kernel/linux.git/sound/core, branch v5.15.212

ALSA: seq: Fix uninitialised heap leak in snd_seq_event_dup()

2026-07-24T13:52:02+00:00

commit 435990e25bf1f4af3e6df12a6fbfd1f7ba4a97d4 upstream. snd_seq_event_dup() copies an incoming event into a pool cell and, in the UMP-enabled build, clears the trailing cell->ump.raw.extra word that the memcpy() did not cover. The guard deciding whether to clear it compares the copied size against sizeof(cell->event): memcpy(&cell->ump, event, size); if (size < sizeof(cell->event)) cell->ump.raw.extra = 0; For a legacy (non-UMP) event, size == sizeof(struct snd_seq_event) == sizeof(cell->event), so the condition is false and the extra word keeps stale data. The cell pool is allocated with kvmalloc() (not zeroed) and cells are reused via a free list, so that word holds uninitialised heap or leftover event data. When such a cell is delivered to a UMP client (client->midi_version > 0) that set SNDRV_SEQ_FILTER_NO_CONVERT -- so the legacy event reaches it unconverted -- snd_seq_read() reads it out as the larger struct snd_seq_ump_event and copies the stale word to user space, a 4-byte kernel heap infoleak to an unprivileged /dev/snd/seq client. Compare against sizeof(cell->ump) instead, so the trailing word is zeroed for every event shorter than the UMP cell. Fixes: 46397622a3fa ("ALSA: seq: Add UMP support") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: HyeongJun An Link: https://patch.msgid.link/20260623233841.853326-1-sammiee5311@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Check UMP support for midi_version change

2026-07-24T13:52:02+00:00

commit 8765429279e7d3d68d39ace5f84af2815174bb1e upstream. When the kernel is built without UMP support but a user-space app requires the midi_version > 0, the kernel should return an error. Otherwise user-space assumes as if it were possible to deal, eventually hitting serious errors later. Fixes: 46397622a3fa ("ALSA: seq: Add UMP support") Cc: Link: https://patch.msgid.link/20241231145358.21946-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Skip event type filtering for UMP events

2026-07-24T13:52:02+00:00

commit 32108c22ac619c32dd6db594319e259b63bfb387 upstream. UMP events don't use the event type field, hence it's invalid to apply the filter, which may drop the events unexpectedly. Skip the event filtering for UMP events, instead. Fixes: 46397622a3fa ("ALSA: seq: Add UMP support") Cc: Link: https://patch.msgid.link/20240819084156.10286-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Avoid confusion of aligned read size

2026-07-24T13:52:02+00:00

commit 8c15a18331191b67bdce54d21af068baec044baf upstream. Currently the read event packet size in snd_seq_read() is defined by client->midi_version value that is guaranteed to be zero if UMP isn't enabled. But the static analyzer doesn't know of the fact, and it still suspects as if it were leading to a potential overflow. Add the more explicit check of CONFIG_SND_SEQ_UMP to determine the aligned_size value for avoiding the confusion. Fixes: 46397622a3fa ("ALSA: seq: Add UMP support") Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202305261415.NY0vapZK-lkp@intel.com/ Link: https://lore.kernel.org/r/20230605144758.6677-2-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Clear variable event pointer on read

2026-07-24T13:51:33+00:00

[ Upstream commit 705dd6dcbc0ea87351c660c1a6443f85f1001c76 ] snd_seq_read() copies a queued variable-length event header to userspace before expanding the payload. Queued variable-length events use SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first extension cell. The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the copy, but it leaves data.ext.ptr untouched. A userspace sequencer client can therefore write a direct variable event to itself and read back the extension-cell kernel address from the returned header. Clear the temporary header pointer before copy_to_user(). The original queued event remains unchanged and is still passed to snd_seq_expand_var_event(), so payload expansion keeps using the internal chain. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kyle Zeng Link: https://patch.msgid.link/20260607004129.61345-1-kylebot@openai.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: seq: Add UMP support

