diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 32d31fa67036..2ed17edf77f2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -17656,6 +17656,10 @@ bool bpf_get_call_summary(struct bpf_verifier_env *env, struct bpf_insn *call, * r0 = *(u64 *)(r10 - 8); r0 += r1; * r0 += r1; exit; * exit; + * + * Both uses of the marks assume that a pattern is entered at its first + * spill and thus executes as a unit, hence a pattern is not grown past + * an instruction targeted by a jump. */ static void mark_fastcall_pattern_for_call(struct bpf_verifier_env *env, struct bpf_subprog_info *subprog, @@ -17694,6 +17698,10 @@ static void mark_fastcall_pattern_for_call(struct bpf_verifier_env *env, for (i = 1, off = lowest_off; i <= ARRAY_SIZE(caller_saved); ++i, off += BPF_REG_SIZE) { if (insn_idx - i < 0 || insn_idx + i >= env->prog->len) break; + /* stx/ldx/call must not be a jump targets, a jump to the first stx is fine */ + if (bpf_is_jump_target(env, insn_idx - i + 1) || + bpf_is_jump_target(env, insn_idx + i)) + break; stx = &insns[insn_idx - i]; ldx = &insns[insn_idx + i]; /* must be a stack spill/fill pair */ |