ALSA: seq: midi: Serialize input teardown with event_input
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: midi: Serialize input teardown with event_input snd_midi_input_event() must not be running while a rawmidi substream is closing, since this can lead to the trigger state becoming out-of-step through this sequence in snd_rawmidi_input_trigger(): snd_rawmidi_input_trigger(up=0) snd_midi_input_event() -> snd_rawmidi_kernel_read() -> snd_rawmidi_input_trigger(up=1) -> cancel_work_sync() which ends with the underlying device being active unexpectedly. When this is called from close_substream(), further input can re-trigger the input event leaving it running after rawmidi_release_priv() has set rfile->rmidi to NULL which leads to: Unable to handle kernel NULL pointer dereference at virtual address 00000000000000b0 Call trace: snd_midi_input_event+0x3c/0x134 [snd_seq_midi] (P) snd_rawmidi_input_event_work+0x1c/0x2c process_one_work+0x150/0x3a4 worker_thread+0x190/0x318 Apply a similar approach to commit ef7607ab1c8ad ("ALSA: seq: midi: Serialize output teardown with event_input") which fixed the same issue in the output direction, but updated to use RCU following Takashi Iwai's proposed follow-on patch [1]. With this change in place, midisynth_unsubscribe() clears the input file so snd_midi_input_event() will not re-trigger the stream and will be quiesced by the cancel_work_sync() in snd_rawmidi_input_trigger(). [1] https://lore.kernel.org/linux-sound/20260813144224.753399-1-tiwai@suse.de/
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in de76a2b47582cd6dba2e15f024681bf377ecc94a; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 89d986897aff7275b42e075e556731b8353366af; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 6290afaae54c7a9fa3bca3b4d5433e6d83e8669d; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 210c193a9ef1312fab153948c6928e4cfaa1f03b; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 282a3ef9e4b63b2f6823bbbb3c1a90b002cdaf12; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 403f7f3ad3808a0096d84cf228fab68dc253fd9d
- Linux Linux
2.6.12
- KernelLinux
From 2.6.12 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6