work could extend the kernel sk APIs to tune this depending on workload. This is a trade-off between memory usage and throughput performance. Signed-off-by: John Fastabend Acked-by: David S. Miller Acked-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- kernel/bpf/syscall.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'kernel/bpf/syscall.c') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index e24aa3241387..3aeb4ea2a93a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1315,7 +1315,8 @@ static int bpf_obj_get(const union bpf_attr *attr) #define BPF_PROG_ATTACH_LAST_FIELD attach_flags -static int sockmap_get_from_fd(const union bpf_attr *attr, bool attach) +static int sockmap_get_from_fd(const union bpf_attr *attr, + int type, bool attach) { struct bpf_prog *prog = NULL; int ufd = attr->target_fd; @@ -1329,8 +1330,7 @@ static int sockmap_get_from_fd(const union bpf_attr *attr, bool attach) return PTR_ERR(map); if (attach) { - prog = bpf_prog_get_type(attr->attach_bpf_fd, - BPF_PROG_TYPE_SK_SKB); + prog = bpf_prog_get_type(attr->attach_bpf_fd, type); if (IS_ERR(prog)) { fdput(f); return PTR_ERR(prog); @@ -1382,9 +1382,11 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_CGROUP_DEVICE: ptype = BPF_PROG_TYPE_CGROUP_DEVICE; break; + case BPF_SK_MSG_VERDICT: + return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_MSG, true); case BPF_SK_SKB_STREAM_PARSER: case BPF_SK_SKB_STREAM_VERDICT: - return sockmap_get_from_fd(attr, true); + return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, true); default: return -EINVAL; } @@ -1437,9 +1439,11 @@ static int bpf_prog_detach(const union bpf_attr *attr) case BPF_CGROUP_DEVICE: ptype = BPF_PROG_TYPE_CGROUP_DEVICE; break; + case BPF_SK_MSG_VERDICT: + return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_MSG, false); case BPF_SK_SKB_STREAM_PARSER: case BPF_SK_SKB_STREAM_VERDICT: - return sockmap_get_from_fd(attr, false); + return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, false); default: return -EINVAL; } -- cgit v1.2.3 From b76354cdfefb68bc017065850a34d486887a4f7b Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Tue, 27 Mar 2018 11:53:21 -0700 Subject: bpf: follow idr code convention Generally we do a preload before doing idr allocation. This also help improve the allocation success rate in memory pressure. Cc: Daniel Borkmann Cc: Alexei Starovoitov Signed-off-by: Shaohua Li Signed-off-by: Daniel Borkmann --- kernel/bpf/syscall.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/bpf/syscall.c') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index dd172ee16716..77d45bd9f507 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -203,11 +203,13 @@ static int bpf_map_alloc_id(struct bpf_map *map) { int id; + idr_preload(GFP_KERNEL); spin_lock_bh(&map_idr_lock); id = idr_alloc_cyclic(&map_idr, map, 1, INT_MAX, GFP_ATOMIC); if (id > 0) map->id = id; spin_unlock_bh(&map_idr_lock); + idr_preload_end(); if (WARN_ON_ONCE(!id)) return -ENOSPC; @@ -940,11 +942,13 @@ static int bpf_prog_alloc_id(struct bpf_prog *prog) { int id; + idr_preload(GFP_KERNEL); spin_lock_bh(&prog_idr_lock); id = idr_alloc_cyclic(&prog_idr, prog, 1, INT_MAX, GFP_ATOMIC); if (id > 0) prog->aux->id = id; spin_unlock_bh(&prog_idr_lock); + idr_preload_end(); /* id is in [1, INT_MAX) */ if (WARN_ON_ONCE(!id)) -- cgit v1.2.3 From c4f6699dfcb8558d138fe838f741b2c10f416cf9 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 28 Mar 2018 12:05:37 -0700 Subject: bpf: introduce BPF_RAW_TRACEPOINT Introduce BPF_PROG_TYPE_RAW_TRACEPOINT bpf program type to access kernel internal arguments of the tracepoints in their raw form. >From bpf program point of view the access to the arguments look like: struct bpf_raw_tracepoint_args { __u64 args[0]; }; int bpf_prog(struct bpf_raw_tracepoint_args *ctx) { // program can read args[N] where N depends on tracepoint // and statically verified at program load+attach time } kprobe+bpf infrastructure allows programs access function arguments. This feature allows programs access raw tracepoint arguments. Similar to proposed 'dynamic ftrace events' there are no abi guarantees to what the tracepoints arguments are and what their meaning is. The program needs to type cast args properly and use bpf_probe_read() helper to access struct fields when argument is a pointer. For every tracepoint __bpf_trace_##call function is prepared. In assembler it looks like: (gdb) disassemble __bpf_trace_xdp_exception Dump of assembler code for function __bpf_trace_xdp_exception: 0xffffffff81132080 <+0>: mov %ecx,%ecx 0xffffffff81132082 <+2>: jmpq 0xffffffff811231f0 where TRACE_EVENT(xdp_exception, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, u32 act), The above assembler snippet is casting 32-bit 'act' field into 'u64' to pass into bpf_trace_run3(), while 'dev' and 'xdp' args are passed as-is. All of ~500 of __bpf_trace_*() functions are only 5-10 byte long and in total this approach adds 7k bytes to .text. This approach gives the lowest possible overhead while calling trace_xdp_exception() from kernel C code and transitioning into bpf land. Since tracepoint+bpf are used at speeds of 1M+ events per second this is valuable optimization. The new BPF_RAW_TRACEPOINT_OPEN sys_bpf command is introduced that returns anon_inode FD of 'bpf-raw-tracepoint' object. The user space looks like: // load bpf prog with BPF_PROG_TYPE_RAW_TRACEPOINT type prog_fd = bpf_prog_load(...); // receive anon_inode fd for given bpf_raw_tracepoint with prog attached raw_tp_fd = bpf_raw_tracepoint_open("xdp_exception", prog_fd); Ctrl-C of tracing daemon or cmdline tool that uses this feature will automatically detach bpf program, unload it and unregister tracepoint probe. On the kernel side the __bpf_raw_tp_map section of pointers to tracepoint definition and to __bpf_trace_*() probe function is used to find a tracepoint with "xdp_exception" name and corresponding __bpf_trace_xdp_exception() probe function which are passed to tracepoint_probe_register() to connect probe with tracepoint. Addition of bpf_raw_tracepoint doesn't interfere with ftrace and perf tracepoint mechanisms. perf_event_open() can be used in parallel on the same tracepoint. Multiple bpf_raw_tracepoint_open("xdp_exception", prog_fd) are permitted. Each with its own bpf program. The kernel will execute all tracepoint probes and all attached bpf programs. In the future bpf_raw_tracepoints can be extended with query/introspection logic. __bpf_raw_tp_map section logic was contributed by Steven Rostedt Signed-off-by: Alexei Starovoitov Signed-off-by: Steven Rostedt (VMware) Acked-by: Steven Rostedt (VMware) Signed-off-by: Daniel Borkmann --- include/asm-generic/vmlinux.lds.h | 10 +++ include/linux/bpf_types.h | 1 + include/linux/trace_events.h | 42 +++++++++ include/linux/tracepoint-defs.h | 6 ++ include/trace/bpf_probe.h | 92 +++++++++++++++++++ include/trace/define_trace.h | 1 + include/uapi/linux/bpf.h | 11 +++ kernel/bpf/syscall.c | 78 ++++++++++++++++ kernel/trace/bpf_trace.c | 183 ++++++++++++++++++++++++++++++++++++++ 9 files changed, 424 insertions(+) create mode 100644 include/trace/bpf_probe.h (limited to 'kernel/bpf/syscall.c') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 1ab0e520d6fc..8add3493a202 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -178,6 +178,15 @@ #define TRACE_SYSCALLS() #endif +#ifdef CONFIG_BPF_EVENTS +#define BPF_RAW_TP() STRUCT_ALIGN(); \ + VMLINUX_SYMBOL(__start__bpf_raw_tp) = .; \ + KEEP(*(__bpf_raw_tp_map)) \ + VMLINUX_SYMBOL(__stop__bpf_raw_tp) = .; +#else +#define BPF_RAW_TP() +#endif + #ifdef CONFIG_SERIAL_EARLYCON #define EARLYCON_TABLE() STRUCT_ALIGN(); \ VMLINUX_SYMBOL(__earlycon_table) = .; \ @@ -249,6 +258,7 @@ LIKELY_PROFILE() \ BRANCH_PROFILE() \ TRACE_PRINTKS() \ + BPF_RAW_TP() \ TRACEPOINT_STR() /* diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 5e2e8a49fb21..6d7243bfb0ff 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -19,6 +19,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_SK_MSG, sk_msg) BPF_PROG_TYPE(BPF_PROG_TYPE_KPROBE, kprobe) BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint) BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event) +BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint) #endif #ifdef CONFIG_CGROUP_BPF BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 8a1442c4e513..b0357cd198b0 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -468,6 +468,9 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx); int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog); void perf_event_detach_bpf_prog(struct perf_event *event); int perf_event_query_prog_array(struct perf_event *event, void __user *info); +int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog); +int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog); +struct bpf_raw_event_map *bpf_find_raw_tracepoint(const char *name); #else static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) { @@ -487,6 +490,18 @@ perf_event_query_prog_array(struct perf_event *event, void __user *info) { return -EOPNOTSUPP; } +static inline int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *p) +{ + return -EOPNOTSUPP; +} +static inline int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *p) +{ + return -EOPNOTSUPP; +} +static inline struct bpf_raw_event_map *bpf_find_raw_tracepoint(const char *name) +{ + return NULL; +} #endif enum { @@ -546,6 +561,33 @@ extern void ftrace_profile_free_filter(struct perf_event *event); void perf_trace_buf_update(void *record, u16 type); void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp); +void bpf_trace_run1(struct bpf_prog *prog, u64 arg1); +void bpf_trace_run2(struct bpf_prog *prog, u64 arg1, u64 arg2); +void bpf_trace_run3(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3); +void bpf_trace_run4(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4); +void bpf_trace_run5(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5); +void bpf_trace_run6(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6); +void bpf_trace_run7(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7); +void bpf_trace_run8(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7, + u64 arg8); +void bpf_trace_run9(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7, + u64 arg8, u64 arg9); +void bpf_trace_run10(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7, + u64 arg8, u64 arg9, u64 arg10); +void bpf_trace_run11(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7, + u64 arg8, u64 arg9, u64 arg10, u64 arg11); +void bpf_trace_run12(struct bpf_prog *prog, u64 arg1, u64 arg2, + u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7, + u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12); void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, struct trace_event_call *call, u64 count, struct pt_regs *regs, struct hlist_head *head, diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h index 64ed7064f1fa..22c5a46e9693 100644 --- a/include/linux/tracepoint-defs.h +++ b/include/linux/tracepoint-defs.h @@ -35,4 +35,10 @@ struct tracepoint { struct tracepoint_func __rcu *funcs; }; +struct bpf_raw_event_map { + struct tracepoint *tp; + void *bpf_func; + u32 