diff options
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 10 | ||||
| -rw-r--r-- | include/linux/bpf.h | 11 | ||||
| -rw-r--r-- | include/linux/kprobes.h | 1 | ||||
| -rw-r--r-- | include/linux/module.h | 5 | ||||
| -rw-r--r-- | kernel/kprobes.c | 163 | ||||
| -rw-r--r-- | kernel/module.c | 6 |
6 files changed, 195 insertions, 1 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index ee8b707d9fa9..a2e8582d094a 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -136,6 +136,15 @@ #define KPROBE_BLACKLIST() #endif +#ifdef CONFIG_BPF_KPROBE_OVERRIDE +#define ERROR_INJECT_LIST() . = ALIGN(8); \ + VMLINUX_SYMBOL(__start_kprobe_error_inject_list) = .; \ + KEEP(*(_kprobe_error_inject_list)) \ + VMLINUX_SYMBOL(__stop_kprobe_error_inject_list) = .; +#else +#define ERROR_INJECT_LIST() +#endif + #ifdef CONFIG_EVENT_TRACING #define FTRACE_EVENTS() . = ALIGN(8); \ VMLINUX_SYMBOL(__start_ftrace_events) = .; \ @@ -564,6 +573,7 @@ FTRACE_EVENTS() \ TRACE_SYSCALLS() \ KPROBE_BLACKLIST() \ + ERROR_INJECT_LIST() \ MEM_DISCARD(init.rodata) \ CLK_OF_TABLES() \ RESERVEDMEM_OF_TABLES() \ diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f812ac508e9f..93e15b9d80c7 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -580,4 +580,15 @@ extern const struct bpf_func_proto bpf_sock_map_update_proto; void bpf_user_rnd_init_once(void); u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); +#if defined(__KERNEL__) && !defined(__ASSEMBLY__) +#ifdef CONFIG_BPF_KPROBE_OVERRIDE +#define BPF_ALLOW_ERROR_INJECTION(fname) \ +static unsigned long __used \ + __attribute__((__section__("_kprobe_error_inject_list"))) \ + _eil_addr_##fname = (unsigned long)fname; +#else +#define BPF_ALLOW_ERROR_INJECTION(fname) +#endif +#endif + #endif /* _LINUX_BPF_H */ diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 9440a2fc8893..963fd364f3d6 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -271,6 +271,7 @@ extern bool arch_kprobe_on_func_entry(unsigned long offset); extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); extern bool within_kprobe_blacklist(unsigned long addr); +extern bool within_kprobe_error_injection_list(unsigned long addr); struct kprobe_insn_cache { struct mutex mutex; diff --git a/include/linux/module.h b/include/linux/module.h index c69b49abe877..548fa09fa806 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -475,6 +475,11 @@ struct module { ctor_fn_t *ctors; unsigned int num_ctors; #endif + +#ifdef CONFIG_BPF_KPROBE_OVERRIDE + unsigned int num_kprobe_ei_funcs; + unsigned long *kprobe_ei_funcs; +#endif } ____cacheline_aligned __randomize_layout; #ifndef MODULE_ARCH_INIT #define MODULE_ARCH_INIT {} diff --git a/kernel/kprobes.c b/kernel/kprobes.c index da2ccf142358..b4aab48ad258 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -83,6 +83,16 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) return &(kretprobe_table_locks[hash].lock); } +/* List of symbols that can be overriden for error injection. */ +static LIST_HEAD(kprobe_error_injection_list); +static DEFINE_MUTEX(kprobe_ei_mutex); +struct kprobe_ei_entry { + struct list_head list; + unsigned long start_addr; + unsigned long end_addr; + void *priv; +}; + /* Blacklist -- list of struct kprobe_blacklist_entry */ static LIST_HEAD(kprobe_blacklist); @@ -1394,6 +1404,17 @@ bool within_kprobe_blacklist(unsigned long addr) return false; } +bool within_kprobe_error_injection_list(unsigned long addr) +{ + struct kprobe_ei_entry *ent; + + list_for_each_entry(ent, &kprobe_error_injection_list, list) { + if (addr >= ent->start_addr && addr < ent->end_addr) + return true; + } + return false; +} + /* * If we have a symbol_name argument, look it up and add the offset field * to it. This way, we can specify a relative address to a symbol. @@ -2168,6 +2189,86 @@ static int __init populate_kprobe_blacklist(unsigned long *start, return 0; } +#ifdef CONFIG_BPF_KPROBE_OVERRIDE +/* Markers of the _kprobe_error_inject_list section */ +extern unsigned long __start_kprobe_error_inject_list[]; +extern unsigned long __stop_kprobe_error_inject_list[]; + +/* + * Lookup and populate the kprobe_error_injection_list. + * + * For safety reasons we only allow certain functions to be overriden with + * bpf_error_injection, so we need to populate the list of the symbols that have + * been marked as safe for overriding. + */ +static void populate_kprobe_error_injection_list(unsigned long *start, + unsigned long *end, + void *priv) +{ + unsigned long *iter; + struct kprobe_ei_entry *ent; + unsigned long entry, offset = 0, size = 0; + + mutex_lock(&kprobe_ei_mutex); + for (iter = start; iter < end; iter++) { + entry = arch_deref_entry_point((void *)*iter); + + if (!kernel_text_address(entry) || + !kallsyms_lookup_size_offset(entry, &size, &offset)) { + pr_err("Failed to find error inject entry at %p\n", + (void *)entry); + continue; + } + + ent = kmalloc(sizeof(*ent), GFP_KERNEL); + if (!ent) + break; + ent->start_addr = entry; + ent->end_addr = entry + size; + ent->priv = priv; + INIT_LIST_HEAD(&ent->list); + list_add_tail(&ent->list, &kprobe_error_injection_list); + } + mutex_unlock(&kprobe_ei_mutex); +} + +static void __init populate_kernel_kprobe_ei_list(void) +{ + populate_kprobe_error_injection_list(__start_kprobe_error_inject_list, + __stop_kprobe_error_inject_list, + NULL); +} + +static void module_load_kprobe_ei_list(struct module *mod) +{ + if (!mod->num_kprobe_ei_funcs) + return; + populate_kprobe_error_injection_list(mod->kprobe_ei_funcs, + mod->kprobe_ei_funcs + + mod->num_kprobe_ei_funcs, mod); +} + +static void module_unload_kprobe_ei_list(struct module *mod) +{ + struct kprobe_ei_entry *ent, *n; + if (!mod->num_kprobe_ei_funcs) + return; + + mutex_lock(&kprobe_ei_mutex); + list_for_each_entry_safe(ent, n, &kprobe_error_injection_list, list) { + if (ent->priv == mod) { + list_del_init(&ent->list); + kfree(ent); + } + } + mutex_unlock(&kprobe_ei_mutex); +} +#else +static inline void __init populate_kernel_kprobe_ei_list(void) {} +static inline void module_load_kprobe_ei_list(struct module *m) {} +static inline void module_unload_kprobe_ei_list(struct module *m) {} +#endif + /* Module notifier call back, checking kprobes on the module */ static int kprobes_module_callback(struct notifier_block *nb, unsigned long val, void *data) @@ -2178,6 +2279,11 @@ static int kprobes_module_callback(struct notifier_block *nb, unsigned int i; int checkcore = (val == MODULE_STATE_GOING); + if (val == MODULE_STATE_COMING) + module_load_kprobe_ei_list(mod); + else if (val == MODULE_STATE_GOING) + module_unload_kprobe_ei_list(mod); + if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) return NOTIFY_DONE; @@ -2240,6 +2346,8 @@ static int __init init_kprobes(void) pr_err("Please take care of using kprobes.\n"); } + populate_kernel_kprobe_ei_list(); + if (kretprobe_blacklist_size) { /* lookup the function address from its name */ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { @@ -2407,6 +2515,56 @@ static const struct file_operations debugfs_kprobe_blacklist_ops = { .release = seq_release, }; +/* + * kprobes/error_injection_list -- shows which functions can be overriden for + * error injection. + * */ +static void *kprobe_ei_seq_start(struct seq_file *m, loff_t *pos) +{ + mutex_lock(&kprobe_ei_mutex); + return seq_list_start(&kprobe_error_injection_list, *pos); +} + +static void kprobe_ei_seq_stop(struct seq_file *m, void *v) +{ + mutex_unlock(&kprobe_ei_mutex); +} + +static void *kprobe_ei_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + return seq_list_next(v, &kprobe_error_injection_list, pos); +} + +static int kprobe_ei_seq_show(struct seq_file *m, void *v) +{ + char buffer[KSYM_SYMBOL_LEN]; + struct kprobe_ei_entry *ent = + list_entry(v, struct kprobe_ei_entry, list); + + sprint_symbol(buffer, ent->start_addr); + seq_printf(m, "%s\n", buffer); + return 0; +} + +static const struct seq_operations kprobe_ei_seq_ops = { + .start = kprobe_ei_seq_start, + .next = kprobe_ei_seq_next, + .stop = kprobe_ei_seq_stop, + .show = kprobe_ei_seq_show, +}; + +static int kprobe_ei_open(struct inode *inode, struct file *filp) +{ + return seq_open(filp, &kprobe_ei_seq_ops); +} + +static const struct file_operations debugfs_kprobe_ei_ops = { + .open = kprobe_ei_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + static void arm_all_kprobes(void) { struct hlist_head *head; @@ -2548,6 +2706,11 @@ static int __init debugfs_kprobe_init(void) if (!file) goto error; + file = debugfs_create_file("error_injection_list", 0444, dir, NULL, + &debugfs_kprobe_ei_ops); + if (!file) + goto error; + return 0; error: diff --git a/kernel/module.c b/kernel/module.c index dea01ac9cb74..bd695bfdc5c4 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3118,7 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info) sizeof(*mod->ftrace_callsites), &mod->num_ftrace_callsites); #endif - +#ifdef CONFIG_BPF_KPROBE_OVERRIDE + mod->kprobe_ei_funcs = section_objs(info, "_kprobe_error_inject_list", + sizeof(*mod->kprobe_ei_funcs), + &mod->num_kprobe_ei_funcs); +#endif mod->extable = section_objs(info, "__ex_table", sizeof(*mod->extable), &mod->num_exentries); |
