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authorDaniel Borkmann <daniel@iogearbox.net>2021-05-28 13:03:30 +0000
committerDaniel Borkmann <daniel@iogearbox.net>2021-06-14 23:06:00 +0200
commitd203b0fd863a2261e5d00b97f3d060c4c2a6db71 (patch)
tree79a6b6d2c2871044f0966d39cc875c76441f3b37 /kernel/bpf
parent11fc79fc9f2e395aa39fa5baccae62767c5d8280 (diff)
downloadlinux-d203b0fd863a2261e5d00b97f3d060c4c2a6db71.tar.bz2
bpf: Inherit expanded/patched seen count from old aux data
Instead of relying on current env->pass_cnt, use the seen count from the old aux data in adjust_insn_aux_data(), and expand it to the new range of patched instructions. This change is valid given we always expand 1:n with n>=1, so what applies to the old/original instruction needs to apply for the replacement as well. Not relying on env->pass_cnt is a prerequisite for a later change where we want to avoid marking an instruction seen when verified under speculative execution path. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Reviewed-by: Benedict Schlueter <benedict.schlueter@rub.de> Reviewed-by: Piotr Krysiuk <piotras@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/verifier.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 94ba5163d4c5..f93c7befb5dc 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11366,6 +11366,7 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env,
{
struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data;
struct bpf_insn *insn = new_prog->insnsi;
+ u32 old_seen = old_data[off].seen;
u32 prog_len;
int i;
@@ -11386,7 +11387,8 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env,
memcpy(new_data + off + cnt - 1, old_data + off,
sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
for (i = off; i < off + cnt - 1; i++) {
- new_data[i].seen = env->pass_cnt;
+ /* Expand insni[off]'s seen count to the patched range. */
+ new_data[i].seen = old_seen;
new_data[i].zext_dst = insn_has_def32(env, insn + i);
}
env->insn_aux_data = new_data;