* [syzbot] [bpf?] [trace?] WARNING in format_decode (3)
@ 2023-11-21 22:43 syzbot
2023-11-22 0:19 ` [syzbot] " syzbot
[not found] ` <tencent_884D1773977426D9D3600371696883B6A405@qq.com>
0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2023-11-21 22:43 UTC (permalink / raw)
To: andrii, ast, bpf, daniel, davem, edumazet, haoluo, hawk,
john.fastabend, jolsa, kpsingh, kuba, linux-kernel,
linux-trace-kernel, martin.lau, martin.lau, mhiramat, netdev,
pabeni, rostedt, sdf, song, syzkaller-bugs, yhs, yonghong.song
Hello,
syzbot found the following issue on:
HEAD commit: 76df934c6d5f MAINTAINERS: Add netdev subsystem profile link
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10c2b667680000
kernel config: https://syzkaller.appspot.com/x/.config?x=84217b7fc4acdc59
dashboard link: https://syzkaller.appspot.com/bug?extid=e2c932aec5c8a6e1d31c
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12b2f668e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=171ea200e80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e271179068c6/disk-76df934c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b9523b3749bb/vmlinux-76df934c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6c1a888bade0/bzImage-76df934c.xz
The issue was bisected to:
commit 114039b342014680911c35bd6b72624180fd669a
Author: Stanislav Fomichev <sdf@google.com>
Date: Mon Nov 21 18:03:39 2022 +0000
bpf: Move skb->len == 0 checks into __bpf_redirect
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13d237b7680000
final oops: https://syzkaller.appspot.com/x/report.txt?x=103237b7680000
console output: https://syzkaller.appspot.com/x/log.txt?x=17d237b7680000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e2c932aec5c8a6e1d31c@syzkaller.appspotmail.com
Fixes: 114039b34201 ("bpf: Move skb->len == 0 checks into __bpf_redirect")
------------[ cut here ]------------
Please remove unsupported 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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [syzbot] [bpf?] [trace?] WARNING in format_decode (3)
2023-11-21 22:43 [syzbot] [bpf?] [trace?] WARNING in format_decode (3) syzbot
@ 2023-11-22 0:19 ` syzbot
[not found] ` <tencent_884D1773977426D9D3600371696883B6A405@qq.com>
1 sibling, 0 replies; 4+ messages in thread
From: syzbot @ 2023-11-22 0:19 UTC (permalink / raw)
To: linux-kernel
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.
***
Subject: [syzbot] [bpf?] [trace?] WARNING in format_decode (3)
Author: eadavis@qq.com
please test unsupported %? in format string
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git 76df934c6d5f
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index c9fdcc5cdce1..78258a822a5c 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -845,6 +845,9 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
{
struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
+ if (!skb->len)
+ return -EINVAL;
+
if (!__skb)
return 0;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net] bpf: test_run: fix WARNING in format_decode
[not found] ` <tencent_884D1773977426D9D3600371696883B6A405@qq.com>
@ 2023-11-22 5:28 ` Yonghong Song
2023-11-27 14:10 ` Daniel Borkmann
0 siblings, 1 reply; 4+ messages in thread
From: Yonghong Song @ 2023-11-22 5:28 UTC (permalink / raw)
To: Edward Adam Davis, syzbot+e2c932aec5c8a6e1d31c
Cc: andrii, ast, bpf, daniel, davem, edumazet, haoluo, hawk,
john.fastabend, jolsa, kpsingh, kuba, linux-kernel,
linux-trace-kernel, martin.lau, martin.lau, mhiramat, netdev,
pabeni, rostedt, sdf, song, syzkaller-bugs, yhs
On 11/21/23 7:50 PM, Edward Adam Davis wrote:
> Confirm that skb->len is not 0 to ensure that skb length is valid.
>
> Fixes: 114039b34201 ("bpf: Move skb->len == 0 checks into __bpf_redirect")
> Reported-by: syzbot+e2c932aec5c8a6e1d31c@syzkaller.appspotmail.com
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Stan, Could you take a look at this patch?
> ---
> net/bpf/test_run.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index c9fdcc5cdce1..78258a822a5c 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -845,6 +845,9 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
> {
> struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
>
> + if (!skb->len)
> + return -EINVAL;
> +
> if (!__skb)
> return 0;
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net] bpf: test_run: fix WARNING in format_decode
2023-11-22 5:28 ` [PATCH net] bpf: test_run: fix WARNING in format_decode Yonghong Song
@ 2023-11-27 14:10 ` Daniel Borkmann
0 siblings, 0 replies; 4+ messages in thread
From: Daniel Borkmann @ 2023-11-27 14:10 UTC (permalink / raw)
To: Yonghong Song, Edward Adam Davis, syzbot+e2c932aec5c8a6e1d31c
Cc: andrii, ast, bpf, davem, edumazet, haoluo, hawk, john.fastabend,
jolsa, kpsingh, kuba, linux-kernel, linux-trace-kernel,
martin.lau, martin.lau, mhiramat, netdev, pabeni, rostedt, sdf,
song, syzkaller-bugs, yhs
On 11/22/23 6:28 AM, Yonghong Song wrote:
> On 11/21/23 7:50 PM, Edward Adam Davis wrote:
>> Confirm that skb->len is not 0 to ensure that skb length is valid.
>>
>> Fixes: 114039b34201 ("bpf: Move skb->len == 0 checks into __bpf_redirect")
>> Reported-by: syzbot+e2c932aec5c8a6e1d31c@syzkaller.appspotmail.com
>> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
>
> Stan, Could you take a look at this patch?
I think this only papers over the bug.. also BPF selftests seem to break
with this change.
Looking again at the syzkaller trace :
[...]
Please remove unsupported %\0 in format string
WARNING: CPU: 0 PID: 5068 at lib/vsprintf.c:2675 format_decode+0xa03/0xba0 lib/vsprintf.c:2675
[...]
We need to fix bpf_bprintf_prepare() instead to reject invalid fmts such
as %0 and similar.
>> net/bpf/test_run.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
>> index c9fdcc5cdce1..78258a822a5c 100644
>> --- a/net/bpf/test_run.c
>> +++ b/net/bpf/test_run.c
>> @@ -845,6 +845,9 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
>> {
>> struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
>> + if (!skb->len)
>> + return -EINVAL;
>> +
>> if (!__skb)
>> return 0;
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-11-27 14:18 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2023-11-21 22:43 [syzbot] [bpf?] [trace?] WARNING in format_decode (3) syzbot
2023-11-22 0:19 ` [syzbot] " syzbot
[not found] ` <tencent_884D1773977426D9D3600371696883B6A405@qq.com>
2023-11-22 5:28 ` [PATCH net] bpf: test_run: fix WARNING in format_decode Yonghong Song
2023-11-27 14:10 ` Daniel Borkmann
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