2024-01-11 20:27:42

by syzbot

[permalink] [raw]
Subject: [syzbot] [net?] KMSAN: uninit-value in validate_xmit_skb

Hello,

syzbot found the following issue on:

HEAD commit: fbafc3e621c3 Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1135ab95e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=7f4d0ea3df4d4fa9a65f
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=15e15379e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=170f6981e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1520f7b6daa4/disk-fbafc3e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8b490af009d5/vmlinux-fbafc3e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/202ca200f4a4/bzImage-fbafc3e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

=====================================================
BUG: KMSAN: uninit-value in skb_gso_segment include/net/gso.h:83 [inline]
BUG: KMSAN: uninit-value in validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
skb_gso_segment include/net/gso.h:83 [inline]
validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
__dev_queue_xmit+0x1eac/0x5130 net/core/dev.c:4341
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3087 [inline]
packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline]
kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
__alloc_skb+0x318/0x740 net/core/skbuff.c:651
alloc_skb include/linux/skbuff.h:1286 [inline]
alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334
sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2780
packet_alloc_skb net/packet/af_packet.c:2936 [inline]
packet_snd net/packet/af_packet.c:3030 [inline]
packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline]
__do_sys_sendmsg net/socket.c:2676 [inline]
__se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 0 PID: 5025 Comm: syz-executor279 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup


2024-01-11 20:32:54

by Eric Dumazet

[permalink] [raw]
Subject: Re: [syzbot] [net?] KMSAN: uninit-value in validate_xmit_skb

On Thu, Jan 11, 2024 at 9:27 PM syzbot
<[email protected]> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: fbafc3e621c3 Merge tag 'for_linus' of git://git.kernel.org..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1135ab95e80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
> dashboard link: https://syzkaller.appspot.com/bug?extid=7f4d0ea3df4d4fa9a65f
> 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=15e15379e80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=170f6981e80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/1520f7b6daa4/disk-fbafc3e6.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/8b490af009d5/vmlinux-fbafc3e6.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/202ca200f4a4/bzImage-fbafc3e6.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> =====================================================
> BUG: KMSAN: uninit-value in skb_gso_segment include/net/gso.h:83 [inline]
> BUG: KMSAN: uninit-value in validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
> skb_gso_segment include/net/gso.h:83 [inline]
> validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
> __dev_queue_xmit+0x1eac/0x5130 net/core/dev.c:4341
> dev_queue_xmit include/linux/netdevice.h:3134 [inline]
> packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
> packet_snd net/packet/af_packet.c:3087 [inline]
> packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> Uninit was created at:
> slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
> slab_alloc_node mm/slub.c:3478 [inline]
> kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523
> kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
> __alloc_skb+0x318/0x740 net/core/skbuff.c:651
> alloc_skb include/linux/skbuff.h:1286 [inline]
> alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334
> sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2780
> packet_alloc_skb net/packet/af_packet.c:2936 [inline]
> packet_snd net/packet/af_packet.c:3030 [inline]
> packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119
> sock_sendmsg_nosec net/socket.c:730 [inline]
> __sock_sendmsg net/socket.c:745 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> __sys_sendmsg net/socket.c:2667 [inline]
> __do_sys_sendmsg net/socket.c:2676 [inline]
> __se_sys_sendmsg net/socket.c:2674 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>
> CPU: 0 PID: 5025 Comm: syz-executor279 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
> =====================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at [email protected].
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

```
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 27cc1d4643219a44c01a2404124cd45ef46f7f3d..4dfa9b69ca8d95d43e44831bc166eadbe5715d3c
100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -3,6 +3,8 @@
#define _LINUX_VIRTIO_NET_H

#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
#include <linux/udp.h>
#include <uapi/linux/tcp.h>
#include <uapi/linux/virtio_net.h>
@@ -49,6 +51,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
const struct virtio_net_hdr *hdr,
bool little_endian)
{
+ unsigned int nh_min_len = sizeof(struct iphdr);
unsigned int gso_type = 0;
unsigned int thlen = 0;
unsigned int p_off = 0;
@@ -65,6 +68,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
gso_type = SKB_GSO_TCPV6;
ip_proto = IPPROTO_TCP;
thlen = sizeof(struct tcphdr);
+ nh_min_len = sizeof(struct ipv6hdr);
break;
case VIRTIO_NET_HDR_GSO_UDP:
gso_type = SKB_GSO_UDP;
@@ -100,7 +104,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
if (!skb_partial_csum_set(skb, start, off))
return -EINVAL;

- p_off = skb_transport_offset(skb) + thlen;
+ nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb));
+ p_off = nh_min_len + thlen;
if (!pskb_may_pull(skb, p_off))
return -EINVAL;
} else {
@@ -140,7 +145,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,

skb_set_transport_header(skb, keys.control.thoff);
} else if (gso_type) {
- p_off = thlen;
+ p_off = nh_min_len + thlen;
if (!pskb_may_pull(skb, p_off))
return -EINVAL;
}
```

