In the Linux kernel, the following vulnerability has been resolved:
ALSA: ump: fix double free of out_cvts on rawmidi error
snd_ump_attach_legacy_rawmidi() allocates the legacy conversion array ump->out_cvts and, on the snd_rawmidi_new() error path, frees it with kfree() but leaves ump->out_cvts pointing at the freed memory. When the endpoint is later torn down, snd_ump_endpoint_free() frees ump->out_cvts a second time, resulting in a double free.
The host snd-usb-audio driver attaches the legacy rawmidi for any USB MIDI 2.0 (UMP) device, so a device that makes snd_rawmidi_new() fail reaches this path on enumeration.
Clear ump->out_cvts after freeing it on the error path so it is not freed again during teardown.
Discovered by XBOW, triaged by Baul Lee baul.lee@xbow.com
References
- https://git.kernel.org/stable/c/032746c2dd9a4ea0774b04ac8a29e2ea628f106e
- https://git.kernel.org/stable/c/3302aaeac4f7ee6b775850db21d5f61064ce70ad
- https://git.kernel.org/stable/c/70c977815af0d997feb2d0c5d284d55689bf7051
- https://git.kernel.org/stable/c/c57001f55f97ef856fb6527e376c5c4a056a53a4
- https://git.kernel.org/stable/c/e84d2e53a05c78a04d1343eeb0f31a79456e79fc