[syzbot] KMSAN: uninit-value in ethnl_set_linkmodes (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4b28366af7d9 x86: kmsan: enable KMSAN builds for x86
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=169d3317f00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d14e10a167d1c585
dashboard link: https://syzkaller.appspot.com/bug?extid=ef6edd9f1baaa54d6235
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ef6edd...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in ethnl_update_u32 net/ethtool/netlink.h:81 [inline]
BUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:295 [inline]
BUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x1469/0x2270 net/ethtool/linkmodes.c:344
ethnl_update_u32 net/ethtool/netlink.h:81 [inline]
ethnl_update_linkmodes net/ethtool/linkmodes.c:295 [inline]
ethnl_set_linkmodes+0x1469/0x2270 net/ethtool/linkmodes.c:344
genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0x103f/0x1260 net/netlink/genetlink.c:792
netlink_rcv_skb+0x3a5/0x6c0 net/netlink/af_netlink.c:2501
genl_rcv+0x3c/0x50 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0xf3b/0x1270 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x1288/0x1440 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0xabc/0xe90 net/socket.c:2492
___sys_sendmsg+0x2a5/0x350 net/socket.c:2546
__sys_sendmsg net/socket.c:2575 [inline]
__do_sys_sendmsg net/socket.c:2584 [inline]
__se_sys_sendmsg net/socket.c:2582 [inline]
__x64_sys_sendmsg+0x367/0x540 net/socket.c:2582
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Uninit was stored to memory at:
tun_get_link_ksettings+0x3e/0x60 drivers/net/tun.c:3515
__ethtool_get_link_ksettings+0x181/0x270 net/ethtool/ioctl.c:461
ethnl_set_linkmodes+0x57c/0x2270 net/ethtool/linkmodes.c:338
genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0x103f/0x1260 net/netlink/genetlink.c:792
netlink_rcv_skb+0x3a5/0x6c0 net/netlink/af_netlink.c:2501
genl_rcv+0x3c/0x50 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0xf3b/0x1270 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x1288/0x1440 net/netlink/af_netlink.c:1921
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0xabc/0xe90 net/socket.c:2492
___sys_sendmsg+0x2a5/0x350 net/socket.c:2546
__sys_sendmsg net/socket.c:2575 [inline]
__do_sys_sendmsg net/socket.c:2584 [inline]
__se_sys_sendmsg net/socket.c:2582 [inline]
__x64_sys_sendmsg+0x367/0x540 net/socket.c:2582
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Uninit was stored to memory at:
tun_set_link_ksettings+0x3e/0x60 drivers/net/tun.c:3524
ethtool_set_link_ksettings+0x607/0x6a0 net/ethtool/ioctl.c:628
__dev_ethtool net/ethtool/ioctl.c:2997 [inline]
dev_ethtool+0x1862/0x2600 net/ethtool/ioctl.c:3051
dev_ioctl+0x369/0x1020 net/core/dev_ioctl.c:524
sock_do_ioctl+0x295/0x540 net/socket.c:1183
sock_ioctl+0x556/0xc90 net/socket.c:1286
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0x222/0x400 fs/ioctl.c:856
__x64_sys_ioctl+0x92/0xd0 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Local variable link_ksettings created at:
ethtool_set_link_ksettings+0x54/0x6a0 net/ethtool/ioctl.c:596
__dev_ethtool net/ethtool/ioctl.c:2997 [inline]
dev_ethtool+0x1862/0x2600 net/ethtool/ioctl.c:3051

CPU: 0 PID: 20786 Comm: syz-executor.2 Not tainted 5.19.0-rc3-syzkaller-30868-g4b28366af7d9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 81af97bdef5e printk: Export console trace point for kcsan/..

git tree: https://github.com/google/kmsan.git master

console+strace: https://syzkaller.appspot.com/x/log.txt?x=10d4b844280000
kernel config: https://syzkaller.appspot.com/x/.config?x=ee7e125556b25104
dashboard link: https://syzkaller.appspot.com/bug?extid=ef6edd9f1baaa54d6235
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1543bf0c280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158f4664280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/00b0f311889c/disk-81af97bd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a3291e9cce5a/vmlinux-81af97bd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/09b5e66af8b4/bzImage-81af97bd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ef6edd...@syzkaller.appspotmail.com

=====================================================

BUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
BUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]
ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
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 stored to memory at:

tun_get_link_ksettings+0x37/0x60 drivers/net/tun.c:3544
__ethtool_get_link_ksettings+0x17b/0x260 net/ethtool/ioctl.c:441
ethnl_set_linkmodes+0xee/0x19d0 net/ethtool/linkmodes.c:327
ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640
genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065
netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0xa24/0xe40 net/socket.c:2501
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555
__sys_sendmsg net/socket.c:2584 [inline]
__do_sys_sendmsg net/socket.c:2593 [inline]
__se_sys_sendmsg net/socket.c:2591 [inline]
__x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591
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 stored to memory at:

tun_set_link_ksettings+0x37/0x60 drivers/net/tun.c:3553
ethtool_set_link_ksettings+0x600/0x690 net/ethtool/ioctl.c:609
__dev_ethtool net/ethtool/ioctl.c:3024 [inline]
dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078
dev_ioctl+0xb07/0x1270 net/core/dev_ioctl.c:524
sock_do_ioctl+0x295/0x540 net/socket.c:1213
sock_ioctl+0x729/0xd90 net/socket.c:1316

vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0x222/0x400 fs/ioctl.c:856

__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:856
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

Local variable link_ksettings created at:

ethtool_set_link_ksettings+0x54/0x690 net/ethtool/ioctl.c:577
__dev_ethtool net/ethtool/ioctl.c:3024 [inline]
dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078

CPU: 1 PID: 4952 Comm: syz-executor743 Not tainted 6.3.0-syzkaller-g81af97bdef5e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
=====================================================


---
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.

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+ef6edd...@syzkaller.appspotmail.com

Tested on:

commit: 66863178 net: dsa: mv88e6xxx: add mv88e6321 rsvd2cpu
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1106c0dfc80000
kernel config: https://syzkaller.appspot.com/x/.config?x=6bb01a8d28d10570

dashboard link: https://syzkaller.appspot.com/bug?extid=ef6edd9f1baaa54d6235
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=138de410280000

Note: testing is done by a robot and is best-effort only.

[Ido Schimmel]

The problem seems to be that 'struct ethtool_link_ksettings::lanes' is
not initialized in load_link_ksettings_from_user(). We can zero it
there, but a more robust approach would be to initialize the structure
in ethtool_set_link_ksettings().

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git main