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BUG: bad usercopy in skb_copy_datagram_from_iter

Status: closed as invalid on 2024/11/27 19:42
Subsystems: hardening mm
[Documentation on labels]
First crash: 72d, last: 72d

Sample crash report:
usercopy: Kernel memory overwrite attempt detected to SLUB object 'skbuff_small_head' (offset 644, size 14)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 UID: 0 PID: 6500 Comm: syz.2.284 Not tainted 6.12.0-rc3-syzkaller-00013-geca631b8fe80 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:usercopy_abort+0x84/0x90 mm/usercopy.c:102
Code: 49 89 ce 48 c7 c3 c0 8d 18 8c 48 0f 44 de 48 c7 c7 60 8c 18 8c 4c 89 de 48 89 c1 41 52 41 56 53 e8 91 03 af 09 48 83 c4 18 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90002edf808 EFLAGS: 00010282
RAX: 000000000000006c RBX: ffffffff8c188dc0 RCX: afce8a751f681300
RDX: ffffc90005021000 RSI: 0000000000003492 RDI: 0000000000003493
RBP: 0000000000000284 R08: ffffffff8174af9c R09: fffffbfff1cf9fd8
R10: dffffc0000000000 R11: fffffbfff1cf9fd8 R12: dffffc0000000000
R13: 000000000000000e R14: 0000000000000284 R15: 000000000000000e
FS:  00007fd7ff73e6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7ff73ed58 CR3: 0000000028738000 CR4: 00000000003526f0
DR0: 0000000000000005 DR1: 000000000000000a DR2: 0000000000000002
DR3: 0000000000000010 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __check_heap_object+0xb1/0x100 mm/slub.c:5651
 check_heap_object mm/usercopy.c:196 [inline]
 __check_object_size+0x1df/0x900 mm/usercopy.c:251
 check_object_size include/linux/thread_info.h:215 [inline]
 check_copy_size include/linux/thread_info.h:251 [inline]
 copy_from_iter include/linux/uio.h:218 [inline]
 skb_copy_datagram_from_iter+0xe2/0x6a0 net/core/datagram.c:564
 packet_snd net/packet/af_packet.c:3108 [inline]
 packet_sendmsg+0x435c/0x6860 net/packet/af_packet.c:3177
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:744
 __sys_sendto+0x39b/0x4f0 net/socket.c:2214
 __do_sys_sendto net/socket.c:2226 [inline]
 __se_sys_sendto net/socket.c:2222 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2222
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd7fe97dff9
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:00007fd7ff73e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fd7feb36058 RCX: 00007fd7fe97dff9
RDX: 000000000000000e RSI: 0000000020000140 RDI: 0000000000000005
RBP: 00007fd7fe9f0296 R08: 00000000200000c0 R09: 0000000000000014
R10: 0300000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fd7feb36058 R15: 00007ffec18f5cb8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:usercopy_abort+0x84/0x90 mm/usercopy.c:102
Code: 49 89 ce 48 c7 c3 c0 8d 18 8c 48 0f 44 de 48 c7 c7 60 8c 18 8c 4c 89 de 48 89 c1 41 52 41 56 53 e8 91 03 af 09 48 83 c4 18 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90002edf808 EFLAGS: 00010282
RAX: 000000000000006c RBX: ffffffff8c188dc0 RCX: afce8a751f681300
RDX: ffffc90005021000 RSI: 0000000000003492 RDI: 0000000000003493
RBP: 0000000000000284 R08: ffffffff8174af9c R09: fffffbfff1cf9fd8
R10: dffffc0000000000 R11: fffffbfff1cf9fd8 R12: dffffc0000000000
R13: 000000000000000e R14: 0000000000000284 R15: 000000000000000e
FS:  00007fd7ff73e6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555578cfa5c8 CR3: 0000000028738000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/15 10:03 upstream eca631b8fe80 14943bb8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root BUG: bad usercopy in skb_copy_datagram_from_iter
* Struck through repros no longer work on HEAD.