num_args; +} __aligned(32); + #endif diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h new file mode 100644 index 000000000000..505dae0bed80 --- /dev/null +++ b/include/trace/bpf_probe.h @@ -0,0 +1,92 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#undef TRACE_SYSTEM_VAR + +#ifdef CONFIG_BPF_EVENTS + +#undef __entry +#define __entry entry + +#undef __get_dynamic_array +#define __get_dynamic_array(field) \ + ((void *)__entry + (__entry->__data_loc_##field & 0xffff)) + +#undef __get_dynamic_array_len +#define __get_dynamic_array_len(field) \ + ((__entry->__data_loc_##field >> 16) & 0xffff) + +#undef __get_str +#define __get_str(field) ((char *)__get_dynamic_array(field)) + +#undef __get_bitmask +#define __get_bitmask(field) (char *)__get_dynamic_array(field) + +#undef __perf_count +#define __perf_count(c) (c) + +#undef __perf_task +#define __perf_task(t) (t) + +/* cast any integer, pointer, or small struct to u64 */ +#define UINTTYPE(size) \ + __typeof__(__builtin_choose_expr(size == 1, (u8)1, \ + __builtin_choose_expr(size == 2, (u16)2, \ + __builtin_choose_expr(size == 4, (u32)3, \ + __builtin_choose_expr(size == 8, (u64)4, \ + (void)5))))) +#define __CAST_TO_U64(x) ({ \ + typeof(x) __src = (x); \ + UINTTYPE(sizeof(x)) __dst; \ + memcpy(&__dst, &__src, sizeof(__dst)); \ + (u64)__dst; }) + +#define __CAST1(a,...) __CAST_TO_U64(a) +#define __CAST2(a,...) __CAST_TO_U64(a), __CAST1(__VA_ARGS__) +#define __CAST3(a,...) __CAST_TO_U64(a), __CAST2(__VA_ARGS__) +#define __CAST4(a,...) __CAST_TO_U64(a), __CAST3(__VA_ARGS__) +#define __CAST5(a,...) __CAST_TO_U64(a), __CAST4(__VA_ARGS__) +#define __CAST6(a,...) __CAST_TO_U64(a), __CAST5(__VA_ARGS__) +#define __CAST7(a,...) __CAST_TO_U64(a), __CAST6(__VA_ARGS__) +#define __CAST8(a,...) __CAST_TO_U64(a), __CAST7(__VA_ARGS__) +#define __CAST9(a,...) __CAST_TO_U64(a), __CAST8(__VA_ARGS__) +#define __CAST10(a,...) __CAST_TO_U64(a), __CAST9(__VA_ARGS__) +#define __CAST11(a,...) __CAST_TO_U64(a), __CAST10(__VA_ARGS__) +#define __CAST12(a,...) __CAST_TO_U64(a), __CAST11(__VA_ARGS__) +/* tracepoints with more than 12 arguments will hit build error */ +#define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__) + +#undef DECLARE_EVENT_CLASS +#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ +static notrace void \ +__bpf_trace_##call(void *__data, proto) \ +{ \ + struct bpf_prog *prog = __data; \ + CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(prog, CAST_TO_U64(args)); \ +} + +/* + * This part is compiled out, it is only here as a build time check + * to make sure that if the tracepoint handling changes, the + * bpf probe will fail to compile unless it too is updated. + */ +#undef DEFINE_EVENT +#define DEFINE_EVENT(template, call, proto, args) \ +static inline void bpf_test_probe_##call(void) \ +{ \ + check_trace_callback_type_##call(__bpf_trace_##template); \ +} \ +static struct bpf_raw_event_map __used \ + __attribute__((section("__bpf_raw_tp_map"))) \ +__bpf_trace_tp_map_##call = { \ + .tp = &__tracepoint_##call, \ + .bpf_func = (void *)__bpf_trace_##template, \ + .num_args = COUNT_ARGS(args), \ +}; + + +#undef DEFINE_EVENT_PRINT +#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ + DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args)) + +#include TRACE_INCLUDE(TRACE_INCLUDE_FILE) +#endif /* CONFIG_BPF_EVENTS */ diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h index d9e3d4aa3f6e..cb30c5532144 100644 --- a/include/trace/define_trace.h +++ b/include/trace/define_trace.h @@ -95,6 +95,7 @@ #ifdef TRACEPOINTS_ENABLED #include #include +#include #endif #undef TRACE_EVENT diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 18b7c510c511..1878201c2d77 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -94,6 +94,7 @@ enum bpf_cmd { BPF_MAP_GET_FD_BY_ID, BPF_OBJ_GET_INFO_BY_FD, BPF_PROG_QUERY, + BPF_RAW_TRACEPOINT_OPEN, }; enum bpf_map_type { @@ -134,6 +135,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_SK_SKB, BPF_PROG_TYPE_CGROUP_DEVICE, BPF_PROG_TYPE_SK_MSG, + BPF_PROG_TYPE_RAW_TRACEPOINT, }; enum bpf_attach_type { @@ -344,6 +346,11 @@ union bpf_attr { __aligned_u64 prog_ids; __u32 prog_cnt; } query; + + struct { + __u64 name; + __u32 prog_fd; + } raw_tracepoint; } __attribute__((aligned(8))); /* BPF helper function descriptions: @@ -1152,4 +1159,8 @@ struct bpf_cgroup_dev_ctx { __u32 minor; }; +struct bpf_raw_tracepoint_args { + __u64 args[0]; +}; + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 77d45bd9f507..95ca2523fa6e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1315,6 +1315,81 @@ static int bpf_obj_get(const union bpf_attr *attr) attr->file_flags); } +struct bpf_raw_tracepoint { + struct bpf_raw_event_map *btp; + struct bpf_prog *prog; +}; + +static int bpf_raw_tracepoint_release(struct inode *inode, struct file *filp) +{ + struct bpf_raw_tracepoint *raw_tp = filp->private_data; + + if (raw_tp->prog) { + bpf_probe_unregister(raw_tp->btp, raw_tp->prog); + bpf_prog_put(raw_tp->prog); + } + kfree(raw_tp); + return 0; +} + +static const struct file_operations bpf_raw_tp_fops = { + .release = bpf_raw_tracepoint_release, + .read = bpf_dummy_read, + .write = bpf_dummy_write, +}; + +#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd + +static int bpf_raw_tracepoint_open(const union bpf_attr *attr) +{ + struct bpf_raw_tracepoint *raw_tp; + struct bpf_raw_event_map *btp; + struct bpf_prog *prog; + char tp_name[128]; + int tp_fd, err; + + if (strncpy_from_user(tp_name, u64_to_user_ptr(attr->raw_tracepoint.name), + sizeof(tp_name) - 1) < 0) + return -EFAULT; + tp_name[sizeof(tp_name) - 1] = 0; + + btp = bpf_find_raw_tracepoint(tp_name); + if (!btp) + return -ENOENT; + + raw_tp = kzalloc(sizeof(*raw_tp), GFP_USER); + if (!raw_tp) + return -ENOMEM; + raw_tp->btp = btp; + + prog = bpf_prog_get_type(attr->raw_tracepoint.prog_fd, + BPF_PROG_TYPE_RAW_TRACEPOINT); + if (IS_ERR(prog)) { + err = PTR_ERR(prog); + goto out_free_tp; + } + + err = bpf_probe_register(raw_tp->btp, prog); + if (err) + goto out_put_prog; + + raw_tp->prog = prog; + tp_fd = anon_inode_getfd("bpf-raw-tracepoint", &bpf_raw_tp_fops, raw_tp, + O_CLOEXEC); + if (tp_fd < 0) { + bpf_probe_unregister(raw_tp->btp, prog); + err = tp_fd; + goto out_put_prog; + } + return tp_fd; + +out_put_prog: + bpf_prog_put(prog); +out_free_tp: + kfree(raw_tp); + return err; +} + #ifdef CONFIG_CGROUP_BPF #define BPF_PROG_ATTACH_LAST_FIELD attach_flags @@ -1925,6 +2000,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_OBJ_GET_INFO_BY_FD: err = bpf_obj_get_info_by_fd(&attr, uattr); break; + case BPF_RAW_TRACEPOINT_OPEN: + err = bpf_raw_tracepoint_open(&attr); + break; default: err = -EINVAL; break; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 7f9691c86b6e..463e72d18c4c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -735,6 +735,86 @@ static const struct bpf_func_proto *pe_prog_func_proto(enum bpf_func_id func_id) } } +/* + * bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp + * to avoid potential recursive reuse issue when/if tracepoints are added + * inside bpf_*_event_output and/or bpf_get_stack_id + */ +static DEFINE_PER_CPU(struct pt_regs, bpf_raw_tp_regs); +BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args, + struct bpf_map *, map, u64, flags, void *, data, u64, size) +{ + struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + + perf_fetch_caller_regs(regs); + return ____bpf_perf_event_output(regs, map, flags, data, size); +} + +static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { + .func = bpf_perf_event_output_raw_tp, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_MEM, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + +BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, + struct bpf_map *, map, u64, flags) +{ + struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs); + + perf_fetch_caller_regs(regs); + /* similar to bpf_perf_event_output_tp, but pt_regs fetched differently */ + return bpf_get_stackid((unsigned long) regs, (unsigned long) map, + flags, 0, 0); +} + +static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { + .func = bpf_get_stackid_raw_tp, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, +}; + +static const struct bpf_func_proto *raw_tp_prog_func_proto(enum bpf_func_id func_id) +{ + switch (func_id) { + case BPF_FUNC_perf_event_output: + return &bpf_perf_event_output_proto_raw_tp; + case BPF_FUNC_get_stackid: + return &bpf_get_stackid_proto_raw_tp; + default: + return tracing_func_proto(func_id); + } +} + +static bool raw_tp_prog_is_valid_access(int off, int size, + enum bpf_access_type type, + struct bpf_insn_access_aux *info) +{ + /* largest tracepoint in the kernel has 12 args */ + if (off < 0 || off >= sizeof(__u64) * 12) + return false; + if (type != BPF_READ) + return false; + if (off % size != 0) + return false; + return true; +} + +const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { + .get_func_proto = raw_tp_prog_func_proto, + .is_valid_access = raw_tp_prog_is_valid_access, +}; + +const struct bpf_prog_ops raw_tracepoint_prog_ops = { +}; + static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, struct bpf_insn_access_aux *info) { @@ -908,3 +988,106 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) return ret; } + +extern struct bpf_raw_event_map __start__bpf_raw_tp[]; +extern struct bpf_raw_event_map __stop__bpf_raw_tp[]; + +struct bpf_raw_event_map *bpf_find_raw_tracepoint(const char *name) +{ + struct bpf_raw_event_map *btp = __start__bpf_raw_tp; + + for (; btp < __stop__bpf_raw_tp; btp++) { + if (!strcmp(btp->tp->name, name)) + return btp; + } + return NULL; +} + +static __always_inline +void __bpf_trace_run(struct bpf_prog *prog, u64 *args) +{ + rcu_read_lock(); + preempt_disable(); + (void) BPF_PROG_RUN(prog, args); + preempt_enable(); + rcu_read_unlock(); +} + +#define UNPACK(...) __VA_ARGS__ +#define REPEAT_1(FN, DL, X, ...) FN(X) +#define REPEAT_2(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__) +#define REPEAT_3(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__) +#define REPEAT_4(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__) +#define REPEAT_5(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__) +#define REPEAT_6(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__) +#define REPEAT_7(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__) +#define REPEAT_8(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__) +#define REPEAT_9(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__) +#define REPEAT_10(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_9(FN, DL, __VA_ARGS__) +#define REPEAT_11(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_10(FN, DL, __VA_ARGS__) +#define REPEAT_12(FN, DL, X, ...) FN(X) UNPACK DL REPEAT_11(FN, DL, __VA_ARGS__) +#define REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__) + +#define SARG(X) u64 arg##X +#define COPY(X) args[X] = arg##X + +#define __DL_COM (,) +#define __DL_SEM (;) + +#define __SEQ_0_11 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 + +#define BPF_TRACE_DEFN_x(x) \ + void bpf_trace_run##x(struct bpf_prog *prog, \ + REPEAT(x, SARG, __DL_COM, __SEQ_0_11)) \ + { \ + u64 args[x]; \ + REPEAT(x, COPY, __DL_SEM, __SEQ_0_11); \ + __bpf_trace_run(prog, args); \ + } \ + EXPORT_SYMBOL_GPL(bpf_trace_run##x) +BPF_TRACE_DEFN_x(1); +BPF_TRACE_DEFN_x(2); +BPF_TRACE_DEFN_x(3); +BPF_TRACE_DEFN_x(4); +BPF_TRACE_DEFN_x(5); +BPF_TRACE_DEFN_x(6); +BPF_TRACE_DEFN_x(7); +BPF_TRACE_DEFN_x(8); +BPF_TRACE_DEFN_x(9); +BPF_TRACE_DEFN_x(10); +BPF_TRACE_DEFN_x(11); +BPF_TRACE_DEFN_x(12); + +static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +{ + struct tracepoint *tp = btp->tp; + + /* + * check that program doesn't access arguments beyond what's + * available in this tracepoint + */ + if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64)) + return -EINVAL; + + return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog); +} + +int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +{ + int err; + + mutex_lock(&bpf_event_mutex); + err = __bpf_probe_register(btp, prog); + mutex_unlock(&bpf_event_mutex); + return err; +} + +int bpf_probe_unregister(struct bpf_raw_event_map *btp, struct bpf_prog *prog) +{ + int err; + + mutex_lock(&bpf_event_mutex); + err = tracepoint_probe_unregister(btp->tp, (void *)btp->bpf_func, prog); + mutex_unlock(&bpf_event_mutex); + return err; +} -- cgit v1.2.3 From 5e43f899b03a3492ce5fc44e8900becb04dae9c0 Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Fri, 30 Mar 2018 15:08:00 -0700 Subject: bpf: Check attach type at prog load time == The problem == There are use-cases when a program of some type can be attached to multiple attach points and those attach points must have different permissions to access context or to call helpers. E.g. context structure may have fields for both IPv4 and IPv6 but it doesn't make sense to read from / write to IPv6 field when attach point is somewhere in IPv4 stack. Same applies to BPF-helpers: it may make sense to call some helper from some attach point, but not from other for same prog type. == The solution == Introduce `expected_attach_type` field in in `struct bpf_attr` for `BPF_PROG_LOAD` command. If scenario described in "The problem" section is the case for some prog type, the field will be checked twice: 1) At load time prog type is checked to see if attach type for it must be known to validate program permissions correctly. Prog will be rejected with EINVAL if it's the case and `expected_attach_type` is not specified or has invalid value. 2) At attach time `attach_type` is compared with `expected_attach_type`, if prog type requires to have one, and, if they differ, attach will be rejected with EINVAL. The `expected_attach_type` is now available as part of `struct bpf_prog` in both `bpf_verifier_ops->is_valid_access()` and `bpf_verifier_ops->get_func_proto()` () and can be used to check context accesses and calls to helpers correspondingly. Initially the idea was discussed by Alexei Starovoitov and Daniel Borkmann here: https://marc.info/?l=linux-netdev&m=152107378717201&w=2 Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 5 ++++- include/linux/filter.h | 1 + include/uapi/linux/bpf.h | 5 +++++ kernel/bpf/cgroup.c | 3 ++- kernel/bpf/syscall.c | 31 ++++++++++++++++++++++++++++++- kernel/bpf/verifier.c | 6 +++--- kernel/trace/bpf_trace.c | 27 ++++++++++++++++++--------- net/core/filter.c | 39 +++++++++++++++++++++++++-------------- 8 files changed, 88 insertions(+), 29 deletions(-) (limited to 'kernel/bpf/syscall.c') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 819229c80eca..95a7abd0ee92 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -208,12 +208,15 @@ struct bpf_prog_ops { struct bpf_verifier_ops { /* return eBPF function prototype for verification */ - const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); + const struct bpf_func_proto * + (*get_func_proto)(enum bpf_func_id func_id, + const struct bpf_prog *prog); /* return true if 'size' wide access at offset 'off' within bpf_context * with 'type' (read or write) is allowed */ bool (*is_valid_access)(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info); int (*gen_prologue)(struct bpf_insn *insn, bool direct_write, const struct bpf_prog *prog); diff --git a/include/linux/filter.h b/include/linux/filter.h index 897ff3d95968..13c044e4832d 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -469,6 +469,7 @@ struct bpf_prog { is_func:1, /* program is a bpf function */ kprobe_override:1; /* Do we override a kprobe? */ enum bpf_prog_type type; /* Type of BPF program */ + enum bpf_attach_type expected_attach_type; /* For some prog types */ u32 len; /* Number of filter blocks */ u32 jited_len; /* Size of jited insns in bytes */ u8 tag[BPF_TAG_SIZE]; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1878201c2d77..102718624d1e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -296,6 +296,11 @@ union bpf_attr { __u32 prog_flags; char prog_name[BPF_OBJ_NAME_LEN]; __u32 prog_ifindex; /* ifindex of netdev to prep for */ + /* For some prog types expected attach type must be known at + * load time to verify attach type specific parts of prog + * (context accesses, allowed helpers, etc). + */ + __u32 expected_attach_type; }; struct { /* anonymous struct used by BPF_OBJ_* commands */ diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index c1c0b60d3f2f..8730b24ed540 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -545,7 +545,7 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, EXPORT_SYMBOL(__cgroup_bpf_check_dev_permission); static const struct bpf_func_proto * -cgroup_dev_func_proto(enum bpf_func_id func_id) +cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_map_lookup_elem: @@ -566,6 +566,7 @@ cgroup_dev_func_proto(enum bpf_func_id func_id) static bool cgroup_dev_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { const int size_default = sizeof(__u32); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 95ca2523fa6e..9d3b572d4dec 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1171,8 +1171,27 @@ struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type, } EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev); +static int +bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type, + enum bpf_attach_type expected_attach_type) +{ + /* There are currently no prog types that require specifying + * attach_type at load time. + */ + return 0; +} + +static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, + enum bpf_attach_type attach_type) +{ + /* There are currently no prog types that require specifying + * attach_type at load time. + */ + return 0; +} + /* last field in 'union bpf_attr' used by this command */ -#define BPF_PROG_LOAD_LAST_FIELD prog_ifindex +#define BPF_PROG_LOAD_LAST_FIELD expected_attach_type static int bpf_prog_load(union bpf_attr *attr) { @@ -1209,11 +1228,16 @@ static int bpf_prog_load(union bpf_attr *attr) !capable(CAP_SYS_ADMIN)) return -EPERM; + if (bpf_prog_load_check_attach_type(type, attr->expected_attach_type)) + return -EINVAL; + /* plain bpf_prog allocation */ prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); if (!prog) return -ENOMEM; + prog->expected_attach_type = attr->expected_attach_type; + prog->aux->offload_requested = !!attr->prog_ifindex; err = security_bpf_prog_alloc(prog->aux); @@ -1474,6 +1498,11 @@ static int bpf_prog_attach(const union bpf_attr *attr) if (IS_ERR(prog)) return PTR_ERR(prog); + if (bpf_prog_attach_check_attach_type(prog, attr->attach_type)) { + bpf_prog_put(prog); + return -EINVAL; + } + cgrp = cgroup_get_from_fd(attr->target_fd); if (IS_ERR(cgrp)) { bpf_prog_put(prog); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8acd2207e412..10024323031d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1323,7 +1323,7 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, }; if (env->ops->is_valid_access && - env->ops->is_valid_access(off, size, t, &info)) { + env->ops->is_valid_access(off, size, t, env->prog, &info)) { /* A non zero info.ctx_field_size indicates that this field is a * candidate for later verifier transformation to load the whole * field and then apply a mask when accessed with a narrower @@ -2349,7 +2349,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn } if (env->ops->get_func_proto) - fn = env->ops->get_func_proto(func_id); + fn = env->ops->get_func_proto(func_id, env->prog); if (!fn) { verbose(env, "unknown func %s#%d\n", func_id_name(func_id), func_id); @@ -5572,7 +5572,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) insn = new_prog->insnsi + i + delta; } patch_call_imm: - fn = env->ops->get_func_proto(insn->imm); + fn = env->ops->get_func_proto(insn->imm, env->prog); /* all functions that have prototype and verifier allowed * programs to call them, must be real in-kernel functions */ diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 463e72d18c4c..d88e96d4e12c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -524,7 +524,8 @@ static const struct bpf_func_proto bpf_probe_read_str_proto = { .arg3_type = ARG_ANYTHING, }; -static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_map_lookup_elem: @@ -568,7 +569,8 @@ static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) } } -static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_perf_event_output: @@ -582,12 +584,13 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func return &bpf_override_return_proto; #endif default: - return tracing_func_proto(func_id); + return tracing_func_proto(func_id, prog); } } /* bpf+kprobe programs can access fields of 'struct pt_regs' */ static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { if (off < 0 || off >= sizeof(struct pt_regs)) @@ -661,7 +664,8 @@ static const struct bpf_func_proto bpf_get_stackid_proto_tp = { .arg3_type = ARG_ANYTHING, }; -static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_perf_event_output: @@ -669,11 +673,12 @@ static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id) case BPF_FUNC_get_stackid: return &bpf_get_stackid_proto_tp; default: - return tracing_func_proto(func_id); + return tracing_func_proto(func_id, prog); } } static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE) @@ -721,7 +726,8 @@ static const struct bpf_func_proto bpf_perf_prog_read_value_proto = { .arg3_type = ARG_CONST_SIZE, }; -static const struct bpf_func_proto *pe_prog_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_perf_event_output: @@ -731,7 +737,7 @@ static const struct bpf_func_proto *pe_prog_func_proto(enum bpf_func_id func_id) case BPF_FUNC_perf_prog_read_value: return &bpf_perf_prog_read_value_proto; default: - return tracing_func_proto(func_id); + return tracing_func_proto(func_id, prog); } } @@ -781,7 +787,8 @@ static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = { .arg3_type = ARG_ANYTHING, }; -static const struct bpf_func_proto *raw_tp_prog_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_perf_event_output: @@ -789,12 +796,13 @@ static const struct bpf_func_proto *raw_tp_prog_func_proto(enum bpf_func_id func case BPF_FUNC_get_stackid: return &bpf_get_stackid_proto_raw_tp; default: - return tracing_func_proto(func_id); + return tracing_func_proto(func_id, prog); } } static bool raw_tp_prog_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { /* largest tracepoint in the kernel has 12 args */ @@ -816,6 +824,7 @@ const struct bpf_prog_ops raw_tracepoint_prog_ops = { }; static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { const int size_u64 = sizeof(u64); diff --git a/net/core/filter.c b/net/core/filter.c index e989bf313195..7790fd128614 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3685,7 +3685,7 @@ bpf_base_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * -sock_filter_func_proto(enum bpf_func_id func_id) +sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { /* inet and inet6 sockets are created in a process @@ -3699,7 +3699,7 @@ sock_filter_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * -sk_filter_func_proto(enum bpf_func_id func_id) +sk_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_skb_load_bytes: @@ -3714,7 +3714,7 @@ sk_filter_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * -tc_cls_act_func_proto(enum bpf_func_id func_id) +tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_skb_store_bytes: @@ -3781,7 +3781,7 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * -xdp_func_proto(enum bpf_func_id func_id) +xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_perf_event_output: @@ -3804,7 +3804,7 @@ xdp_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * -lwt_inout_func_proto(enum bpf_func_id func_id) +lwt_inout_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_skb_load_bytes: @@ -3831,7 +3831,7 @@ lwt_inout_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * - sock_ops_func_proto(enum bpf_func_id func_id) +sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_setsockopt: @@ -3847,7 +3847,8 @@ static const struct bpf_func_proto * } } -static const struct bpf_func_proto *sk_msg_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_msg_redirect_map: @@ -3863,7 +3864,8 @@ static const struct bpf_func_proto *sk_msg_func_proto(enum bpf_func_id func_id) } } -static const struct bpf_func_proto *sk_skb_func_proto(enum bpf_func_id func_id) +static const struct bpf_func_proto * +sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_skb_store_bytes: @@ -3888,7 +3890,7 @@ static const struct bpf_func_proto *sk_skb_func_proto(enum bpf_func_id func_id) } static const struct bpf_func_proto * -lwt_xmit_func_proto(enum bpf_func_id func_id) +lwt_xmit_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_skb_get_tunnel_key: @@ -3918,11 +3920,12 @@ lwt_xmit_func_proto(enum bpf_func_id func_id) case BPF_FUNC_set_hash_invalid: return &bpf_set_hash_invalid_proto; default: - return lwt_inout_func_proto(func_id); + return lwt_inout_func_proto(func_id, prog); } } static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { const int size_default = sizeof(__u32); @@ -3966,6 +3969,7 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type static bool sk_filter_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { switch (off) { @@ -3986,11 +3990,12 @@ static bool sk_filter_is_valid_access(int off, int size, } } - return bpf_skb_is_valid_access(off, size, type, info); + return bpf_skb_is_valid_access(off, size, type, prog, info); } static bool lwt_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { switch (off) { @@ -4020,11 +4025,12 @@ static bool lwt_is_valid_access(int off, int size, break; } - return bpf_skb_is_valid_access(off, size, type, info); + return bpf_skb_is_valid_access(off, size, type, prog, info); } static bool sock_filter_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { if (type == BPF_WRITE) { @@ -4096,6 +4102,7 @@ static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write, static bool tc_cls_act_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { if (type == BPF_WRITE) { @@ -4125,7 +4132,7 @@ static bool tc_cls_act_is_valid_access(int off, int size, return false; } - return bpf_skb_is_valid_access(off, size, type, info); + return bpf_skb_is_valid_access(off, size, type, prog, info); } static bool __is_valid_xdp_access(int off, int size) @@ -4142,6 +4149,7 @@ static bool __is_valid_xdp_access(int off, int size) static bool xdp_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { if (type == BPF_WRITE) @@ -4174,6 +4182,7 @@ EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action); static bool sock_ops_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { const int size_default = sizeof(__u32); @@ -4220,6 +4229,7 @@ static int sk_skb_prologue(struct bpf_insn *insn_buf, bool direct_write, static bool sk_skb_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { switch (off) { @@ -4249,11 +4259,12 @@ static bool sk_skb_is_valid_access(int off, int size, break; } - return bpf_skb_is_valid_access(off, size, type, info); + return bpf_skb_is_valid_access(off, size, type, prog, info); } static bool sk_msg_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { if (type == BPF_WRITE) -- cgit v1.2.3 From 4fbac77d2d092b475dda9eea66da674369665427 Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Fri, 30 Mar 2018 15:08:02 -0700 Subject: bpf: Hooks for sys_bind == The problem == There is a use-case when all processes inside a cgroup should use one single IP address on a host that has multiple IP configured. Those processes should use the IP for both ingress and egress, for TCP and UDP traffic. So TCP/UDP servers should be bound to that IP to accept incoming connections on it, and TCP/UDP clients should make outgoing connections from that IP. It should not require changing application code since it's often not possible. Currently it's solved by intercepting glibc wrappers around syscalls such as `bind(2)` and `connect(2)`. It's done by a shared library that is preloaded for every process in a cgroup so that whenever TCP/UDP server calls `bind(2)`, the library replaces IP in sockaddr before passing arguments to syscall. When application calls `connect(2)` the library transparently binds the local end of connection to that IP (`bind(2)` with `IP_BIND_ADDRESS_NO_PORT` to avoid performance penalty). Shared library approach is fragile though, e.g.: * some applications clear env vars (incl. `LD_PRELOAD`); * `/etc/ld.so.preload` doesn't help since some applications are linked with option `-z nodefaultlib`; * other applications don't use glibc and there is nothing to intercept. == The solution == The patch provides much more reliable in-kernel solution for the 1st part of the problem: binding TCP/UDP servers on desired IP. It does not depend on application environment and implementation details (whether glibc is used or not). It adds new eBPF program type `BPF_PROG_TYPE_CGROUP_SOCK_ADDR` and attach types `BPF_CGROUP_INET4_BIND` and `BPF_CGROUP_INET6_BIND` (similar to already existing `BPF_CGROUP_INET_SOCK_CREATE`). The new program type is intended to be used with sockets (`struct sock`) in a cgroup and provided by user `struct sockaddr`. Pointers to both of them are parts of the context passed to programs of newly added types. The new attach types provides hooks in `bind(2)` system call for both IPv4 and IPv6 so that one can write a program to override IP addresses and ports user program tries to bind to and apply such a program for whole cgroup. == Implementation notes == [1] Separate attach types for `AF_INET` and `AF_INET6` are added intentionally to prevent reading/writing to offsets that don't make sense for corresponding socket family. E.g. if user passes `sockaddr_in` it doesn't make sense to read from / write to `user_ip6[]` context fields. [2] The write access to `struct bpf_sock_addr_kern` is implemented using special field as an additional "register". There are just two registers in `sock_addr_convert_ctx_access`: `src` with value to write and `dst` with pointer to context that can't be changed not to break later instructions. But the fields, allowed to write to, are not available directly and to access them address of corresponding pointer has to be loaded first. To get additional register the 1st not used by `src` and `dst` one is taken, its content is saved to `bpf_sock_addr_kern.tmp_reg`, then the register is used to load address of pointer field, and finally the register's content is restored from the temporary field after writing `src` value. Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- include/linux/bpf-cgroup.h | 21 ++++ include/linux/bpf_types.h | 1 + include/linux/filter.h | 10 ++ include/uapi/linux/bpf.h | 23 +++++ kernel/bpf/cgroup.c | 36 +++++++ kernel/bpf/syscall.c | 36 +++++-- kernel/bpf/verifier.c | 1 + net/core/filter.c | 232 +++++++++++++++++++++++++++++++++++++++++++++ net/ipv4/af_inet.c | 7 ++ net/ipv6/af_inet6.c | 7 ++ 10 files changed, 366 insertions(+), 8 deletions(-) (limited to 'kernel/bpf/syscall.c') diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 8a4566691c8f..67dc4a6471ad 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -6,6 +6,7 @@ #include struct sock; +struct sockaddr; struct cgroup; struct sk_buff; struct bpf_sock_ops_kern; @@ -63,6 +64,10 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk, int __cgroup_bpf_run_filter_sk(struct sock *sk, enum bpf_attach_type type); +int __cgroup_bpf_run_filter_sock_addr(struct sock *sk, + struct sockaddr *uaddr, + enum bpf_attach_type type); + int __cgroup_bpf_run_filter_sock_ops(struct sock *sk, struct bpf_sock_ops_kern *sock_ops, enum bpf_attach_type type); @@ -103,6 +108,20 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, __ret; \ }) +#define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, type) \ +({ \ + int __ret = 0; \ + if (cgroup_bpf_enabled) \ + __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type); \ + __ret; \ +}) + +#define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) \ + BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET4_BIND) + +#define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) \ + BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET6_BIND) + #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) \ ({ \ int __ret = 0; \ @@ -135,6 +154,8 @@ static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; }) #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type,major,minor,access) ({ 0; }) diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 6d7243bfb0ff..2b28fcf6f6ae 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -8,6 +8,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_SCHED_ACT, tc_cls_act) BPF_PROG_TYPE(BPF_PROG_TYPE_XDP, xdp) BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SKB, cg_skb) BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCK, cg_sock) +BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, cg_sock_addr) BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_IN, lwt_inout) BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_OUT, lwt_inout) BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_XMIT, lwt_xmit) diff --git a/include/linux/filter.h b/include/linux/filter.h index 13c044e4832d..fc4e8f91b03d 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1021,6 +1021,16 @@ static inline int bpf_tell_extensions(void) return SKF_AD_MAX; } +struct bpf_sock_addr_kern { + struct sock *sk; + struct sockaddr *uaddr; + /* Temporary "register" to make indirect stores to nested structures + * defined above. We need three registers to make such a store, but + * only two (src and dst) are available at convert_ctx_access time + */ + u64 tmp_reg; +}; + struct