Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: binder: fix UAF in binder_thread_release() When a thread exits, binder_thread_release() walks its transaction stack to clear the t->from and t->to_proc that correspond with the exiting thread. However, a process dying in parallel might attempt to kfree some of these transactions. And if one of them has no associated t->to_proc, the t->to_proc->inner_lock will not be acquired. This means that transaction accesses in binder_thread_release() after t->to_proc has been cleared might race with binder_free_transaction() and cause a use-after-free error as reported by KASAN: ================================================================== BUG: KASAN: slab-use-after-free in binder_thread_release+0x5d0/0x798 Write of size 8 at addr ffff000016627500 by task X/715 CPU: 17 UID: 0 PID: 715 Comm: X Not tainted 7.1.0-rc5-00149-g8fde5d1d47f6 #30 PREEMPT Hardware name: linux,dummy-virt (DT) Call trace: binder_thread_release+0x5d0/0x798 binder_ioctl+0x12c0/0x299c [...] Allocated by task 717 on cpu 18 at 67.267803s: __kasan_kmalloc+0xa0/0xbc __kmalloc_cache_noprof+0x174/0x444 binder_transaction+0x554/0x8150 binder_thread_write+0xa30/0x4354 binder_ioctl+0x20f0/0x299c [...] Freed by task 202 on cpu 18 at 90.416221s: __kasan_slab_free+0x58/0x80 kfree+0x1a0/0x4a4 binder_free_transaction+0x150/0x294 binder_send_failed_reply+0x398/0x6d8 binder_release_work+0x3e4/0x4ec binder_deferred_func+0xbd8/0x104c [...] ================================================================== In order to avoid this, make sure that binder_free_transaction() reads the t->to_proc under the transaction lock. This will serialize the transaction release with the accesses in binder_thread_release(). Plus, it matches the documented locking rules for @to_proc.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 7a4408c6bd3eb1dafba67986259191be081e3efb before 1f96f8c0a6ed4f6d01d3dd29ad0cbf08dde96082; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before df1a17abba8d6fac5f965adcb8113ceace6e4949; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before 38e1a71728e5795b670cc159c18e286a40aeebb4; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before faa070c7ad8ba25dcd0b12d7cdbb419e336f5391; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before e63032dc715026a96bcaa13d375a8e15c91caa84; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before ea02df466df60ecd758eb3b4df3f0cadc5c886ce; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before ef5439ba5b9ac93349f5df12ef88b42a0ce26340; affected 7a4408c6bd3eb1dafba67986259191be081e3efb before 114a116aaa5f0295376cdf12da743c5bce3b20ce |
| Linux / Linux | affected 4.14; unaffected 0 before 4.14; unaffected 5.10.261 through 5.10.*; unaffected 5.15.212 through 5.15.*; unaffected 6.1.178 through 6.1.*; unaffected 6.6.145 through 6.6.*; unaffected 6.12.96 through 6.12.*; unaffected 6.18.39 through 6.18.*; unaffected 7.1.4 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/1f96f8c0a6ed4f6d01d3dd29ad0cbf08dde96082
- https://git.kernel.org/stable/c/df1a17abba8d6fac5f965adcb8113ceace6e4949
- https://git.kernel.org/stable/c/38e1a71728e5795b670cc159c18e286a40aeebb4
- https://git.kernel.org/stable/c/faa070c7ad8ba25dcd0b12d7cdbb419e336f5391
- https://git.kernel.org/stable/c/e63032dc715026a96bcaa13d375a8e15c91caa84
- https://git.kernel.org/stable/c/ea02df466df60ecd758eb3b4df3f0cadc5c886ce
- https://git.kernel.org/stable/c/ef5439ba5b9ac93349f5df12ef88b42a0ce26340
- https://git.kernel.org/stable/c/114a116aaa5f0295376cdf12da743c5bce3b20ce