2024-01-11 20:33:00

by syzbot

[permalink] [raw]
Subject: Re: [syzbot] [net?] KMSAN: uninit-value in validate_xmit_skb

> On Thu, Jan 11, 2024 at 9:27 PM syzbot
> <[email protected]> wrote:
>>
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: fbafc3e621c3 Merge tag 'for_linus' of git://git.kernel.org..
>> git tree: upstream
>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1135ab95e80000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
>> dashboard link: https://syzkaller.appspot.com/bug?extid=7f4d0ea3df4d4fa9a65f
>> 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=15e15379e80000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=170f6981e80000
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/1520f7b6daa4/disk-fbafc3e6.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/8b490af009d5/vmlinux-fbafc3e6.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/202ca200f4a4/bzImage-fbafc3e6.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: [email protected]
>>
>> =====================================================
>> BUG: KMSAN: uninit-value in skb_gso_segment include/net/gso.h:83 [inline]
>> BUG: KMSAN: uninit-value in validate_xmit_skb+0x10f2/0x1930 net/core/devc:3629
>> skb_gso_segment include/net/gso.h:83 [inline]
>> validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
>> __dev_queue_xmit+0x1eac/0x5130 net/core/dev.c:4341
>> dev_queue_xmit include/linux/netdevice.h:3134 [inline]
>> packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
>> packet_snd net/packet/af_packet.c:3087 [inline]
>> packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
>> sock_sendmsg_nosec net/socket.c:730 [inline]
>> __sock_sendmsg net/socket.c:745 [inline]
>> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
>> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
>> __sys_sendmsg net/socket.c:2667 [inline]
>> __do_sys_sendmsg net/socket.c:2676 [inline]
>> __se_sys_sendmsg net/socket.c:2674 [inline]
>> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>>
>> Uninit was created at:
>> slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
>> slab_alloc_node mm/slub.c:3478 [inline]
>> kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523
>> kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
>> __alloc_skb+0x318/0x740 net/core/skbuff.c:651
>> alloc_skb include/linux/skbuff.h:1286 [inline]
>> alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334
>> sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2780
>> packet_alloc_skb net/packet/af_packet.c:2936 [inline]
>> packet_snd net/packet/af_packet.c:3030 [inline]
>> packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119
>> sock_sendmsg_nosec net/socket.c:730 [inline]
>> __sock_sendmsg net/socket.c:745 [inline]
>> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
>> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
>> __sys_sendmsg net/socket.c:2667 [inline]
>> __do_sys_sendmsg net/socket.c:2676 [inline]
>> __se_sys_sendmsg net/socket.c:2674 [inline]
>> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x63/0x6b
>>
>> CPU: 0 PID: 5025 Comm: syz-executor279 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
>> =====================================================
>>
>>
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at [email protected].
>>
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>>
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>>
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
>>
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>>
>> If the report is a duplicate of another one, reply with:
>> #syz dup: exact-subject-of-another-report
>>
>> If you want to undo deduplication, reply with:
>> #syz undup
>
> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

