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-rw-r--r--include/linux/bpf.h1
-rw-r--r--kernel/bpf/verifier.c4
-rw-r--r--kernel/trace/bpf_trace.c12
-rw-r--r--net/core/filter.c4
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c113
5 files changed, 116 insertions, 18 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 76c577281d78..e55e4255a210 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -78,6 +78,7 @@ enum bpf_arg_type {
* functions that access data on eBPF program stack
*/
ARG_PTR_TO_MEM, /* pointer to valid memory (stack, packet, map value) */
+ ARG_PTR_TO_MEM_OR_NULL, /* pointer to valid memory or NULL */
ARG_PTR_TO_UNINIT_MEM, /* pointer to memory does not need to be initialized,
* helper function must fill all bytes or clear
* them in error case.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index dd54d20ace2f..308b0638ec5d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1384,13 +1384,15 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
if (type != expected_type)
goto err_type;
} else if (arg_type == ARG_PTR_TO_MEM ||
+ arg_type == ARG_PTR_TO_MEM_OR_NULL ||
arg_type == ARG_PTR_TO_UNINIT_MEM) {
expected_type = PTR_TO_STACK;
/* One exception here. In case function allows for NULL to be
* passed in as argument, it's a SCALAR_VALUE type. Final test
* happens during stack boundary checking.
*/
- if (register_is_null(*reg))
+ if (register_is_null(*reg) &&
+ arg_type == ARG_PTR_TO_MEM_OR_NULL)
/* final test in check_stack_boundary() */;
else if (!type_is_pkt_pointer(type) &&
type != PTR_TO_MAP_VALUE &&
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a5580c670866..27d1f4ffa3de 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -78,16 +78,12 @@ EXPORT_SYMBOL_GPL(trace_call_bpf);
BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr)
{
- int ret = 0;
-
- if (unlikely(size == 0))
- goto out;
+ int ret;
ret = probe_kernel_read(dst, unsafe_ptr, size);
if (unlikely(ret < 0))
memset(dst, 0, size);
- out:
return ret;
}
@@ -407,7 +403,7 @@ static const struct bpf_func_proto bpf_perf_event_output_proto = {
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_PTR_TO_MEM,
- .arg5_type = ARG_CONST_SIZE,
+ .arg5_type = ARG_CONST_SIZE_OR_ZERO,
};
static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);
@@ -498,7 +494,7 @@ static const struct bpf_func_proto bpf_probe_read_str_proto = {
.gpl_only = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_UNINIT_MEM,
- .arg2_type = ARG_CONST_SIZE,
+ .arg2_type = ARG_CONST_SIZE_OR_ZERO,
.arg3_type = ARG_ANYTHING,
};
@@ -609,7 +605,7 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
.arg2_type = ARG_CONST_MAP_PTR,
.arg3_type = ARG_ANYTHING,
.arg4_type = ARG_PTR_TO_MEM,
- .arg5_type = ARG_CONST_SIZE,
+ .arg5_type = ARG_CONST_SIZE_OR_ZERO,
};
BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
diff --git a/net/core/filter.c b/net/core/filter.c
index 1afa17935954..6a85e67fafce 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1646,9 +1646,9 @@ static const struct bpf_func_proto bpf_csum_diff_proto = {
.gpl_only = false,
.pkt_access = true,
.ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_MEM,
+ .arg1_type = ARG_PTR_TO_MEM_OR_NULL,
.arg2_type = ARG_CONST_SIZE_OR_ZERO,
- .arg3_type = ARG_PTR_TO_MEM,
+ .arg3_type = ARG_PTR_TO_MEM_OR_NULL,
.arg4_type = ARG_CONST_SIZE_OR_ZERO,
.arg5_type = ARG_ANYTHING,
};
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 2a5267bef160..3c64f30cf63c 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -5631,7 +5631,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
{
- "helper access to variable memory: size = 0 allowed on NULL",
+ "helper access to variable memory: size = 0 allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_2, 0),
@@ -5645,7 +5645,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
- "helper access to variable memory: size > 0 not allowed on NULL",
+ "helper access to variable memory: size > 0 not allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_2, 0),
@@ -5663,7 +5663,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
- "helper access to variable memory: size = 0 allowed on != NULL stack pointer",
+ "helper access to variable memory: size = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
@@ -5680,7 +5680,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
- "helper access to variable memory: size = 0 allowed on != NULL map pointer",
+ "helper access to variable memory: size = 0 allowed on != NULL map pointer (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
@@ -5702,7 +5702,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
- "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer",
+ "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
@@ -5727,7 +5727,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
- "helper access to variable memory: size possible = 0 allowed on != NULL map pointer",
+ "helper access to variable memory: size possible = 0 allowed on != NULL map pointer (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
@@ -5750,7 +5750,7 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
- "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer",
+ "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer (ARG_PTR_TO_MEM_OR_NULL)",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
offsetof(struct __sk_buff, data)),
@@ -5772,6 +5772,105 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
+ "helper access to variable memory: size = 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_1, 0),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_EMIT_CALL(BPF_FUNC_probe_read),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 type=inv expected=fp",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
+ {
+ "helper access to variable memory: size > 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_1, 0),
+ BPF_MOV64_IMM(BPF_REG_2, 1),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_EMIT_CALL(BPF_FUNC_probe_read),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "R1 type=inv expected=fp",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
+ {
+ "helper access to variable memory: size = 0 allowed on != NULL stack pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_EMIT_CALL(BPF_FUNC_probe_read),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
+ {
+ "helper access to variable memory: size = 0 allowed on != NULL map pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_EMIT_CALL(BPF_FUNC_probe_read),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
+ {
+ "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_EMIT_CALL(BPF_FUNC_probe_read),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
+ {
+ "helper access to variable memory: size possible = 0 allowed on != NULL map pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 2),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_EMIT_CALL(BPF_FUNC_probe_read),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
+ {
"helper access to variable memory: 8 bytes leak",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
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