Re: [syzbot] [io-uring?] UBSAN: array-index-out-of-bounds in io_setup_async_msg

[syzbot <syzbot+a4c6e5ef999b68b26ed1@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: array-index-out-of-bounds in io_setup_async_msg

================================================================================
UBSAN: array-index-out-of-bounds in io_uring/net.c:189:55
index 3779565697114 is out of range for type 'iovec [8]'
CPU: 1 PID: 5467 Comm: syz-executor.0 Not tainted 6.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x125/0x1b0 lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:217 [inline]
 __ubsan_handle_out_of_bounds+0x111/0x150 lib/ubsan.c:348
 io_setup_async_msg+0x2a0/0x2b0 io_uring/net.c:189
 io_recvmsg+0x169f/0x2170 io_uring/net.c:781
 io_issue_sqe+0x54a/0xd80 io_uring/io_uring.c:1878
 io_queue_sqe io_uring/io_uring.c:2063 [inline]
 io_submit_sqe io_uring/io_uring.c:2323 [inline]
 io_submit_sqes+0x96c/0x1ed0 io_uring/io_uring.c:2438
 __do_sys_io_uring_enter+0x14ea/0x2650 io_uring/io_uring.c:3647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9a8a27cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9a8af210c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007f9a8a39bf80 RCX: 00007f9a8a27cae9
RDX: 0000000000000000 RSI: 0000000000007689 RDI: 0000000000000003
RBP: 00007f9a8a2c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f9a8a39bf80 R15: 00007ffd083c1e58
 </TASK>
================================================================================


Tested on:

commit:         0bb80ecc Linux 6.6-rc1
git tree:       https://github.com/isilence/linux.git syz-test/netmsg-init-base
console output: https://syzkaller.appspot.com/x/log.txt?x=15ccbf30680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f4894cf58531f
dashboard link: https://syzkaller.appspot.com/bug?extid=a4c6e5ef999b68b26ed1
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.