summaryrefslogtreecommitdiff
path: root/kernel/bpf
diff options
context:
space:
mode:
authorAlexei Starovoitov <ast@kernel.org>2020-01-21 18:41:38 -0800
committerDaniel Borkmann <daniel@iogearbox.net>2020-01-22 12:09:02 +0100
commitf59bbfc2f6099e8655f9e8f585e10ffde17176d0 (patch)
tree0e3289384ee6ad1a13499afe74509574be73f27c /kernel/bpf
parent05d57f1793fb250c85028c9952c3720010baa853 (diff)
bpf: Fix error path under memory pressure
Restore the 'if (env->cur_state)' check that was incorrectly removed during code move. Under memory pressure env->cur_state can be freed and zeroed inside do_check(). Hence the check is necessary. Fixes: 51c39bb1d5d1 ("bpf: Introduce function-by-function verification") Reported-by: syzbot+b296579ba5015704d9fa@syzkaller.appspotmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200122024138.3385590-1-ast@kernel.org
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/verifier.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ca17dccc17ba..6defbec9eb62 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9594,8 +9594,13 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog)
ret = do_check(env);
out:
- free_verifier_state(env->cur_state, true);
- env->cur_state = NULL;
+ /* check for NULL is necessary, since cur_state can be freed inside
+ * do_check() under memory pressure.
+ */
+ if (env->cur_state) {
+ free_verifier_state(env->cur_state, true);
+ env->cur_state = NULL;
+ }
while (!pop_stack(env, NULL, NULL));
free_states(env);
if (ret)