Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: pinmux: fix race causing mux_owner NULL with active mux_usecount commit 5a3e85c3c397 ("pinmux: Use sequential access to access desc->pinmux data") tried to address the issue when two client of the same gpio calls pinctrl_select_state() for the same functionality, was resulting in NULL pointer issue while accessing desc->mux_owner. However, issue was not completely fixed due to the way it was handled and it can still result in the same NULL pointer. The issue occurs due to the following interleaving: cpu0 (process A) cpu1 (process B) pin_request() { pin_free() { mutex_lock() desc->mux_usecount--; //becomes 0 .. mutex_unlock() mutex_lock(desc->mux) desc->mux_usecount++; // becomes 1 desc->mux_owner = owner; mutex_unlock(desc->mux) mutex_lock(desc->mux) desc->mux_owner = NULL; mutex_unlock(desc->mux) This sequence leads to a state where the pin appears to be in use (`mux_usecount == 1`) but has no owner (`mux_owner == NULL`), which can cause NULL pointer on next pin_request on the same pin. Ensure that updates to mux_usecount and mux_owner are performed atomically under the same lock. Only clear mux_owner when mux_usecount reaches zero and no new owner has been assigned.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 2da32aed4a97ca1d70fb8b77926f72f30ce5fb4b before 9b2a3e7189028aa7c4d53a84364f2ea9fb209787; affected c11e2ec9a780f54982a187ee10ffd1b810715c85 before 9ea3f6b9a67be3476e331ce51cac316c2614a564; affected 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e before b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804; affected 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e before 22b585cbd67d14df3b91529d1b990661c300faa9; affected 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e before 0b075c011032f88d1cfde3b45d6dcf08b44140eb; affected 6.6.66 before 6.6.102; affected 6.12.5 before 6.12.42 |
| Linux / Linux | affected 6.13; unaffected 0 before 6.13; unaffected 6.6.102 through 6.6.*; unaffected 6.12.42 through 6.12.*; unaffected 6.15.10 through 6.15.*; unaffected 6.16.1 through 6.16.*; unaffected 6.17 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/9b2a3e7189028aa7c4d53a84364f2ea9fb209787
- https://git.kernel.org/stable/c/9ea3f6b9a67be3476e331ce51cac316c2614a564
- https://git.kernel.org/stable/c/b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804
- https://git.kernel.org/stable/c/22b585cbd67d14df3b91529d1b990661c300faa9
- https://git.kernel.org/stable/c/0b075c011032f88d1cfde3b45d6dcf08b44140eb