CVSS 7.8 · High EPSS 0,15%
Kerentanan Use After Free pada linux kernel. Skor CVSS 3.1 7.8 (High) menurut NVD.
In the Linux kernel, the following vulnerability has been resolved: nfsd: provide locking for v4_end_grace Writing to v4_end_grace can race with server shutdown and result in memory being accessed after it was freed - reclaim_str_hashtbl in particularly. We cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is held while client_tracking_op->init() is called and that can wait for an upcall to nfsdcltrack which can write to v4_end_grace, resulting in a deadlock. nfsd4_end_grace() is also called by the landromat work queue and this doesn't require locking as server shutdown will stop the work and wait for it before freeing anything that nfsd4_end_grace() might access. However, we must be sure that writing to v4_end_grace doesn't restart the work item after shutdown has already waited for it. For this we add a new flag protected with nn->client_lock. It is set only while it is safe to make client tracking calls, and v4_end_grace only schedules work while the flag is set with the spinlock held. So this patch adds a nfsd_net field "client_tracking_active" which is set as described. Another field "grace_end_forced", is set when v4_end_grace is written. After this is set, and providing client_tracking_active is set, the laundromat is scheduled. This "grace_end_forced" field bypasses other checks for whether the grace period has finished. This resolves a race which can result in use-after-free.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 3.18 hingga sebelum 5.10.248 |
| linux | linux kernel | Versi 5.11 hingga sebelum 5.15.198 |
| linux | linux kernel | Versi 5.16 hingga sebelum 6.1.161 |
| linux | linux kernel | Versi 6.2 hingga sebelum 6.6.121 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.12.66 |
| linux | linux kernel | Versi 6.13 hingga sebelum 6.18.6 |
| linux | linux kernel | Versi 6.19 rc1 |
| linux | linux kernel | Versi 6.19 rc2 |
| linux | linux kernel | Versi 6.19 rc3 |
| linux | linux kernel | Versi 6.19 rc4 |