cbcvebase.
CVE-2022-49272
published 2025-02-26

CVE-2022-49272: In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock syzbot caught a…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.20%
10.1th percentile
In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock syzbot caught a potential deadlock between the PCM runtime->buffer_mutex and the mm->mmap_lock. It was brought by the recent fix to cover the racy read/write and other ioctls, and in that commit, I overlooked a (hopefully only) corner case that may take the revert lock, namely, the OSS mmap. The OSS mmap operation exceptionally allows to re-configure the parameters inside the OSS mmap syscall, where mm->mmap_mutex is already held. Meanwhile, the copy_from/to_user calls at read/write operations also take the mm->mmap_lock internally, hence it may lead to a AB/BA deadlock. A similar problem was already seen in the past and we fixed it with a refcount (in commit b248371628aa). The former fix covered only the call paths with OSS read/write and OSS ioctls, while we need to cover the concurrent access via both ALSA and OSS APIs now. This patch addresses the problem above by replacing the buffer_mutex lock in the read/write operations with a refcount similar as we've used for OSS. The new field, runtime->buffer_accessing, keeps the number of concurrent read/write operations. Unlike the former buffer_mutex protection, this protects only around the copy_from/to_user() calls; the other codes are basically protected by the PCM stream lock. The refcount can be a negative, meaning blocked by the ioctls. If a negative value is seen, the read/write aborts with -EBUSY. In the ioctl side, OTOH, they check this refcount, too, and set to a negative value for blocking unless it's already being accessed.

Affected

21 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.17.3-1 (bookworm)linux 5.17.3-1 (bookworm)
linuxlinux>= 08d1807f097a63ea00a7067dad89c1c81cb2115e < 9661bf674d6a82b76e4ae424438a8ce1e3ed855d9661bf674d6a82b76e4ae424438a8ce1e3ed855d
linuxlinux>= 47711ff10c7e126702cfa725f6d86ef529d15a5f < 7777744e92a0b30e3e0cce2758d911837011ebd97777744e92a0b30e3e0cce2758d911837011ebd9
linuxlinux>= 4d1b0ace2d56dc27cc4921eda7fae57f77f03eb5 < abedf0d08c79d76da0d6fa0d5dbbc98871dcbc2eabedf0d08c79d76da0d6fa0d5dbbc98871dcbc2e
linuxlinux>= 5.10.109 < 5.10.1105.10.110
linuxlinux>= 5.15.32 < 5.15.335.15.33
linuxlinux>= 5.16.18 < 5.16.195.16.19
linuxlinux>= 5.17.1 < 5.17.25.17.2
linuxlinux>= 73867cb2bc7dfa7fbd219e53a0b68d253d8fda09 < 7e9133607e1501c94881be35e118d8f84d96dcb47e9133607e1501c94881be35e118d8f84d96dcb4
linuxlinux>= 8527c8f052fb42091c6569cb928e472376a4a889 < 9017201e8d8c6d1472273361389ed431188584a09017201e8d8c6d1472273361389ed431188584a0
linuxlinux>= b3830197aa7413c65767cf5a1aa8775c83f0dbf7 < 40f4cffbe13a51faf136faf5f9ef6847782cd59540f4cffbe13a51faf136faf5f9ef6847782cd595
linuxlinux>= dca947d4d26dbf925a64a6cfb2ddbc035e831a3d < bc55cfd5718c7c23e5524582e9fa70b4d10f2433bc55cfd5718c7c23e5524582e9fa70b4d10f2433
linuxlinux>= dd2f8c684da3e226e5ec7a81c89ff5fd4a957a03 < be9813ad2fc8f0885f5ce6925af0d993ce5da4e5be9813ad2fc8f0885f5ce6925af0d993ce5da4e5
linuxlinux_kernel——
linuxlinux_kernel——
linuxlinux_kernel——
linuxlinux_kernel——
linuxlinux_kernel>= 0 < 5.10.113-15.10.113-1
linuxlinux_kernel>= 0 < 5.17.3-15.17.3-1
linuxlinux_kernel>= 0 < 5.17.3-15.17.3-1
linuxlinux_kernel>= 0 < 5.17.3-15.17.3-1

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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