diff options
| author | Eduard Zingerman <eddyz87@gmail.com> | 2024-12-10 05:10:53 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-12-10 19:24:57 +0100 |
| commit | 27e88bc4df1d80888fe1aaca786a7cc6e69587e2 (patch) | |
| tree | a6ff8b45f8f97835d1bfc0b4294c8f6792fa86b7 /kernel | |
| parent | bpf,perf: Fix invalid prog_array access in perf_event_detach_bpf_prog (diff) | |
| download | linux-27e88bc4df1d80888fe1aaca786a7cc6e69587e2.tar.xz linux-27e88bc4df1d80888fe1aaca786a7cc6e69587e2.zip | |
bpf: add find_containing_subprog() utility function
Add a utility function, looking for a subprogram containing a given
instruction index, rewrite find_subprog() to use this function.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20241210041100.1898468-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 01fbef9576e0..277c1892bb9a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2597,16 +2597,36 @@ static int cmp_subprogs(const void *a, const void *b) ((struct bpf_subprog_info *)b)->start; } +/* Find subprogram that contains instruction at 'off' */ +static struct bpf_subprog_info *find_containing_subprog(struct bpf_verifier_env *env, int off) +{ + struct bpf_subprog_info *vals = env->subprog_info; + int l, r, m; + + if (off >= env->prog->len || off < 0 || env->subprog_cnt == 0) + return NULL; + + l = 0; + r = env->subprog_cnt - 1; + while (l < r) { + m = l + (r - l + 1) / 2; + if (vals[m].start <= off) + l = m; + else + r = m - 1; + } + return &vals[l]; +} + +/* Find subprogram that starts exactly at 'off' */ static int find_subprog(struct bpf_verifier_env *env, int off) { struct bpf_subprog_info *p; - p = bsearch(&off, env->subprog_info, env->subprog_cnt, - sizeof(env->subprog_info[0]), cmp_subprogs); - if (!p) + p = find_containing_subprog(env, off); + if (!p || p->start != off) return -ENOENT; return p - env->subprog_info; - } static int add_subprog(struct bpf_verifier_env *env, int off) |