Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: aloop: Fix racy access at PCM trigger The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers. For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF.

Weaknesses 1

Affected Products 10

References 3

• git.kernel.org https://git.kernel.org/stable/c/5727ccf9d19ca414cb76d9b647883822e2789c2e
  Patch
• git.kernel.org https://git.kernel.org/stable/c/826af7fa62e347464b1b4e0ba2fe19a92438084f
  Patch
• git.kernel.org https://git.kernel.org/stable/c/bad15420050db1803767e58756114800cce91ea4
  Patch

Remediation

• git.kernel.org https://git.kernel.org/stable/c/5727ccf9d19ca414cb76d9b647883822e2789c2e
  Patch
• git.kernel.org https://git.kernel.org/stable/c/826af7fa62e347464b1b4e0ba2fe19a92438084f
  Patch
• git.kernel.org https://git.kernel.org/stable/c/bad15420050db1803767e58756114800cce91ea4
  Patch