Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: cuse: wait for pending RCU callbacks on module exit Since commit 053fc4f755ad ("fuse: fix UAF in rcu pathwalks"), fuse_conn_put() frees the fuse_conn through call_rcu() rather than synchronously. For cuse, fc->release is cuse_fc_release(), which lives in the cuse module. If the module is removed before the RCU grace period ends, the callback jumps into freed module memory: userspace / module unload | RCU softirq ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ close(/dev/cuse) | cuse_channel_release() | fuse_dev_release() | fuse_conn_put(fch->conn) | call_rcu(delayed_release) ------+---> callback queued | rmmod cuse | cuse_exit() | cuse_channel_destroy() | ... | return | | <module text freed> | | rcu_do_batch() | delayed_release() | fc->release() | -> cuse_fc_release() | ^^^ freed text! The freed module text is unmapped by vfree(), so the jump into the stale callback triggers a page-fault Oops. If the virtual address is subsequently reused, the callback could execute unrelated code (undefined behaviour). Fix this by calling rcu_barrier() in cuse_exit() so that any pending fuse_conn release callback completes before the module is removed.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected bfbab62ca69f72bcd14ea30de1fb98f6080ad464 before 7fe415e1cd8fa875be263670c0ab47109818abb6; affected a8f650b93e55764ca9ff8e1ddebc151f57024086 before 45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e; affected 535e9bd0e8f8d8cfdc29de7cdb902b5041427fe6 before ac5c499413385cea3e0220d6050408d50842891d; affected 053fc4f755ad43cf35210677bcba798ccdc48d0c before a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9; affected 053fc4f755ad43cf35210677bcba798ccdc48d0c before 389bd349ddbcf90dbd8a4f2a4ab6e552d53df134; affected 053fc4f755ad43cf35210677bcba798ccdc48d0c before c40f3f24839f8404325a2099e26c2a04786ae309; affected 053fc4f755ad43cf35210677bcba798ccdc48d0c before 4deb3edead0c0e172cc7349e8855d741d3c5e162; affected 5.15.166 before 5.15.221; affected 6.1.107 before 6.1.188; affected 6.6.48 before 6.6.157 |
| Linux / Linux | affected 6.8; unaffected 0 before 6.8; unaffected 5.15.221 through 5.15.*; unaffected 6.1.188 through 6.1.*; unaffected 6.6.157 through 6.6.*; unaffected 6.12.110 through 6.12.*; unaffected 6.18.52 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/7fe415e1cd8fa875be263670c0ab47109818abb6
- https://git.kernel.org/stable/c/45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e
- https://git.kernel.org/stable/c/ac5c499413385cea3e0220d6050408d50842891d
- https://git.kernel.org/stable/c/a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9
- https://git.kernel.org/stable/c/389bd349ddbcf90dbd8a4f2a4ab6e552d53df134
- https://git.kernel.org/stable/c/c40f3f24839f8404325a2099e26c2a04786ae309
- https://git.kernel.org/stable/c/4deb3edead0c0e172cc7349e8855d741d3c5e162