syzbot


KMSAN: uninit-value in slhc_remember

Status: fixed on 2024/11/12 23:31
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+2ada1bc857496353be5a@syzkaller.appspotmail.com
Fix commit: 7d3fce8cbe3a slip: make slhc_remember() more robust against malicious packets
First crash: 57d, last: 56d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH net] slip: make slhc_remember() more robust against malicious packets 2 (2) 2024/10/10 16:10
[syzbot] [net?] KMSAN: uninit-value in slhc_remember 0 (1) 2024/10/09 09:03

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in slhc_remember+0x2e8/0x7b0 drivers/net/slip/slhc.c:666
 slhc_remember+0x2e8/0x7b0 drivers/net/slip/slhc.c:666
 ppp_receive_nonmp_frame+0xe45/0x35e0 drivers/net/ppp/ppp_generic.c:2455
 ppp_receive_frame drivers/net/ppp/ppp_generic.c:2372 [inline]
 ppp_do_recv+0x65f/0x40d0 drivers/net/ppp/ppp_generic.c:2212
 ppp_input+0x7dc/0xe60 drivers/net/ppp/ppp_generic.c:2327
 pppoe_rcv_core+0x1d3/0x720 drivers/net/ppp/pppoe.c:379
 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1113
 __release_sock+0x1da/0x330 net/core/sock.c:3072
 release_sock+0x6b/0x250 net/core/sock.c:3626
 pppoe_sendmsg+0x2b8/0xb90 drivers/net/ppp/pppoe.c:903
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:744
 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656
 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742
 __do_sys_sendmmsg net/socket.c:2771 [inline]
 __se_sys_sendmmsg net/socket.c:2768 [inline]
 __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768
 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4091 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4186
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1322 [inline]
 sock_wmalloc+0xfe/0x1a0 net/core/sock.c:2732
 pppoe_sendmsg+0x3a7/0xb90 drivers/net/ppp/pppoe.c:867
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:744
 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656
 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742
 __do_sys_sendmmsg net/socket.c:2771 [inline]
 __se_sys_sendmmsg net/socket.c:2768 [inline]
 __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768
 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 11151 Comm: syz.3.1054 Not tainted 6.12.0-rc2-syzkaller-00050-g5b7c893ed5ed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/09 02:05 upstream 5b7c893ed5ed 402f1df0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in slhc_remember
2024/10/09 02:05 upstream 5b7c893ed5ed 402f1df0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in slhc_remember
2024/10/08 07:51 upstream 87d6aab2389e 402f1df0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in slhc_remember
2024/10/08 07:48 upstream 87d6aab2389e 402f1df0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in slhc_remember
* Struck through repros no longer work on HEAD.