bpf_sock_ops_kern { struct sock *sk; u32 op; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 102718624d1e..ce3e69e3c793 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -136,6 +136,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_CGROUP_DEVICE, BPF_PROG_TYPE_SK_MSG, BPF_PROG_TYPE_RAW_TRACEPOINT, + BPF_PROG_TYPE_CGROUP_SOCK_ADDR, }; enum bpf_attach_type { @@ -147,6 +148,8 @@ enum bpf_attach_type { BPF_SK_SKB_STREAM_VERDICT, BPF_CGROUP_DEVICE, BPF_SK_MSG_VERDICT, + BPF_CGROUP_INET4_BIND, + BPF_CGROUP_INET6_BIND, __MAX_BPF_ATTACH_TYPE }; @@ -1010,6 +1013,26 @@ struct bpf_map_info { __u64 netns_ino; } __attribute__((aligned(8))); +/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed + * by user and intended to be used by socket (e.g. to bind to, depends on + * attach attach type). + */ +struct bpf_sock_addr { + __u32 user_family; /* Allows 4-byte read, but no write. */ + __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write. + * Stored in network byte order. + */ + __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write. + * Stored in network byte order. + */ + __u32 user_port; /* Allows 4-byte read and write. + * Stored in network byte order + */ + __u32 family; /* Allows 4-byte read, but no write */ + __u32 type; /* Allows 4-byte read, but no write */ + __u32 protocol; /* Allows 4-byte read, but no write */ +}; + /* User bpf_sock_ops struct to access socket values and specify request ops * and their replies. * Some of this fields are in network (bigendian) byte order and may need diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 8730b24ed540..43171a0bb02b 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -494,6 +494,42 @@ int __cgroup_bpf_run_filter_sk(struct sock *sk, } EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk); +/** + * __cgroup_bpf_run_filter_sock_addr() - Run a program on a sock and + * provided by user sockaddr + * @sk: sock struct that will use sockaddr + * @uaddr: sockaddr struct provided by user + * @type: The type of program to be exectuted + * + * socket is expected to be of type INET or INET6. + * + * This function will return %-EPERM if an attached program is found and + * returned value != 1 during execution. In all other cases, 0 is returned. + */ +int __cgroup_bpf_run_filter_sock_addr(struct sock *sk, + struct sockaddr *uaddr, + enum bpf_attach_type type) +{ + struct bpf_sock_addr_kern ctx = { + .sk = sk, + .uaddr = uaddr, + }; + struct cgroup *cgrp; + int ret; + + /* Check socket family since not all sockets represent network + * endpoint (e.g. AF_UNIX). + */ + if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6) + return 0; + + cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data); + ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN); + + return ret == 1 ? 0 : -EPERM; +} +EXPORT_SYMBOL(__cgroup_bpf_run_filter_sock_addr); + /** * __cgroup_bpf_run_filter_sock_ops() - Run a program on a sock * @sk: socket to get cgroup from diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 9d3b572d4dec..2cad66a4cacb 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1175,19 +1175,29 @@ static int bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type, enum bpf_attach_type expected_attach_type) { - /* There are currently no prog types that require specifying - * attach_type at load time. - */ - return 0; + switch (prog_type) { + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: + switch (expected_attach_type) { + case BPF_CGROUP_INET4_BIND: + case BPF_CGROUP_INET6_BIND: + return 0; + default: + return -EINVAL; + } + default: + return 0; + } } static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, enum bpf_attach_type attach_type) { - /* There are currently no prog types that require specifying - * attach_type at load time. - */ - return 0; + switch (prog->type) { + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: + return attach_type == prog->expected_attach_type ? 0 : -EINVAL; + default: + return 0; + } } /* last field in 'union bpf_attr' used by this command */ @@ -1479,6 +1489,10 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_CGROUP_INET_SOCK_CREATE: ptype = BPF_PROG_TYPE_CGROUP_SOCK; break; + case BPF_CGROUP_INET4_BIND: + case BPF_CGROUP_INET6_BIND: + ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR; + break; case BPF_CGROUP_SOCK_OPS: ptype = BPF_PROG_TYPE_SOCK_OPS; break; @@ -1541,6 +1555,10 @@ static int bpf_prog_detach(const union bpf_attr *attr) case BPF_CGROUP_INET_SOCK_CREATE: ptype = BPF_PROG_TYPE_CGROUP_SOCK; break; + case BPF_CGROUP_INET4_BIND: + case BPF_CGROUP_INET6_BIND: + ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR; + break; case BPF_CGROUP_SOCK_OPS: ptype = BPF_PROG_TYPE_SOCK_OPS; break; @@ -1590,6 +1608,8 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_CGROUP_INET_INGRESS: case BPF_CGROUP_INET_EGRESS: case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET4_BIND: + case BPF_CGROUP_INET6_BIND: case BPF_CGROUP_SOCK_OPS: case BPF_CGROUP_DEVICE: break; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 10024323031d..5dd1dcb902bf 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3887,6 +3887,7 @@ static int check_return_code(struct bpf_verifier_env *env) switch (env->prog->type) { case BPF_PROG_TYPE_CGROUP_SKB: case BPF_PROG_TYPE_CGROUP_SOCK: + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: case BPF_PROG_TYPE_SOCK_OPS: case BPF_PROG_TYPE_CGROUP_DEVICE: break; diff --git a/net/core/filter.c b/net/core/filter.c index 7790fd128614..c08e5b121558 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3698,6 +3698,20 @@ sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) } } +static const struct bpf_func_proto * +sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + switch (func_id) { + /* inet and inet6 sockets are created in a process + * context so there is always a valid uid/gid + */ + case BPF_FUNC_get_current_uid_gid: + return &bpf_get_current_uid_gid_proto; + default: + return bpf_base_func_proto(func_id); + } +} + static const struct bpf_func_proto * sk_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -4180,6 +4194,69 @@ void bpf_warn_invalid_xdp_action(u32 act) } EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action); +static bool sock_addr_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + const int size_default = sizeof(__u32); + + if (off < 0 || off >= sizeof(struct bpf_sock_addr)) + return false; + if (off % size != 0) + return false; + + /* Disallow access to IPv6 fields from IPv4 contex and vise + * versa. + */ + switch (off) { + case bpf_ctx_range(struct bpf_sock_addr, user_ip4): + switch (prog->expected_attach_type) { + case BPF_CGROUP_INET4_BIND: + break; + default: + return false; + } + break; + case bpf_ctx_range_till(struct bpf_sock_addr, user_ip6[0], user_ip6[3]): + switch (prog->expected_attach_type) { + case BPF_CGROUP_INET6_BIND: + break; + default: + return false; + } + break; + } + + switch (off) { + case bpf_ctx_range(struct bpf_sock_addr, user_ip4): + case bpf_ctx_range_till(struct bpf_sock_addr, user_ip6[0], user_ip6[3]): + /* Only narrow read access allowed for now. */ + if (type == BPF_READ) { + bpf_ctx_record_field_size(info, size_default); + if (!bpf_ctx_narrow_access_ok(off, size, size_default)) + return false; + } else { + if (size != size_default) + return false; + } + break; + case bpf_ctx_range(struct bpf_sock_addr, user_port): + if (size != size_default) + return false; + break; + default: + if (type == BPF_READ) { + if (size != size_default) + return false; + } else { + return false; + } + } + + return true; +} + static bool sock_ops_is_valid_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, @@ -4724,6 +4801,152 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type, return insn - insn_buf; } +/* SOCK_ADDR_LOAD_NESTED_FIELD() loads Nested Field S.F.NF where S is type of + * context Structure, F is Field in context structure that contains a pointer + * to Nested Structure of type NS that has the field NF. + * + * SIZE encodes the load size (BPF_B, BPF_H, etc). It's up to caller to make + * sure that SIZE is not greater than actual size of S.F.NF. + * + * If offset OFF is provided, the load happens from that offset relative to + * offset of NF. + */ +#define SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF(S, NS, F, NF, SIZE, OFF) \ + do { \ + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), si->dst_reg, \ + si->src_reg, offsetof(S, F)); \ + *insn++ = BPF_LDX_MEM( \ + SIZE, si->dst_reg, si->dst_reg, \ + bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ + target_size) \ + + OFF); \ + } while (0) + +#define SOCK_ADDR_LOAD_NESTED_FIELD(S, NS, F, NF) \ + SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF(S, NS, F, NF, \ + BPF_FIELD_SIZEOF(NS, NF), 0) + +/* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to + * SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation. + * + * It doesn't support SIZE argument though since narrow stores are not + * supported for now. + * + * In addition it uses Temporary Field TF (member of struct S) as the 3rd + * "register" since two registers available in convert_ctx_access are not + * enough: we can't override neither SRC, since it contains value to store, nor + * DST since it contains pointer to context that may be used by later + * instructions. But we need a temporary place to save pointer to nested + * structure whose field we want to store to. + */ +#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \ + do { \ + int tmp_reg = BPF_REG_9; \ + if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ + --tmp_reg; \ + if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \ + --tmp_reg; \ + *insn++ = BPF_STX_MEM(BPF_DW, si->dst_reg, tmp_reg, \ + offsetof(S, TF)); \ + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \ + si->dst_reg, offsetof(S, F)); \ + *insn++ = BPF_STX_MEM( \ + BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \ + bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \ + target_size) \ + + OFF); \ + *insn++ = BPF_LDX_MEM(BPF_DW, tmp_reg, si->dst_reg, \ + offsetof(S, TF)); \ + } while (0) + +#define SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD_SIZE_OFF(S, NS, F, NF, SIZE, OFF, \ + TF) \ + do { \ + if (type == BPF_WRITE) { \ + SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \ + TF); \ + } else { \ + SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \ + S, NS, F, NF, SIZE, OFF); \ + } \ + } while (0) + +#define SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD(S, NS, F, NF, TF) \ + SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD_SIZE_OFF( \ + S, NS, F, NF, BPF_FIELD_SIZEOF(NS, NF), 0, TF) + +static u32 sock_addr_convert_ctx_access(enum bpf_access_type type, + const struct bpf_insn *si, + struct bpf_insn *insn_buf, + struct bpf_prog *prog, u32 *target_size) +{ + struct bpf_insn *insn = insn_buf; + int off; + + switch (si->off) { + case offsetof(struct bpf_sock_addr, user_family): + SOCK_ADDR_LOAD_NESTED_FIELD(struct bpf_sock_addr_kern, + struct sockaddr, uaddr, sa_family); + break; + + case offsetof(struct bpf_sock_addr, user_ip4): + SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD_SIZE_OFF( + struct bpf_sock_addr_kern, struct