Description
In the Linux kernel, the following vulnerability has been resolved: misc: nsm: only unlock nsm_dev on post-lock error paths nsm_dev_ioctl() jumps to the common out label even when the initial copy_from_user() fails before nsm->lock has been taken. The error path then blindly unlocks a mutex that was never acquired. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the miscdevice ioctl entry and the pre-lock copy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing NSM_IOCTL_RAW with an invalid user pointer. That failure reaches the shared out label before mutex_lock(&nsm->lock). Lockdep reported: WARNING: bad unlock balance detected! exploit/193 is trying to release lock (&global_nsm.lock) at: nsm_dev_ioctl+0x5f/0xcf [vuln_msv] but there are no more locks to release! no locks held by exploit/193. Return immediately on the pre-lock copy_from_user() failure and keep the common unlock label for the post-lock paths only.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
b9873755a6c8ccfce79094c4dce9efa3ecb1a749 to < 4aa3f7d48e91eb74a363c1b4d7dbdd28f5b341fbaffectedb9873755a6c8ccfce79094c4dce9efa3ecb1a749 to < 8f068342096b027181b168d91fef7ac7a2c64b25affectedb9873755a6c8ccfce79094c4dce9efa3ecb1a749 to < f318f5a872cb9096536e759b23ae5c9873bb80edaffectedb9873755a6c8ccfce79094c4dce9efa3ecb1a749 to < ce1fed11d18e163baf7f875152a33bf80f625c1aaffected
Linux Linux
Default version status: affected
6.8affected0 to < 6.8unaffected6.12.101 to ≤ 6.12.*unaffected6.18.42 to ≤ 6.18.*unaffected7.1.6 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected