[syzbot] [tipc?] KMSAN: uninit-value in __tipc_nl_bearer_enable (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a0fc73da97e Merge tag 's390-6.6-2' of git://git.kernel.or..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15cc921c680000
kernel config: https://syzkaller.appspot.com/x/.config?x=a2fd75f3f45dd99
dashboard link: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1737422c680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13c74c94680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/28d14dd1284c/disk-4a0fc73d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a5ca8dd87357/vmlinux-4a0fc73d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c7dda831a503/bzImage-4a0fc73d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9425c4...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
strscpy+0xc4/0x160
bearer_name_validate net/tipc/bearer.c:147 [inline]
tipc_enable_bearer net/tipc/bearer.c:259 [inline]
__tipc_nl_bearer_enable+0x634/0x2220 net/tipc/bearer.c:1043
tipc_nl_bearer_enable+0x3c/0x70 net/tipc/bearer.c:1052
genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066
netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075
netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910
sock_sendmsg_nosec net/socket.c:730 [inline]
sock_sendmsg net/socket.c:753 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
__sys_sendmsg net/socket.c:2623 [inline]
__do_sys_sendmsg net/socket.c:2632 [inline]
__se_sys_sendmsg net/socket.c:2630 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
slab_alloc_node mm/slub.c:3478 [inline]
kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
kmalloc_reserve+0x148/0x470 net/core/skbuff.c:559
__alloc_skb+0x318/0x740 net/core/skbuff.c:644
alloc_skb include/linux/skbuff.h:1286 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline]
netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885
sock_sendmsg_nosec net/socket.c:730 [inline]
sock_sendmsg net/socket.c:753 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
__sys_sendmsg net/socket.c:2623 [inline]
__do_sys_sendmsg net/socket.c:2632 [inline]
__se_sys_sendmsg net/socket.c:2630 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

CPU: 1 PID: 4993 Comm: syz-executor386 Not tainted 6.5.0-syzkaller-12145-g4a0fc73da97e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
=====================================================


---
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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, 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 bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

please test uninit in tipc_enable_bearer

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 4a0fc73da97e

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 2cde375477e3..b4629ff03e67 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -256,7 +256,7 @@ static int tipc_enable_bearer(struct net *net, const char *name,
char *errstr = "";
u32 i;

- if (!bearer_name_validate(name, &b_names)) {
+ if (IS_ERR_OR_NULL(name) || !bearer_name_validate(name, &b_names)) {
NL_SET_ERR_MSG(extack, "Illegal name");
return res;
}

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in __tipc_nl_bearer_enable

=====================================================
BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
strscpy+0xc4/0x160
bearer_name_validate net/tipc/bearer.c:147 [inline]
tipc_enable_bearer net/tipc/bearer.c:259 [inline]

__tipc_nl_bearer_enable+0x6bf/0x22c0 net/tipc/bearer.c:1043

CPU: 0 PID: 5453 Comm: syz-executor.0 Not tainted 6.5.0-syzkaller-12145-g4a0fc73da97e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
=====================================================


Tested on:

commit: 4a0fc73d Merge tag 's390-6.6-2' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1702b4b6680000

kernel config: https://syzkaller.appspot.com/x/.config?x=a2fd75f3f45dd99
dashboard link: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=14bd98fa680000

[ead...@sina.com]

From: Edward AD <ead...@sina.com>

please test uninit in tipc_enable_bearer

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 4a0fc73da97e

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c

index 2cde375477e3..de21601162c0 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -256,7 +256,8 @@ static int tipc_enable_bearer(struct net *net, const char *name,

char *errstr = "";
u32 i;

- if (!bearer_name_validate(name, &b_names)) {

+ if (IS_ERR_OR_NULL(name) || strlen(name) == 0 ||
+ !bearer_name_validate(name, &b_names)) {

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in __tipc_nl_bearer_enable

=====================================================
BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
strscpy+0xc4/0x160
bearer_name_validate net/tipc/bearer.c:147 [inline]

tipc_enable_bearer net/tipc/bearer.c:260 [inline]
__tipc_nl_bearer_enable+0x6df/0x2330 net/tipc/bearer.c:1044
tipc_nl_bearer_enable+0x3c/0x70 net/tipc/bearer.c:1053

CPU: 1 PID: 5445 Comm: syz-executor.0 Not tainted 6.5.0-syzkaller-12145-g4a0fc73da97e-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
=====================================================


Tested on:

commit: 4a0fc73d Merge tag 's390-6.6-2' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=12644cfa680000

kernel config: https://syzkaller.appspot.com/x/.config?x=a2fd75f3f45dd99
dashboard link: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17e4675c680000