want either no args or 2 args (repo, branch), got 1

> master
>
> ```
> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
> index 27cc1d4643219a44c01a2404124cd45ef46f7f3d..4dfa9b69ca8d95d43e44831bc166eadbe5715d3c
> 100644
> --- a/include/linux/virtio_net.h
> +++ b/include/linux/virtio_net.h
> @@ -3,6 +3,8 @@
> #define _LINUX_VIRTIO_NET_H
>
> #include <linux/if_vlan.h>
> +#include <linux/ip.h>
> +#include <linux/ipv6.h>
> #include <linux/udp.h>
> #include <uapi/linux/tcp.h>
> #include <uapi/linux/virtio_net.h>
> @@ -49,6 +51,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
> const struct virtio_net_hdr *hdr,
> bool little_endian)
> {
> + unsigned int nh_min_len = sizeof(struct iphdr);
> unsigned int gso_type = 0;
> unsigned int thlen = 0;
> unsigned int p_off = 0;
> @@ -65,6 +68,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
> gso_type = SKB_GSO_TCPV6;
> ip_proto = IPPROTO_TCP;
> thlen = sizeof(struct tcphdr);
> + nh_min_len = sizeof(struct ipv6hdr);
> break;
> case VIRTIO_NET_HDR_GSO_UDP:
> gso_type = SKB_GSO_UDP;
> @@ -100,7 +104,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
> if (!skb_partial_csum_set(skb, start, off))
> return -EINVAL;
>
> - p_off = skb_transport_offset(skb) + thlen;
> + nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb));
> + p_off = nh_min_len + thlen;
> if (!pskb_may_pull(skb, p_off))
> return -EINVAL;
> } else {
> @@ -140,7 +145,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
>
> skb_set_transport_header(skb, keys.control.thoff);
> } else if (gso_type) {
> - p_off = thlen;
> + p_off = nh_min_len + thlen;
> if (!pskb_may_pull(skb, p_off))
> return -EINVAL;
> }
> ```

2024-01-11 20:35:11

by syzbot

[permalink] [raw]
Subject: Re: [syzbot] Re: [syzbot] [net?] KMSAN: uninit-value in validate_xmit_skb

For archival purposes, forwarding an incoming command email to
[email protected], [email protected].

***

Subject: Re: [syzbot] [net?] KMSAN: uninit-value in validate_xmit_skb
Author: [email protected]

On Thu, Jan 11, 2024 at 9:32 PM syzbot
<[email protected]> wrote:
>
> > On Thu, Jan 11, 2024 at 9:27 PM syzbot
> > <[email protected]> wrote:
> >>
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit: fbafc3e621c3 Merge tag 'for_linus' of git://git.kernelorg..
> >> git tree: upstream
> >> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1135ab95e80000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=7f4d0ea3df4d4fa9a65f
> >> 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=15e15379e80000
> >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=170f6981e80000
> >>
> >> Downloadable assets:
> >> disk image: https://storage.googleapis.com/syzbot-assets/1520f7b6daa4/disk-fbafc3e6.raw.xz
> >> vmlinux: https://storage.googleapis.com/syzbot-assets/8b490af009d5/vmlinux-fbafc3e6.xz
> >> kernel image: https://storage.googleapis.com/syzbot-assets/202ca200f4a4/bzImage-fbafc3e6.xz
> >>
> >> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> Reported-by: [email protected]
> >>
> >> =====================================================
> >> BUG: KMSAN: uninit-value in skb_gso_segment include/net/gso.h:83 [inline]
> >> BUG: KMSAN: uninit-value in validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
> >> skb_gso_segment include/net/gso.h:83 [inline]
> >> validate_xmit_skb+0x10f2/0x1930 net/core/dev.c:3629
> >> __dev_queue_xmit+0x1eac/0x5130 net/core/dev.c:4341
> >> dev_queue_xmit include/linux/netdevice.h:3134 [inline]
> >> packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
> >> packet_snd net/packet/af_packet.c:3087 [inline]
> >> packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
> >> sock_sendmsg_nosec net/socket.c:730 [inline]
> >> __sock_sendmsg net/socket.c:745 [inline]
> >> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> >> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> >> __sys_sendmsg net/socket.c:2667 [inline]
> >> __do_sys_sendmsg net/socket.c:2676 [inline]
> >> __se_sys_sendmsg net/socket.c:2674 [inline]
> >> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> >> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> >> entry_SYSCALL_64_after_hwframe+0x63/0x6b
> >>
> >> Uninit was created at:
> >> slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
> >> slab_alloc_node mm/slub.c:3478 [inline]
> >> kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523
> >> kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
> >> __alloc_skb+0x318/0x740 net/core/skbuff.c:651
> >> alloc_skb include/linux/skbuff.h:1286 [inline]
> >> alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6334
> >> sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2780
> >> packet_alloc_skb net/packet/af_packet.c:2936 [inline]
> >> packet_snd net/packet/af_packet.c:3030 [inline]
> >> packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119
> >> sock_sendmsg_nosec net/socket.c:730 [inline]
> >> __sock_sendmsg net/socket.c:745 [inline]
> >> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
> >> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
> >> __sys_sendmsg net/socket.c:2667 [inline]
> >> __do_sys_sendmsg net/socket.c:2676 [inline]
> >> __se_sys_sendmsg net/socket.c:2674 [inline]
> >> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674
> >> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >> do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
> >> entry_SYSCALL_64_after_hwframe+0x63/0x6b
> >>
> >> CPU: 0 PID: 5025 Comm: syz-executor279 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
> >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
> >> =====================================================
> >>
> >>
> >> ---
> >> This report is generated by a bot. It may contain errors.
> >> See https://goo.gl/tpsmEJ for more information about syzbot.
> >> syzbot engineers can be reached at [email protected].
> >>
> >> syzbot will keep track of this issue. See:
> >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >>
> >> If the report is already addressed, let syzbot know by replying with:
> >> #syz fix: exact-commit-title
> >>
> >> If you want syzbot to run the reproducer, reply with:
> >> #syz test: git://repo/address.git branch-or-commit-hash
> >> If you attach or paste a git patch, syzbot will apply it before testing.
> >>
> >> If you want to overwrite report's subsystems, reply with:
> >> #syz set subsystems: new-subsystem
> >> (See the list of subsystem names on the web dashboard)
> >>
> >> If the report is a duplicate of another one, reply with:
> >> #syz dup: exact-subject-of-another-report
> >>
> >> If you want to undo deduplication, reply with:
> >> #syz undup
> >
> > #syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>
> want either no args or 2 args (repo, branch), got 1


