[syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    48a97ffc6c82 bpf: Consistently use bpf_rcu_lock_held() eve..
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=144d0734580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16f7e5e2580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11ecec58580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/87ffd600eff3/disk-48a97ffc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aa84f0e32430/vmlinux-48a97ffc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/16498048e16c/bzImage-48a97ffc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com

skbuff: skb_over_panic: text:ffffffff8a1fdd63 len:392 put:16 head:ffff888073664d00 data:ffff888073664d00 tail:0x188 end:0x180 dev:<NULL>
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:212!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 6012 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:212
Code: c7 60 10 6e 8c 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 55 41 57 41 56 e8 6e 54 f5 ff 48 83 c4 20 90 <0f> 0b cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003d5eb68 EFLAGS: 00010282
RAX: 0000000000000088 RBX: dffffc0000000000 RCX: bc84b821dc35fd00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000180 R08: ffffc90003d5e867 R09: 1ffff920007abd0c
R10: dffffc0000000000 R11: fffff520007abd0d R12: ffff8880720b7b50
R13: ffff888073664d00 R14: ffff888073664d00 R15: 0000000000000188
FS:  000055555b9e7500(0000) GS:ffff888125e0c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555b9e7808 CR3: 000000007ead6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 skb_over_panic net/core/skbuff.c:217 [inline]
 skb_put+0x159/0x210 net/core/skbuff.c:2583
 skb_put_zero include/linux/skbuff.h:2788 [inline]
 set_ipsecrequest+0x73/0x680 net/key/af_key.c:3532
 pfkey_send_migrate+0x11f2/0x1de0 net/key/af_key.c:3636
 km_migrate+0x155/0x260 net/xfrm/xfrm_state.c:2838
 xfrm_migrate+0x2020/0x2330 net/xfrm/xfrm_policy.c:4698
 xfrm_do_migrate+0x796/0x900 net/xfrm/xfrm_user.c:3144
 xfrm_user_rcv_msg+0x7a3/0xab0 net/xfrm/xfrm_user.c:3501
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3523
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x830 net/socket.c:2630
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5fcd58eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe59dd1ab8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5fcd7e5fa0 RCX: 00007f5fcd58eec9
RDX: 0000000000000000 RSI: 0000200000000380 RDI: 0000000000000004
RBP: 00007f5fcd611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5fcd7e5fa0 R14: 00007f5fcd7e5fa0 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:212
Code: c7 60 10 6e 8c 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 55 41 57 41 56 e8 6e 54 f5 ff 48 83 c4 20 90 <0f> 0b cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003d5eb68 EFLAGS: 00010282
RAX: 0000000000000088 RBX: dffffc0000000000 RCX: bc84b821dc35fd00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000180 R08: ffffc90003d5e867 R09: 1ffff920007abd0c
R10: dffffc0000000000 R11: fffff520007abd0d R12: ffff8880720b7b50
R13: ffff888073664d00 R14: ffff888073664d00 R15: 0000000000000188
FS:  000055555b9e7500(0000) GS:ffff888125e0c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555b9e7808 CR3: 000000007ead6000 CR4: 00000000003526f0


---
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 syzkaller@googlegroups.com.

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

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

syzbot has bisected this issue to:

commit 14ad6ed30a10afbe91b0749d6378285f4225d482
Author: Paolo Abeni <pabeni@redhat.com>
Date:   Tue Feb 18 18:29:39 2025 +0000

    net: allow small head cache usage with large MAX_SKB_FRAGS values

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=177a35e2580000
start commit:   48a97ffc6c82 bpf: Consistently use bpf_rcu_lock_held() eve..
git tree:       bpf-next
final oops:     https://syzkaller.appspot.com/x/report.txt?x=14fa35e2580000
console output: https://syzkaller.appspot.com/x/log.txt?x=10fa35e2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16f7e5e2580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11ecec58580000

Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
Fixes: 14ad6ed30a10 ("net: allow small head cache usage with large MAX_SKB_FRAGS values")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[shaurya]

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


 From 123c5ac9ba261681b58a6217409c94722fde4249 Mon Sep 17 00:00:00 2001
From: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
Date: Sun, 19 Oct 2025 23:18:30 +0530
Subject: [PATCH] net: key: Validate address family in set_ipsecrequest()

syzbot reported a kernel BUG in set_ipsecrequest() due to an
skb_over_panic when processing XFRM_MSG_MIGRATE messages.

The root cause is that set_ipsecrequest() does not validate the
address family parameter before using it to calculate buffer sizes.
When an unsupported family value (such as 0) is passed,
pfkey_sockaddr_len() returns 0, leading to incorrect size calculations.

In pfkey_send_migrate(), the buffer size is calculated based on
pfkey_sockaddr_pair_size(), which uses pfkey_sockaddr_len(). When
family=0, this returns 0, so only sizeof(struct sadb_x_ipsecrequest)
(16 bytes) is allocated per entry. However, set_ipsecrequest() is
called multiple times in a loop (once for old_family, once for
new_family, for each migration bundle), repeatedly calling skb_put_zero()
with 16 bytes each time.

This causes the tail pointer to exceed the end pointer of the skb,
triggering skb_over_panic:
   tail: 0x188 (392 bytes)
   end:  0x180 (384 bytes)

Fix this by validating that pfkey_sockaddr_len() returns a non-zero
value before proceeding with buffer operations. This ensures proper
size calculations and prevents buffer overflow. Checking socklen
instead of just family==0 provides comprehensive validation for all
unsupported address families.

Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
Fixes: 08de61beab8a ("[PFKEYV2]: Extension for dynamic update of 
endpoint address(es)")

Signed-off-by: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
---
  net/key/af_key.c | 4 ++++
  1 file changed, 4 insertions(+)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2ebde0352245..713344c594d4 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3526,6 +3526,10 @@ static int set_ipsecrequest(struct sk_buff *skb,
      int socklen = pfkey_sockaddr_len(family);
      int size_req;

+    /* Reject invalid/unsupported address families */
+    if (!socklen)
+        return -EINVAL;
+
      size_req = sizeof(struct sadb_x_ipsecrequest) +
             pfkey_sockaddr_pair_size(family);

-- 
2.34.1

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

Hello,

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

failed to apply patch:
checking file net/key/af_key.c
patch: **** unexpected end of file in patch



Tested on:

commit:         d9043c79 Merge tag 'sched_urgent_for_v6.18_rc2' of git..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17653a14580000

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

Hello,

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

failed to apply patch:
checking file net/key/af_key.c
patch: **** unexpected end of file in patch



Tested on:

commit:         d9043c79 Merge tag 'sched_urgent_for_v6.18_rc2' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16621492580000

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

Hello,

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

failed to apply patch:
checking file net/key/af_key.c
patch: **** unexpected end of file in patch



Tested on:

commit:         d9043c79 Merge tag 'sched_urgent_for_v6.18_rc2' of git..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=10e21492580000

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

Hello,

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

failed to apply patch:
checking file net/key/af_key.c
patch: **** unexpected end of file in patch



Tested on:

commit:         7361c864 selftests/bpf: Fix list_del() in arena list
git tree:       bpf-next
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11031492580000

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[1599101385]

#syz test:
From 2edfc8833e43cdf5ccda8bd5be3da5d1bbdc69c6 Mon Sep 17 00:00:00 2001
From: clingfei <1599101385@qq.com>
Date: Mon, 20 Oct 2025 13:40:35 +0800
Subject: [PATCH] fix integer overflow in set_ipsecrequest
The mp->new_family and mp->old_family is u16, while set_ipsecrequest receives family as uint8_t, 
causing a integer overflow and the later size_req calculation error, which ultimately triggered a 
kernel bug in skb_put.

Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4

---
 net/key/af_key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2ebde0352245..08f4cde01994 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3518,7 +3518,7 @@ static int set_sadb_kmaddress(struct sk_buff *skb, const struct xfrm_kmaddress *

 static int set_ipsecrequest(struct sk_buff *skb,
                            uint8_t proto, uint8_t mode, int level,
-                           uint32_t reqid, uint8_t family,
+                           uint32_t reqid, uint16_t family,
                            const xfrm_address_t *src, const xfrm_address_t *dst)
 {
        struct sadb_x_ipsecrequest *rq;
--
2.34.1

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

> #syz test:

want either no args or 2 args (repo, branch), got 7

> From 2edfc8833e43cdf5ccda8bd5be3da5d1bbdc69c6 Mon Sep 17 00:00:00 2001
> From: clingfei <1599101385@qq.com>
> Date: Mon, 20 Oct 2025 13:40:35 +0800
> Subject: [PATCH] fix integer overflow in set_ipsecrequest
> The mp->new_family and mp->old_family is u16, while set_ipsecrequest receives family as uint8_t, 
> causing a integer overflow and the later size_req calculation error, which ultimately triggered a 
> kernel bug in skb_put.
>
> Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
>
> ---
>  net/key/af_key.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/key/af_key.c b/net/key/af_key.c
> index 2ebde0352245..08f4cde01994 100644
> --- a/net/key/af_key.c
> +++ b/net/key/af_key.c
> @@ -3518,7 +3518,7 @@ static int set_sadb_kmaddress(struct sk_buff *skb, const struct xfrm_kmaddress *
>
>  static int set_ipsecrequest(struct sk_buff *skb,
>                             uint8_t proto, uint8_t mode, int level,
> -                           uint32_t reqid, uint8_t family,
> +                           uint32_t reqid, uint16_t family,
>                             const xfrm_address_t *src, const xfrm_address_t *dst)
>  {
>         struct sadb_x_ipsecrequest *rq;
> --
> 2.34.1

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[1599101385]

#syz test

From 2edfc8833e43cdf5ccda8bd5be3da5d1bbdc69c6 Mon Sep 17 00:00:00 2001
From: clingfei <1599101385@qq.com>
Date: Mon, 20 Oct 2025 13:40:35 +0800
Subject: [PATCH] fix integer overflow in set_ipsecrequest
The mp->new_family and mp->old_family is u16, while set_ipsecrequest receives family as uint8_t, 
causing a integer overflow and the later size_req calculation error, which ultimately triggered a 
kernel bug in skb_put.

Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4

---
 net/key/af_key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 2ebde0352245..08f4cde01994 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3518,7 +3518,7 @@ static int set_sadb_kmaddress(struct sk_buff *skb, const struct xfrm_kmaddress *

 static int set_ipsecrequest(struct sk_buff *skb,
                            uint8_t proto, uint8_t mode, int level,
-                           uint32_t reqid, uint8_t family,
+                           uint32_t reqid, uint16_t family,
                            const xfrm_address_t *src, const xfrm_address_t *dst)
 {
        struct sadb_x_ipsecrequest *rq;
--
2.34.1

Re: [syzbot] [net?] kernel BUG in set_ipsecrequest

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com
Tested-by: syzbot+be97dd4da14ae88b6ba4@syzkaller.appspotmail.com

Tested on:

commit:         b54a8e13 Merge branch 'bpf-indirect-jumps'
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10dae114580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e46b8a1c645465a9
dashboard link: https://syzkaller.appspot.com/bug?extid=be97dd4da14ae88b6ba4
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=106ae114580000

Note: testing is done by a robot and is best-effort only.