Fixed
Created: Feb 27, 2025
Updated: Apr 7, 2025
Resolved Date: Mar 24, 2025
Found In Version: 10.23.30.1
Fix Version: 10.23.30.16
Severity: Standard
Applicable for: Wind River Linux LTS 23
Component/s: Kernel
In the Linux kernel, the following vulnerability has been resolved:ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockoptIf an AX25 device is bound to a socket by setting the SO_BINDTODEVICEsocket option, a refcount leak will occur in ax25_release().Commit 9fd75b66b8f6 ("ax25: Fix refcount leaks caused by ax25_cb_del()")added decrement of device refcounts in ax25_release(). In order for thatto work correctly the refcounts must already be incremented when thedevice is bound to the socket. An AX25 device can be bound to a socketby either calling ax25_bind() or setting SO_BINDTODEVICE socket option.In both cases the refcounts should be incremented, but in fact it is doneonly in ax25_bind().This bug leads to the following issue reported by Syzkaller:================================================================refcount_t: decrement hit 0; leaking memory.WARNING: CPU: 1 PID: 5932 at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31Modules linked in:CPU: 1 UID: 0 PID: 5932 Comm: syz-executor424 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014RIP: 0010:refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31Call Trace: <TASK> __refcount_dec include/linux/refcount.h:336 inline] refcount_dec include/linux/refcount.h:351 [inline] ref_tracker_free+0x710/0x820 lib/ref_tracker.c:236 netdev_tracker_free include/linux/netdevice.h:4156 [inline] netdev_put include/linux/netdevice.h:4173 [inline] netdev_put include/linux/netdevice.h:4169 [inline] ax25_release+0x33f/0xa10 net/ax25/af_ax25.c:1069 __sock_release+0xb0/0x270 net/socket.c:640 sock_close+0x1c/0x30 net/socket.c:1408 ... do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... </TASK>================================================================Fix the implementation of ax25_setsockopt() by adding increment ofrefcounts for the new device bound, and decrement of refcounts forthe old unbound device.
CREATE(Triage):(User=admin) [CVE-2025-21792 (https://nvd.nist.gov/vuln/detail/CVE-2025-21792)
