CVE-2024-46783

In the Linux kernel, the following vulnerability has been resolved:

tcp_bpf: fix return value of tcp_bpf_sendmsg()

When we cork messages in psock->cork, the last message triggers the

flushing will result in sending a sk_msg larger than the current

message size. In this case, in tcp_bpf_send_verdict(), 'copied' becomes

negative at least in the following case:

468 case __SK_DROP:

469 default:

470 sk_msg_free_partial(sk, msg, tosend);

471 sk_msg_apply_bytes(psock, tosend);

472 *copied -= (tosend + delta); // <==== HERE

473 return -EACCES;

Therefore, it could lead to the following BUG with a proper value of

'copied' (thanks to syzbot). We should not use negative 'copied' as a

return value here.

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kernel BUG at net/socket.c:733!

Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP

Modules linked in:

CPU: 0 UID: 0 PID: 3265 Comm: syz-executor510 Not tainted 6.11.0-rc3-syzkaller-00060-gd07b43284ab3 #0

Hardware name: linux,dummy-virt (DT)

pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)

pc : sock_sendmsg_nosec net/socket.c:733 [inline]

pc : sock_sendmsg_nosec net/socket.c:728 [inline]

pc : __sock_sendmsg+0x5c/0x60 net/socket.c:745

lr : sock_sendmsg_nosec net/socket.c:730 [inline]

lr : __sock_sendmsg+0x54/0x60 net/socket.c:745

sp : ffff800088ea3b30

x29: ffff800088ea3b30 x28: fbf00000062bc900 x27: 0000000000000000

x26: ffff800088ea3bc0 x25: ffff800088ea3bc0 x24: 0000000000000000

x23: f9f00000048dc000 x22: 0000000000000000 x21: ffff800088ea3d90

x20: f9f00000048dc000 x19: ffff800088ea3d90 x18: 0000000000000001

x17: 0000000000000000 x16: 0000000000000000 x15: 000000002002ffaf

x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000

x11: 0000000000000000 x10: ffff8000815849c0 x9 : ffff8000815b49c0

x8 : 0000000000000000 x7 : 000000000000003f x6 : 0000000000000000

x5 : 00000000000007e0 x4 : fff07ffffd239000 x3 : fbf00000062bc900

x2 : 0000000000000000 x1 : 0000000000000000 x0 : 00000000fffffdef

Call trace:

sock_sendmsg_nosec net/socket.c:733 [inline]

__sock_sendmsg+0x5c/0x60 net/socket.c:745

____sys_sendmsg+0x274/0x2ac net/socket.c:2597

___sys_sendmsg+0xac/0x100 net/socket.c:2651

__sys_sendmsg+0x84/0xe0 net/socket.c:2680

__do_sys_sendmsg net/socket.c:2689 [inline]

__se_sys_sendmsg net/socket.c:2687 [inline]

__arm64_sys_sendmsg+0x24/0x30 net/socket.c:2687

__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]

invoke_syscall+0x48/0x110 arch/arm64/kernel/syscall.c:49

el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:132

do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:151

el0_svc+0x34/0xec arch/arm64/kernel/entry-common.c:712

el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:730

el0t_64_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:598

Code: f9404463 d63f0060 3108441f 54fffe81 (d4210000)

---[ end trace 0000000000000000 ]---