From: Kohei Enju <enjuk@amazon.com>
To: <syzbot+a5964227adc0f904549c@syzkaller.appspotmail.com>
Cc: <andrii@kernel.org>, <ast@kernel.org>, <bpf@vger.kernel.org>,
<daniel@iogearbox.net>, <eddyz87@gmail.com>, <enjuk@amazon.com>,
<haoluo@google.com>, <iii@linux.ibm.com>,
<john.fastabend@gmail.com>, <jolsa@kernel.org>,
<kpsingh@kernel.org>, <linux-kernel@vger.kernel.org>,
<martin.lau@linux.dev>, <netdev@vger.kernel.org>,
<sdf@fomichev.me>, <song@kernel.org>,
<syzkaller-bugs@googlegroups.com>, <yepeilin@google.com>,
<yonghong.song@linux.dev>
Subject: Re: [syzbot] [bpf?] KASAN: slab-out-of-bounds Read in atomic_ptr_type_ok
Date: Sat, 15 Mar 2025 14:10:21 +0900 [thread overview]
Message-ID: <20250315051051.1532-1-enjuk@amazon.com> (raw)
In-Reply-To: <67d479a8.050a0220.1939a6.004e.GAE@google.com>
> syzbot found the following issue on:
>
> HEAD commit: f28214603dc6 Merge branch 'selftests-bpf-move-test_lwt_seg..
> git tree: bpf-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=15f84664580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1
> dashboard link: https://syzkaller.appspot.com/bug?extid=a5964227adc0f904549c
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16450ba8580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11f5fa54580000
#syz test
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7788,6 +7788,12 @@ static int check_atomic_rmw(struct bpf_verifier_env *env,
static int check_atomic_load(struct bpf_verifier_env *env,
struct bpf_insn *insn)
{
+ int err;
+
+ err = check_load_mem(env, insn, true, false, false, "atomic_load");
+ if (err)
+ return err;
+
if (!atomic_ptr_type_ok(env, insn->src_reg, insn)) {
verbose(env, "BPF_ATOMIC loads from R%d %s is not allowed\n",
insn->src_reg,
@@ -7795,12 +7801,18 @@ static int check_atomic_load(struct bpf_verifier_env *env,
return -EACCES;
}
- return check_load_mem(env, insn, true, false, false, "atomic_load");
+ return 0;
}
static int check_atomic_store(struct bpf_verifier_env *env,
struct bpf_insn *insn)
{
+ int err;
+
+ err = check_store_reg(env, insn, true);
+ if (err)
+ return err;
+
if (!atomic_ptr_type_ok(env, insn->dst_reg, insn)) {
verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
insn->dst_reg,
@@ -7808,7 +7820,7 @@ static int check_atomic_store(struct bpf_verifier_env *env,
return -EACCES;
}
- return check_store_reg(env, insn, true);
+ return 0;
}
static int check_atomic(struct bpf_verifier_env *env, struct bpf_insn *insn)
next prev parent reply other threads:[~2025-03-15 5:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-13 16:59 [syzbot] [bpf?] KASAN: slab-out-of-bounds Read in atomic_ptr_type_ok syzbot
2025-03-14 18:19 ` Kohei Enju
2025-03-14 18:47 ` syzbot
2025-03-15 5:10 ` Kohei Enju [this message]
2025-03-15 5:38 ` syzbot
2025-03-15 5:59 ` Kohei Enju
2025-03-15 6:27 ` syzbot
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