#syz test

```
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 27cc1d4643219a44c01a2404124cd45ef46f7f3d..4dfa9b69ca8d95d43e44831bc166eadbe5715d3c
100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -3,6 +3,8 @@
#define _LINUX_VIRTIO_NET_H

#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
#include <linux/udp.h>
#include <uapi/linux/tcp.h>
#include <uapi/linux/virtio_net.h>
@@ -49,6 +51,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
const struct virtio_net_hdr *hdr,
bool little_endian)
{
+ unsigned int nh_min_len = sizeof(struct iphdr);
unsigned int gso_type = 0;
unsigned int thlen = 0;
unsigned int p_off = 0;
@@ -65,6 +68,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
gso_type = SKB_GSO_TCPV6;
ip_proto = IPPROTO_TCP;
thlen = sizeof(struct tcphdr);
+ nh_min_len = sizeof(struct ipv6hdr);
break;
case VIRTIO_NET_HDR_GSO_UDP:
gso_type = SKB_GSO_UDP;
@@ -100,7 +104,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
if (!skb_partial_csum_set(skb, start, off))
return -EINVAL;

- p_off = skb_transport_offset(skb) + thlen;
+ nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb));
+ p_off = nh_min_len + thlen;
if (!pskb_may_pull(skb, p_off))
return -EINVAL;
} else {
@@ -140,7 +145,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,

skb_set_transport_header(skb, keys.control.thoff);
} else if (gso_type) {
- p_off = thlen;
+ p_off = nh_min_len + thlen;
if (!pskb_may_pull(skb, p_off))
return -EINVAL;
}
```

2024-01-12 05:12:13

by syzbot

[permalink] [raw]
Subject: Re: [syzbot] [net?] KMSAN: uninit-value in validate_xmit_skb

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file include/linux/virtio_net.h
patch: **** unexpected end of file in patch



Tested on:

commit: 70d201a4 Merge tag 'f2fs-for-6.8-rc1' of git://git.ker..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=7f4d0ea3df4d4fa9a65f
compiler:
patch: https://syzkaller.appspot.com/x/patch.diff?x=11c430a5e80000