sockaddr_in, uaddr, + sin_addr, BPF_SIZE(si->code), 0, tmp_reg); + break; + + case bpf_ctx_range_till(struct bpf_sock_addr, user_ip6[0], user_ip6[3]): + off = si->off; + off -= offsetof(struct bpf_sock_addr, user_ip6[0]); + SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD_SIZE_OFF( + struct bpf_sock_addr_kern, struct sockaddr_in6, uaddr, + sin6_addr.s6_addr32[0], BPF_SIZE(si->code), off, + tmp_reg); + break; + + case offsetof(struct bpf_sock_addr, user_port): + /* To get port we need to know sa_family first and then treat + * sockaddr as either sockaddr_in or sockaddr_in6. + * Though we can simplify since port field has same offset and + * size in both structures. + * Here we check this invariant and use just one of the + * structures if it's true. + */ + BUILD_BUG_ON(offsetof(struct sockaddr_in, sin_port) != + offsetof(struct sockaddr_in6, sin6_port)); + BUILD_BUG_ON(FIELD_SIZEOF(struct sockaddr_in, sin_port) != + FIELD_SIZEOF(struct sockaddr_in6, sin6_port)); + SOCK_ADDR_LOAD_OR_STORE_NESTED_FIELD(struct bpf_sock_addr_kern, + struct sockaddr_in6, uaddr, + sin6_port, tmp_reg); + break; + + case offsetof(struct bpf_sock_addr, family): + SOCK_ADDR_LOAD_NESTED_FIELD(struct bpf_sock_addr_kern, + struct sock, sk, sk_family); + break; + + case offsetof(struct bpf_sock_addr, type): + SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( + struct bpf_sock_addr_kern, struct sock, sk, + __sk_flags_offset, BPF_W, 0); + *insn++ = BPF_ALU32_IMM(BPF_AND, si->dst_reg, SK_FL_TYPE_MASK); + *insn++ = BPF_ALU32_IMM(BPF_RSH, si->dst_reg, SK_FL_TYPE_SHIFT); + break; + + case offsetof(struct bpf_sock_addr, protocol): + SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( + struct bpf_sock_addr_kern, struct sock, sk, + __sk_flags_offset, BPF_W, 0); + *insn++ = BPF_ALU32_IMM(BPF_AND, si->dst_reg, SK_FL_PROTO_MASK); + *insn++ = BPF_ALU32_IMM(BPF_RSH, si->dst_reg, + SK_FL_PROTO_SHIFT); + break; + } + + return insn - insn_buf; +} + static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, const struct bpf_insn *si, struct bpf_insn *insn_buf, @@ -5181,6 +5404,15 @@ const struct bpf_verifier_ops cg_sock_verifier_ops = { const struct bpf_prog_ops cg_sock_prog_ops = { }; +const struct bpf_verifier_ops cg_sock_addr_verifier_ops = { + .get_func_proto = sock_addr_func_proto, + .is_valid_access = sock_addr_is_valid_access, + .convert_ctx_access = sock_addr_convert_ctx_access, +}; + +const struct bpf_prog_ops cg_sock_addr_prog_ops = { +}; + const struct bpf_verifier_ops sock_ops_verifier_ops = { .get_func_proto = sock_ops_func_proto, .is_valid_access = sock_ops_is_valid_access, diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index e8c7fad8c329..2dec266507dc 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -450,6 +450,13 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) if (addr_len < sizeof(struct sockaddr_in)) goto out; + /* BPF prog is run before any checks are done so that if the prog + * changes context in a wrong way it will be caught. + */ + err = BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr); + if (err) + goto out; + if (addr->sin_family != AF_INET) { /* Compatibility games : accept AF_UNSPEC (mapped to AF_INET) * only if s_addr is INADDR_ANY. diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index dbbe04018813..fa24e3f06ac6 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -295,6 +295,13 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) if (addr_len < SIN6_LEN_RFC2133) return -EINVAL; + /* BPF prog is run before any checks are done so that if the prog + * changes context in a wrong way it will be caught. + */ + err = BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr); + if (err) + return err; + if (addr->sin6_family != AF_INET6) return -EAFNOSUPPORT; -- cgit v1.2.3 From d74bad4e74ee373787a9ae24197c17b7cdc428d5 Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Fri, 30 Mar 2018 15:08:05 -0700 Subject: bpf: Hooks for sys_connect == The problem == See description of the problem in the initial patch of this patch set. == The solution == The patch provides much more reliable in-kernel solution for the 2nd part of the problem: making outgoing connecttion from desired IP. It adds new attach types `BPF_CGROUP_INET4_CONNECT` and `BPF_CGROUP_INET6_CONNECT` for program type `BPF_PROG_TYPE_CGROUP_SOCK_ADDR` that can be used to override both source and destination of a connection at connect(2) time. Local end of connection can be bound to desired IP using newly introduced BPF-helper `bpf_bind()`. It allows to bind to only IP though, and doesn't support binding to port, i.e. leverages `IP_BIND_ADDRESS_NO_PORT` socket option. There are two reasons for this: * looking for a free port is expensive and can affect performance significantly; * there is no use-case for port. As for remote end (`struct sockaddr *` passed by user), both parts of it can be overridden, remote IP and remote port. It's useful if an application inside cgroup wants to connect to another application inside same cgroup or to itself, but knows nothing about IP assigned to the cgroup. Support is added for IPv4 and IPv6, for TCP and UDP. IPv4 and IPv6 have separate attach types for same reason as sys_bind hooks, i.e. to prevent reading from / writing to e.g. user_ip6 fields when user passes sockaddr_in since it'd be out-of-bound. == Implementation notes == The patch introduces new field in `struct proto`: `pre_connect` that is a pointer to a function with same signature as `connect` but is called before it. The reason is in some cases BPF hooks should be called way before control is passed to `sk->sk_prot->connect`. Specifically `inet_dgram_connect` autobinds socket before calling `sk->sk_prot->connect` and there is no way to call `bpf_bind()` from hooks from e.g. `ip4_datagram_connect` or `ip6_datagram_connect` since it'd cause double-bind. On the other hand `proto.pre_connect` provides a flexible way to add BPF hooks for connect only for necessary `proto` and call them at desired time before `connect`. Since `bpf_bind()` is allowed to bind only to IP and autobind in `inet_dgram_connect` binds only port there is no chance of double-bind. bpf_bind() sets `force_bind_address_no_port` to bind to only IP despite of value of `bind_address_no_port` socket field. bpf_bind() sets `with_lock` to `false` when calling to __inet_bind() and __inet6_bind() since all call-sites, where bpf_bind() is called, already hold socket lock. Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- include/linux/bpf-cgroup.h | 31 +++++++++++++++++++++++++ include/net/addrconf.h | 7 ++++++ include/net/sock.h | 3 +++ include/net/udp.h | 1 + include/uapi/linux/bpf.h | 12 +++++++++- kernel/bpf/syscall.c | 8 +++++++ net/core/filter.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++ net/ipv4/af_inet.c | 13 +++++++++++ net/ipv4/tcp_ipv4.c | 16 +++++++++++++ net/ipv4/udp.c | 14 ++++++++++++ net/ipv6/af_inet6.c | 5 ++++ net/ipv6/tcp_ipv6.c | 16 +++++++++++++ net/ipv6/udp.c | 20 ++++++++++++++++ 13 files changed, 202 insertions(+), 1 deletion(-) (limited to 'kernel/bpf/syscall.c') diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 67dc4a6471ad..c6ab295e6dcb 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -116,12 +116,38 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, __ret; \ }) +#define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, type) \ +({ \ + int __ret = 0; \ + if (cgroup_bpf_enabled) { \ + lock_sock(sk); \ + __ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type); \ + release_sock(sk); \ + } \ + __ret; \ +}) + #define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) \ BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET4_BIND) #define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) \ BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET6_BIND) +#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (cgroup_bpf_enabled && \ + sk->sk_prot->pre_connect) + +#define BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr) \ + BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET4_CONNECT) + +#define BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr) \ + BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET6_CONNECT) + +#define BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr) \ + BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET4_CONNECT) + +#define BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr) \ + BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET6_CONNECT) + #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) \ ({ \ int __ret = 0; \ @@ -151,11 +177,16 @@ struct cgroup_bpf {}; static inline void cgroup_bpf_put(struct cgroup *cgrp) {} static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } +#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0) #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; }) #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type,major,minor,access) ({ 0; }) diff --git a/include/net/addrconf.h b/include/net/addrconf.h index 132e5b95167a..378d601258be 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -231,6 +231,13 @@ struct ipv6_stub { }; extern const struct ipv6_stub *ipv6_stub __read_mostly; +/* A stub used by bpf helpers. Similarly ugly as ipv6_stub */ +struct ipv6_bpf_stub { + int (*inet6_bind)(struct sock *sk, struct sockaddr *uaddr, int addr_len, + bool force_bind_address_no_port, bool with_lock); +}; +extern const struct ipv6_bpf_stub *ipv6_bpf_stub __read_mostly; + /* * identify MLD packets for MLD filter exceptions */ diff --git a/include/net/sock.h b/include/net/sock.h index b8ff435fa96e..49bd2c1796b0 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1026,6 +1026,9 @@ static inline void sk_prot_clear_nulls(struct sock *sk, int size) struct proto { void (*close)(struct sock *sk, long timeout); + int (*pre_connect)(struct sock *sk, + struct sockaddr *uaddr, + int addr_len); int (*connect)(struct sock *sk, struct sockaddr *uaddr, int addr_len); diff --git a/include/net/udp.h b/include/net/udp.h index 850a8e581cce..0676b272f6ac 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -273,6 +273,7 @@ void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); int udp_rcv(struct sk_buff *skb); int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); int udp_init_sock(struct sock *sk); +int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); int __udp_disconnect(struct sock *sk, int flags); int udp_disconnect(struct sock *sk, int flags); __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ce3e69e3c793..77afaf1ba556 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -150,6 +150,8 @@ enum bpf_attach_type { BPF_SK_MSG_VERDICT, BPF_CGROUP_INET4_BIND, BPF_CGROUP_INET6_BIND, + BPF_CGROUP_INET4_CONNECT, + BPF_CGROUP_INET6_CONNECT, __MAX_BPF_ATTACH_TYPE }; @@ -744,6 +746,13 @@ union bpf_attr { * @flags: reserved for future use * Return: SK_PASS * + * int bpf_bind(ctx, addr, addr_len) + * Bind socket to address. Only binding to IP is supported, no port can be + * set in addr. + * @ctx: pointer to context of type bpf_sock_addr + * @addr: pointer to struct sockaddr to bind socket to + * @addr_len: length of sockaddr structure + * Return: 0 on success or negative error code */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -809,7 +818,8 @@ union bpf_attr { FN(msg_redirect_map), \ FN(msg_apply_bytes), \ FN(msg_cork_bytes), \ - FN(msg_pull_data), + FN(msg_pull_data), \ + FN(bind), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2cad66a4cacb..cf1b29bc0ab8 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1180,6 +1180,8 @@ bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type, switch (expected_attach_type) { case BPF_CGROUP_INET4_BIND: case BPF_CGROUP_INET6_BIND: + case BPF_CGROUP_INET4_CONNECT: + case BPF_CGROUP_INET6_CONNECT: return 0; default: return -EINVAL; @@ -1491,6 +1493,8 @@ static int bpf_prog_attach(const union bpf_attr *attr) break; case BPF_CGROUP_INET4_BIND: case BPF_CGROUP_INET6_BIND: + case BPF_CGROUP_INET4_CONNECT: + case BPF_CGROUP_INET6_CONNECT: ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR; break; case BPF_CGROUP_SOCK_OPS: @@ -1557,6 +1561,8 @@ static int bpf_prog_detach(const union bpf_attr *attr) break; case BPF_CGROUP_INET4_BIND: case BPF_CGROUP_INET6_BIND: + case BPF_CGROUP_INET4_CONNECT: + case BPF_CGROUP_INET6_CONNECT: ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR; break; case BPF_CGROUP_SOCK_OPS: @@ -1610,6 +1616,8 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_CGROUP_INET_SOCK_CREATE: case BPF_CGROUP_INET4_BIND: case BPF_CGROUP_INET6_BIND: + case BPF_CGROUP_INET4_CONNECT: + case BPF_CGROUP_INET6_CONNECT: case BPF_CGROUP_SOCK_OPS: case BPF_CGROUP_DEVICE: break; diff --git a/net/core/filter.c b/net/core/filter.c index c08e5b121558..bdb9cadd4d27 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include #include @@ -3656,6 +3657,52 @@ static const struct bpf_func_proto bpf_sock_ops_cb_flags_set_proto = { .arg2_type = ARG_ANYTHING, }; +const struct ipv6_bpf_stub *ipv6_bpf_stub __read_mostly; +EXPORT_SYMBOL_GPL(ipv6_bpf_stub); + +BPF_CALL_3(bpf_bind, struct bpf_sock_addr_kern *, ctx, struct sockaddr *, addr, + int, addr_len) +{ +#ifdef CONFIG_INET + struct sock *sk = ctx->sk; + int err; + + /* Binding to port can be expensive so it's prohibited in the helper. + * Only binding to IP is supported. + */ + err = -EINVAL; + if (addr->sa_family == AF_INET) { + if (addr_len < sizeof(struct sockaddr_in)) + return err; + if (((struct sockaddr_in *)addr)->sin_port != htons(0)) + return err; + return __inet_bind(sk, addr, addr_len, true, false); +#if IS_ENABLED(CONFIG_IPV6) + } else if (addr->sa_family == AF_INET6) { + if (addr_len < SIN6_LEN_RFC2133) + return err; + if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0)) + return err; + /* ipv6_bpf_stub cannot be NULL, since it's called from + * bpf_cgroup_inet6_connect hook and ipv6 is already loaded + */ + return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len, true, false); +#endif /* CONFIG_IPV6 */ + } +#endif /* CONFIG_INET */ + + return -EAFNOSUPPORT; +} + +static const struct bpf_func_proto bpf_bind_proto = { + .func = bpf_bind, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + static const struct bpf_func_proto * bpf_base_func_proto(enum bpf_func_id func_id) { @@ -3707,6 +3754,14 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) */ case BPF_FUNC_get_current_uid_gid: return &bpf_get_current_uid_gid_proto; + case BPF_FUNC_bind: + switch (prog->expected_attach_type) { + case BPF_CGROUP_INET4_CONNECT: + case BPF_CGROUP_INET6_CONNECT: + return &bpf_bind_proto; + default: + return NULL; + } default: return bpf_base_func_proto(func_id); } @@ -4213,6 +4268,7 @@ static bool sock_addr_is_valid_access(int off, int size, case bpf_ctx_range(struct bpf_sock_addr, user_ip4): switch (prog->expected_attach_type) { case BPF_CGROUP_INET4_BIND: + case BPF_CGROUP_INET4_CONNECT: break; default: return false; @@ -4221,6 +4277,7 @@ static bool sock_addr_is_valid_access(int off, int size, case bpf_ctx_range_till(struct bpf_sock_addr, user_ip6[0], user_ip6[3]): switch (prog->expected_attach_type) { case BPF_CGROUP_INET6_BIND: + case BPF_CGROUP_INET6_CONNECT: break; default: return false; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index e203a39d6988..488fe26ac8e5 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -547,12 +547,19 @@ int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags) { struct sock *sk = sock->sk; + int err; if (addr_len < sizeof(uaddr->sa_family)) return -EINVAL; if (uaddr->sa_family == AF_UNSPEC) return sk->sk_prot->disconnect(sk, flags); + if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) { + err = sk->sk_prot->pre_connect(sk, uaddr, addr_len); + if (err) + return err; + } + if (!inet_sk(sk)->inet_num && inet_autobind(sk)) return -EAGAIN; return sk->sk_prot->connect(sk, uaddr, addr_len); @@ -633,6 +640,12 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr, if (sk->sk_state != TCP_CLOSE) goto out; + if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) { + err = sk->sk_prot->pre_connect(sk, uaddr, addr_len); + if (err) + goto out; + } + err = sk->sk_prot->connect(sk, uaddr, addr_len); if (err < 0) goto out; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 2c6aec2643e8..3c11d992d784 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -140,6 +140,21 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) } EXPORT_SYMBOL_GPL(tcp_twsk_unique); +static int tcp_v4_pre_connect(struct sock *sk, struct sockaddr *uaddr, + int addr_len) +{ + /* This check is replicated from tcp_v4_connect() and intended to + * prevent BPF program called below from accessing bytes that are out + * of the bound specified by user in addr_len. + */ + if (addr_len < sizeof(struct sockaddr_in)) + return -EINVAL; + + sock_owned_by_me(sk); + + return BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr); +} + /* This will initiate an outgoing connection. */ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) { @@ -2409,6 +2424,7 @@ struct proto tcp_prot = { .name = "TCP", .owner = THIS_MODULE, .close = tcp_close, + .pre_connect = tcp_v4_pre_connect, .connect = tcp_v4_connect, .disconnect = tcp_disconnect, .accept = inet_csk_accept, diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 908fc02fb4f8..9c6c77fec963 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1658,6 +1658,19 @@ csum_copy_err: goto try_again; } +int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) +{ + /* This check is replicated from __ip4_datagram_connect() and + * intended to prevent BPF program called below from accessing bytes + * that are out of the bound specified by user in addr_len. + */ + if (addr_len < sizeof(struct sockaddr_in)) + return -EINVAL; + + return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr); +} +EXPORT_SYMBOL(udp_pre_connect); + int __udp_disconnect(struct sock *sk, int flags) { struct inet_sock *inet = inet_sk(sk); @@ -2530,6 +2543,7 @@ struct proto udp_prot = { .name = "UDP", .owner = THIS_MODULE, .close = udp_lib_close, + .pre_connect = udp_pre_connect, .connect = ip4_datagram_connect, .disconnect = udp_disconnect, .ioctl = udp_ioctl, diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 13110bee5c14..566cec0e0a44 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -887,6 +887,10 @@ static const struct ipv6_stub ipv6_stub_impl = { .nd_tbl = &nd_tbl, }; +static const struct ipv6_bpf_stub ipv6_bpf_stub_impl = { + .inet6_bind = __inet6_bind, +}; + static int __init inet6_init(void) { struct list_head *r; @@ -1043,6 +1047,7 @@ static int __init inet6_init(void) /* ensure that ipv6 stubs are visible only after ipv6 is ready */ wmb(); ipv6_stub = &ipv6_stub_impl; + ipv6_bpf_stub = &ipv6_bpf_stub_impl; out: return err; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 5425d7b100ee..6469b741cf5a 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -117,6 +117,21 @@ static u32 tcp_v6_init_ts_off(const struct net *net, const struct sk_buff *skb) ipv6_hdr(skb)->saddr.s6_addr32); } +static int tcp_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr, + int addr_len) +{ + /* This check is replicated from tcp_v6_connect() and intended to + * prevent BPF program called below from accessing bytes that are out + * of the bound specified by user in addr_len. + */ + if (addr_len < SIN6_LEN_RFC2133) + return -EINVAL; + + sock_owned_by_me(sk); + + return BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr); +} + static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) { @@ -1925,6 +1940,7 @@ struct proto tcpv6_prot = { .name = "TCPv6", .owner = THIS_MODULE, .close = tcp_close, + .pre_connect = tcp_v6_pre_connect, .connect = tcp_v6_connect, .disconnect = tcp_disconnect, .accept = inet_csk_accept, diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index ad30f5e31969..6861ed479469 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -957,6 +957,25 @@ static void udp_v6_flush_pending_frames(struct sock *sk) } } +static int udpv6_pre_connect(struct sock *sk, struct sockaddr *uaddr, + int addr_len) +{ + /* The following checks are replicated from __ip6_datagram_connect() + * and intended to prevent BPF program called below from accessing + * bytes that are out of the bound specified by user in addr_len. + */ + if (uaddr->sa_family == AF_INET) { + if (__ipv6_only_sock(sk)) + return -EAFNOSUPPORT; + return udp_pre_connect(sk, uaddr, addr_len); + } + + if (addr_len < SIN6_LEN_RFC2133) + return -EINVAL; + + return BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr); +} + /** * udp6_hwcsum_outgoing - handle outgoing HW checksumming * @sk: socket we are sending on @@ -1512,6 +1531,7 @@ struct proto udpv6_prot = { .name = "UDPv6", .owner = THIS_MODULE, .close = udp_lib_close, + .pre_connect = udpv6_pre_connect, .connect = ip6_datagram_connect, .disconnect = udp_disconnect, .ioctl = udp_ioctl, -- cgit v1.2.3 From aac3fc320d9404f2665a8b1249dc3170d5fa3caf Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Fri, 30 Mar 2018 15:08:07 -0700 Subject: bpf: Post-hooks for sys_bind "Post-hooks" are hooks that are called right before returning from sys_bind. At this time IP and port are already allocated and no further changes to `struct sock` can happen before returning from sys_bind but BPF program has a chance to inspect the socket and change sys_bind result. Specifically it can e.g. inspect what port was allocated and if it doesn't satisfy some policy, BPF program can force sys_bind to fail and return EPERM to user. Another example of usage is recording the IP:port pair to some map to use it in later calls to sys_connect. E.g. if some TCP server inside cgroup was bound to some IP:port_n, it can be recorded to a map. And later when some TCP client inside same cgroup is trying to connect to 127.0.0.1:port_n, BPF hook for sys_connect can override the destination and connect application to IP:port_n instead of 127.0.0.1:port_n. That helps forcing all applications inside a cgroup to use desired IP and not break those applications if they e.g. use localhost to communicate between each other. == Implementation details == Post-hooks are implemented as two new attach types `BPF_CGROUP_INET4_POST_BIND` and `BPF_CGROUP_INET6_POST_BIND` for existing prog type `BPF_PROG_TYPE_CGROUP_SOCK`. Separate attach types for IPv4 and IPv6 are introduced to avoid access to IPv6 field in `struct sock` from `inet_bind()` and to IPv4 field from `inet6_bind()` since those fields might not make sense in such cases. Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- include/linux/bpf-cgroup.h | 16 +++++-- include/uapi/linux/bpf.h | 11 +++++ kernel/bpf/syscall.c | 43 +++++++++++++++++ net/core/filter.c | 116 +++++++++++++++++++++++++++++++++++++++------ net/ipv4/af_inet.c | 18 ++++--- net/ipv6/af_inet6.c | 21 +++++--- 6 files changed, 195 insertions(+), 30 deletions(-) (limited to 'kernel/bpf/syscall.c') diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index c6ab295e6dcb..30d15e64b993 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -98,16 +98,24 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, __ret; \ }) -#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \ +#define BPF_CGROUP_RUN_SK_PROG(sk, type) \ ({ \ int __ret = 0; \ if (cgroup_bpf_enabled) { \ - __ret = __cgroup_bpf_run_filter_sk(sk, \ - BPF_CGROUP_INET_SOCK_CREATE); \ + __ret = __cgroup_bpf_run_filter_sk(sk, type); \ } \ __ret; \ }) +#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_CREATE) + +#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET4_POST_BIND) + +#define BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET6_POST_BIND) + #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, type) \ ({ \ int __ret = 0; \ @@ -183,6 +191,8 @@ static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr) ({ 0; }) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 77afaf1ba556..c5ec89732a8d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -152,6 +152,8 @@ enum bpf_attach_type { BPF_CGROUP_INET6_BIND, BPF_CGROUP_INET4_CONNECT, BPF_CGROUP_INET6_CONNECT, + BPF_CGROUP_INET4_POST_BIND, + BPF_CGROUP_INET6_POST_BIND, __MAX_BPF_ATTACH_TYPE }; @@ -948,6 +950,15 @@ struct bpf_sock { __u32 protocol; __u32 mark; __u32 priority; + __u32 src_ip4; /* Allows 1,2,4-byte read. + * Stored in network byte order. + */ + __u32 src_ip6[4]; /* Allows 1,2,4-byte read. + * Stored in network byte order. + */ + __u32 src_port; /* Allows 4-byte read. + * Stored in host byte order + */ }; #define XDP_PACKET_HEADROOM 256 diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index cf1b29bc0ab8..0244973ee544 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1171,11 +1171,46 @@ struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type, } EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev); +/* Initially all BPF programs could be loaded w/o specifying + * expected_attach_type. Later for some of them specifying expected_attach_type + * at load time became required so that program could be validated properly. + * Programs of types that are allowed to be loaded both w/ and w/o (for + * backward compatibility) expected_attach_type, should have the default attach + * type assigned to expected_attach_type for the latter case, so that it can be + * validated later at attach time. + * + * bpf_prog_load_fixup_attach_type() sets expected_attach_type in @attr if + * prog type requires it but has some attach types that have to be backward + * compatible. + */ +static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr) +{ + switch (attr->prog_type) { + case BPF_PROG_TYPE_CGROUP_SOCK: + /* Unfortunately BPF_ATTACH_TYPE_UNSPEC enumeration doesn't + * exist so checking for non-zero is the way to go here. + */ + if (!attr->expected_attach_type) + attr->expected_attach_type = + BPF_CGROUP_INET_SOCK_CREATE; + break; + } +} + static int bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type, enum bpf_attach_type expected_attach_type) { switch (prog_type) { + case BPF_PROG_TYPE_CGROUP_SOCK: + switch (expected_attach_type) { + case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET4_POST_BIND: + case BPF_CGROUP_INET6_POST_BIND: + return 0; + default: + return -EINVAL; + } case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: switch (expected_attach_type) { case BPF_CGROUP_INET4_BIND: @@ -1195,6 +1230,7 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, enum bpf_attach_type attach_type) { switch (prog->type) { + case BPF_PROG_TYPE_CGROUP_SOCK: case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: return attach_type == prog->expected_attach_type ? 0 : -EINVAL; default: @@ -1240,6 +1276,7 @@ static int bpf_prog_load(union bpf_attr *attr) !capable(CAP_SYS_ADMIN)) return -EPERM; + bpf_prog_load_fixup_attach_type(attr); if (bpf_prog_load_check_attach_type(type, attr->expected_attach_type)) return -EINVAL; @@ -1489,6 +1526,8 @@ static int bpf_prog_attach(const union bpf_attr *attr) ptype = BPF_PROG_TYPE_CGROUP_SKB; break; case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET4_POST_BIND: + case BPF_CGROUP_INET6_POST_BIND: ptype = BPF_PROG_TYPE_CGROUP_SOCK; break; case BPF_CGROUP_INET4_BIND: @@ -1557,6 +1596,8 @@ static int bpf_prog_detach(const union bpf_attr *attr) ptype = BPF_PROG_TYPE_CGROUP_SKB; break; case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET4_POST_BIND: + case BPF_CGROUP_INET6_POST_BIND: ptype = BPF_PROG_TYPE_CGROUP_SOCK; break; case BPF_CGROUP_INET4_BIND: @@ -1616,6 +1657,8 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_CGROUP_INET_SOCK_CREATE: case BPF_CGROUP_INET4_BIND: case BPF_CGROUP_INET6_BIND: + case BPF_CGROUP_INET4_POST_BIND: + case BPF_CGROUP_INET6_POST_BIND: case BPF_CGROUP_INET4_CONNECT: case BPF_CGROUP_INET6_CONNECT: case BPF_CGROUP_SOCK_OPS: diff --git a/net/core/filter.c b/net/core/filter.c index bdb9cadd4d27..d31aff93270d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4097,30 +4097,80 @@ static bool lwt_is_valid_access(int off, int size, return bpf_skb_is_valid_access(off, size, type, prog, info); } -static bool sock_filter_is_valid_access(int off, int size, - enum bpf_access_type type, - const struct bpf_prog *prog, - struct bpf_insn_access_aux *info) + +/* Attach type specific accesses */ +static bool __sock_filter_check_attach_type(int off, + enum bpf_access_type access_type, + enum bpf_attach_type attach_type) { - if (type == BPF_WRITE) { - switch (off) { - case offsetof(struct bpf_sock, bound_dev_if): - case offsetof(struct bpf_sock, mark): - case offsetof(struct bpf_sock, priority): - break; + switch (off) { + case offsetof(struct bpf_sock, bound_dev_if): + case offsetof(struct bpf_sock, mark): + case offsetof(struct bpf_sock, priority): + switch (attach_type) { + case BPF_CGROUP_INET_SOCK_CREATE: + goto full_access; + default: + return false; + } + case bpf_ctx_range(struct bpf_sock, src_ip4): + switch (attach_type) { + case BPF_CGROUP_INET4_POST_BIND: + goto read_only; + default: + return false; + } + case bpf_ctx_range_till(struct bpf_sock, src_ip6[0], src_ip6[3]): + switch (attach_type) { + case BPF_CGROUP_INET6_POST_BIND: + goto read_only; + default: + return false; + } + case bpf_ctx_range(struct bpf_sock, src_port): + switch (attach_type) { + case BPF_CGROUP_INET4_POST_BIND: + case BPF_CGROUP_INET6_POST_BIND: + goto read_only; default: return false; } } +read_only: + return access_type == BPF_READ; +full_access: + return true; +} + +static bool __sock_filter_check_size(int off, int size, + struct bpf_insn_access_aux *info) +{ + const int size_default = sizeof(__u32); - if (off < 0 || off + size > sizeof(struct bpf_sock)) + switch (off) { + case bpf_ctx_range(struct bpf_sock, src_ip4): + case bpf_ctx_range_till(struct bpf_sock, src_ip6[0], src_ip6[3]): + bpf_ctx_record_field_size(info, size_default); + return bpf_ctx_narrow_access_ok(off, size, size_default); + } + + return size == size_default; +} + +static bool sock_filter_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + if (off < 0 || off >= sizeof(struct bpf_sock)) return false; - /* The verifier guarantees that size > 0. */ if (off % size != 0) return false; - if (size != sizeof(__u32)) + if (!__sock_filter_check_attach_type(off, type, + prog->expected_attach_type)) + return false; + if (!__sock_filter_check_size(off, size, info)) return false; - return true; } @@ -4728,6 +4778,7 @@ static u32 sock_filter_convert_ctx_access(enum bpf_access_type type, struct bpf_prog *prog, u32 *target_size) { struct bpf_insn *insn = insn_buf; + int off; switch (si->off) { case offsetof(struct bpf_sock, bound_dev_if): @@ -4783,6 +4834,43 @@ static u32 sock_filter_convert_ctx_access(enum bpf_access_type type, *insn++ = BPF_ALU32_IMM(BPF_AND, si->dst_reg, SK_FL_PROTO_MASK); *insn++ = BPF_ALU32_IMM(BPF_RSH, si->dst_reg, SK_FL_PROTO_SHIFT); break; + + case offsetof(struct bpf_sock, src_ip4): + *insn++ = BPF_LDX_MEM( + BPF_SIZE(si->code), si->dst_reg, si->src_reg, + bpf_target_off(struct sock_common, skc_rcv_saddr, + FIELD_SIZEOF(struct sock_common, + skc_rcv_saddr), + target_size)); + break; + + case bpf_ctx_range_till(struct bpf_sock, src_ip6[0], src_ip6[3]): +#if IS_ENABLED(CONFIG_IPV6) + off = si->off; + off -= offsetof(struct bpf_sock, src_ip6[0]); + *insn++ = BPF_LDX_MEM( + BPF_SIZE(si->code), si->dst_reg, si->src_reg, + bpf_target_off( + struct sock_common, + skc_v6_rcv_saddr.s6_addr32[0], + FIELD_SIZEOF(struct sock_common, + skc_v6_rcv_saddr.s6_addr32[0]), + target_size) + off); +#else + (void)off; + *insn++ = BPF_MOV32_IMM(si->dst_reg, 0); +#endif + break; + + case offsetof(struct bpf_sock, src_port): + *insn++ = BPF_LDX_MEM( + BPF_FIELD_SIZEOF(struct sock_common, skc_num), + si->dst_reg, si->src_reg, + bpf_target_off(struct sock_common, skc_num, + FIELD_SIZEOF(struct sock_common, + skc_num), + target_size)); + break; } return insn - insn_buf; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 488fe26ac8e5..142d4c35b493 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -519,12 +519,18 @@ int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len, inet->inet_saddr = 0; /* Use device */ /* Make sure we are allowed to bind here. */ - if ((snum || !(inet->bind_address_no_port || - force_bind_address_no_port)) && - sk->sk_prot->get_port(sk, snum)) { - inet->inet_saddr = inet->inet_rcv_saddr = 0; - err = -EADDRINUSE; - goto out_release_sock; + if (snum || !(inet->bind_address_no_port || + force_bind_address_no_port)) { + if (sk->sk_prot->get_port(sk, snum)) { + inet->inet_saddr = inet->inet_rcv_saddr = 0; + err = -EADDRINUSE; + goto out_release_sock; + } + err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk); + if (err) { + inet->inet_saddr = inet->inet_rcv_saddr = 0; + goto out_release_sock; + } } if (inet->inet_rcv_saddr) diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 566cec0e0a44..41f50472679d 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -412,13 +412,20 @@ int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len, sk->sk_ipv6only = 1; /* Make sure we are allowed to bind here. */ - if ((snum || !(inet->bind_address_no_port || - force_bind_address_no_port)) && - sk->sk_prot->get_port(sk, snum)) { - sk->sk_ipv6only = saved_ipv6only; - inet_reset_saddr(sk); - err = -EADDRINUSE; - goto out; + if (snum || !(inet->bind_address_no_port || + force_bind_address_no_port)) { + if (sk->sk_prot->get_port(sk, snum)) { + sk->sk_ipv6only = saved_ipv6only; + inet_reset_saddr(sk); + err = -EADDRINUSE; + goto out; + } + err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk); + if (err) { + sk->sk_ipv6only = saved_ipv6only; + inet_reset_saddr(sk); + goto out; + } } if (addr_type != IPV6_ADDR_ANY) -- cgit v1.2.3