From: Eduard Zingerman <eddyz87@gmail.com>
Date: Tue, 25 Feb 2025 00:38:38 +0000 (-0800)
Subject: bpf: abort verification if env->cur_state->loop_entry != NULL
X-Git-Tag: v6.15-rc1~98^2~50
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f3c2d243a36ef23be07bc2bce7c6a5cb6e07d9e3;p=thirdparty%2Fkernel%2Flinux.git

bpf: abort verification if env->cur_state->loop_entry != NULL

In addition to warning abort verification with -EFAULT.
If env->cur_state->loop_entry != NULL something is irrecoverably
buggy.

Fixes: bbbc02b7445e ("bpf: copy_verifier_state() should copy 'loop_entry' field")
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20250225003838.135319-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5c9b7464ec2c9..942c0d2df258a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19340,8 +19340,10 @@ process_bpf_exit:
 						return err;
 					break;
 				} else {
-					if (WARN_ON_ONCE(env->cur_state->loop_entry))
-						env->cur_state->loop_entry = NULL;
+					if (WARN_ON_ONCE(env->cur_state->loop_entry)) {
+						verbose(env, "verifier bug: env->cur_state->loop_entry != NULL\n");
+						return -EFAULT;
+					}
 					do_print_state = true;
 					continue;
 				}