2024-10-21 18:02:03
Linux
PUBLISHED
In the Linux kernel, the following vulnerability has been resolved:
ppp: do not assume bh is held in ppp_channel_bridge_input()
Networking receive path is usually handled from BH handler.
However, some protocols need to acquire the socket lock, and
packets might be stored in the socket backlog is the socket was
owned by a user process.
In this case, release_sock(), __release_sock(), and sk_backlog_rcv()
might call the sk->sk_backlog_rcv() handler in process context.
sybot caught ppp was not considering this case in
ppp_channel_bridge_input() :
WARNING: inconsistent lock state
6.11.0-rc7-syzkaller-g5f5673607153 #0 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
ksoftirqd/1/24 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]
ffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
{SOFTIRQ-ON-W} state was registered at:
lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]
ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
pppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379
sk_backlog_rcv include/net/sock.h:1111 [inline]
__release_sock+0x1a8/0x3d8 net/core/sock.c:3004
release_sock+0x68/0x1b8 net/core/sock.c:3558
pppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x374/0x4f4 net/socket.c:2204
__do_sys_sendto net/socket.c:2216 [inline]
__se_sys_sendto net/socket.c:2212 [inline]
__arm64_sys_sendto+0xd8/0xf8 net/socket.c:2212
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
irq event stamp: 282914
hardirqs last enabled at (282914): [