Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ax25: Fix refcount imbalance on inbound connections When releasing a socket in ax25_release(), we call netdev_put() to decrease the refcount on the associated ax.25 device. However, the execution path for accepting an incoming connection never calls netdev_hold(). This imbalance leads to refcount errors, and ultimately to kernel crashes. A typical call trace for the above situation will start with one of the following errors: refcount_t: decrement hit 0; leaking memory. refcount_t: underflow; use-after-free. And will then have a trace like: Call Trace: <TASK> ? show_regs+0x64/0x70 ? __warn+0x83/0x120 ? refcount_warn_saturate+0xb2/0x100 ? report_bug+0x158/0x190 ? prb_read_valid+0x20/0x30 ? handle_bug+0x3e/0x70 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? refcount_warn_saturate+0xb2/0x100 ? refcount_warn_saturate+0xb2/0x100 ax25_release+0x2ad/0x360 __sock_release+0x35/0xa0 sock_close+0x19/0x20 [...] On reboot (or any attempt to remove the interface), the kernel gets stuck in an infinite loop: unregister_netdevice: waiting for ax0 to become free. Usage count = 0 This patch corrects these issues by ensuring that we call netdev_hold() and ax25_dev_hold() for new connections in ax25_accept(). This makes the logic leading to ax25_accept() match the logic for ax25_bind(): in both cases we increment the refcount, which is ultimately decremented in ax25_release().
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 9fd75b66b8f68498454d685dc4ba13192ae069b0 before f4df9d6c8d4e4c818252b0419c2165d66eabd4eb; affected 9fd75b66b8f68498454d685dc4ba13192ae069b0 before 52100fd74ad07b53a4666feafff1cd11436362d3; affected 9fd75b66b8f68498454d685dc4ba13192ae069b0 before a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964; affected 9fd75b66b8f68498454d685dc4ba13192ae069b0 before 3c34fb0bd4a4237592c5ecb5b2e2531900c55774; affected c44a453ffe16eb08acdc6129ac4fa0192dbc0456; affected de55a1338e6a48ff1e41ea8db1432496fbe2a62b; affected 9e1e088a57c23251f1cfe9601bbd90ade2ea73b9; affected b20a5ab0f5fb175750c6bafd4cf12daccf00c738; affected 452ae92b99062d2f6a34324eaf705a3b7eac9f8b; affected 534156dd4ed768e30a43de0036f45dca7c54818f; affected 4.14.277 before 4.15; affected 4.19.240 before 4.20; affected 5.4.190 before 5.5; affected 5.10.112 before 5.11; affected 5.15.35 before 5.16; affected 5.17.2 before 5.18 |
| Linux / Linux | affected 5.18; unaffected 0 before 5.18; unaffected 6.1.95 through 6.1.*; unaffected 6.6.35 through 6.6.*; unaffected 6.9.6 through 6.9.*; unaffected 6.10 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/f4df9d6c8d4e4c818252b0419c2165d66eabd4eb
- https://git.kernel.org/stable/c/52100fd74ad07b53a4666feafff1cd11436362d3
- https://git.kernel.org/stable/c/a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964
- https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774
ADP enrichment
No English description supplied.
- https://git.kernel.org/stable/c/f4df9d6c8d4e4c818252b0419c2165d66eabd4eb
- https://git.kernel.org/stable/c/52100fd74ad07b53a4666feafff1cd11436362d3
- https://git.kernel.org/stable/c/a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964
- https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
No English description supplied.
No references supplied.