In the Linux kernel, the following vulnerability has been resolved:
netrom: fix possible dead-lock in nr_rt_ioctl()
syzbot loves netrom, and found a possible deadlock in nr_rt_ioctl [1]
Make sure we always acquire nr_node_list_lock before nr_node_lock(nr_node)
syz-executor350/5129 is trying to acquire lock:
ffff8880186e2070 (&nr_node->node_lock){+…}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff8880186e2070 (&nr_node->node_lock){+…}-{2:2}, at: nr_node_lock include/net/netrom.h:152 [inline]
ffff8880186e2070 (&nr_node->node_lock){+…}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:464 [inline]
ffff8880186e2070 (&nr_node->node_lock){+…}-{2:2}, at: nr_rt_ioctl+0x1bb/0x1090 net/netrom/nr_route.c:697
but task is already holding lock:
ffffffff8f7053b8 (nr_node_list_lock){+…}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffffffff8f7053b8 (nr_node_list_lock){+…}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:462 [inline]
ffffffff8f7053b8 (nr_node_list_lock){+…}-{2:2}, at: nr_rt_ioctl+0x10a/0x1090 net/netrom/nr_route.c:697
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (nr_node_list_lock){+…}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nr_remove_node net/netrom/nr_route.c:299 [inline]
nr_del_node+0x4b4/0x820 net/netrom/nr_route.c:355
nr_rt_ioctl+0xa95/0x1090 net/netrom/nr_route.c:683
sock_do_ioctl+0x158/0x460 net/socket.c:1222
sock_ioctl+0x629/0x8e0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&nr_node->node_lock){+…}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
nr_node_lock include/net/netrom.h:152 [inline]
nr_dec_obs net/netrom/nr_route.c:464 [inline]
nr_rt_ioctl+0x1bb/0x1090 net/netrom/nr_route.c:697
sock_do_ioctl+0x158/0x460 net/socket.c:1222
sock_ioctl+0x629/0x8e0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(nr_node_list_lock);
lock(&nr_node->node_lock);
lock(nr_node_list_lock);
lock(&nr_node->node_lock);
*** DEADLOCK***
1 lock held by syz-executor350/5129:
#0: ffffffff8f7053b8 (nr_node_list_lock){+…}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#0: ffffffff8f7053b8 (nr_node_list_lock){+…}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:462 [inline]
#0: ffffffff8f70
—truncated—
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/netrom/nr_route.c"
],
"versions": [
{
"version": "1da177e4c3f4",
"lessThan": "b9d663fbf742",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "1fbfb483c1a2",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "b117e5b4f27c",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "421c50fa8183",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "3db2fc45d1d2",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "f28bdc2ee5d9",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "5fb7e2a4335f",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "5bc50a705cfa",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "e03e7f20ebf7",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"net/netrom/nr_route.c"
],
"versions": [
{
"version": "2.6.12",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.12",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "4.19.316",
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.4.278",
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.219",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.161",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.1.93",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.33",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.8.12",
"lessThanOrEqual": "6.8.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.9.3",
"lessThanOrEqual": "6.9.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.10-rc1",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]
git.kernel.org/stable/c/1fbfb483c1a290dce3f41f52d45cc46dd88b7691
git.kernel.org/stable/c/3db2fc45d1d2a6457f06ebdfd45b9820e5b5c2b7
git.kernel.org/stable/c/421c50fa81836775bf0fd6ce0e57a6eb27af24d5
git.kernel.org/stable/c/5bc50a705cfac8f64ce51c95611c3dd0554ef9c3
git.kernel.org/stable/c/5fb7e2a4335fc67d6952ad2a6613c46e0b05f7c5
git.kernel.org/stable/c/b117e5b4f27c2c9076561b6be450a9619f0b79de
git.kernel.org/stable/c/b9d663fbf74290cb68fbc66ae4367bd56837ad1d
git.kernel.org/stable/c/e03e7f20ebf7e1611d40d1fdc1bde900fd3335f6
git.kernel.org/stable/c/f28bdc2ee5d9300cc77bd3d97b5b3cdd14960fd8