2026-07-24T13:51:33+00:00

[ Upstream commit 46397622a3fa8372b8fda0f04b33d16923b03b1b ] Starting from this commit, we add the basic support of UMP (Universal MIDI Packet) events on ALSA sequencer infrastructure. The biggest change here is that, for transferring UMP packets that are up to 128 bits, we extend the data payload of ALSA sequencer event record when the client is declared to support for the new UMP events. A new event flag bit, SNDRV_SEQ_EVENT_UMP, is defined and it shall be set for the UMP packet events that have the larger payload of 128 bits, defined as struct snd_seq_ump_event. For controlling the UMP feature enablement in kernel, a new Kconfig, CONFIG_SND_SEQ_UMP is introduced. The extended event for UMP is available only when this Kconfig item is set. Similarly, the size of the internal snd_seq_event_cell also increases (in 4 bytes) when the Kconfig item is set. (But the size increase is effective only for 32bit architectures; 64bit archs already have padding there.) Overall, when CONFIG_SND_SEQ_UMP isn't set, there is no change in the event and cell, keeping the old sizes. For applications that want to access the UMP packets, first of all, a sequencer client has to declare the user-protocol to match with the latest one via the new SNDRV_SEQ_IOCTL_USER_PVERSION; otherwise it's treated as if a legacy client without UMP support. Then the client can switch to the new UMP mode (MIDI 1.0 or MIDI 2.0) with a new field, midi_version, in snd_seq_client_info. When switched to UMP mode (midi_version = 1 or 2), the client can write the UMP events with SNDRV_SEQ_EVENT_UMP flag. For reads, the alignment size is changed from snd_seq_event (28 bytes) to snd_seq_ump_event (32 bytes). When a UMP sequencer event is delivered to a legacy sequencer client, it's ignored or handled as an error. Conceptually, ALSA sequencer client and port correspond to the UMP Endpoint and Group, respectively; each client may have multiple ports and each port has the fixed number (16) of channels, total up to 256 channels. As of this commit, ALSA sequencer core just sends and receives the UMP events as-is from/to clients. The automatic conversions between the legacy events and the new UMP events will be implemented in a later patch. Along with this commit, bump the sequencer protocol version to 1.0.3. Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20230523075358.9672-26-tiwai@suse.de Signed-off-by: Takashi Iwai Stable-dep-of: 705dd6dcbc0e ("ALSA: seq: Clear variable event pointer on read") Signed-off-by: Sasha Levin

ALSA: seq: Introduce SNDRV_SEQ_IOCTL_USER_PVERSION ioctl

2026-07-24T13:51:33+00:00

[ Upstream commit afb72505e4614a2ccefe3440d37dec3a2273c330 ] For the future extension of ALSA sequencer ABI, introduce a new ioctl SNDRV_SEQ_IOCTL_USER_PVERSION. This is similar like the ioctls used in PCM and other interfaces, for an application to specify its supporting ABI version. The use of this ioctl will be mandatory for the upcoming UMP support. Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20230523075358.9672-25-tiwai@suse.de Signed-off-by: Takashi Iwai Stable-dep-of: 705dd6dcbc0e ("ALSA: seq: Clear variable event pointer on read") Signed-off-by: Sasha Levin

ALSA: core: Fix potential data race at fasync handling

2026-06-19T11:33:41+00:00

[ Upstream commit 8146cd333d235ed32d48bb803fdf743472d7c783 ] In snd_fasync_work_fn(), which is the offload work for traversing and processing the pending fasync list, the call of kill_fasync() is done outside the snd_fasync_lock for avoiding deadlocks. The problem is that its the references of fasync->on, fasync->signal and fasync->poll are done there also outside the lock. Since these may be modified by snd_kill_fasync() call concurrently from other process, inconsistent values might be passed to kill_fasync(). Although there shouldn't be critical UAF, it's still better to be addressed. This patch moves the kill_fasync() argument evaluations inside the snd_fasync_lock for avoiding the data races above. The handling in fasync->on flag is optimized in the loop to skip directly. Also, for more clarity, snd_fasync_free() takes the lock and unlink the pending entry more directly instead of clearing fasync->on flag. Reported-by: Jake Lamberson Fixes: ef34a0ae7a26 ("ALSA: core: Add async signal helpers") Cc: Link: https://patch.msgid.link/20260420061721.3253644-1-tiwai@suse.de Signed-off-by: Takashi Iwai [ replaced scoped_guard(spinlock_irq, &snd_fasync_lock) with explicit spin_lock_irq()/spin_unlock_irq() ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ALSA: timer: Fix UAF at snd_timer_user_params()

2026-06-19T11:33:37+00:00

commit 053a401b592be424fea9d57c789f66cd5d8cec11 upstream. At releasing a timer object, e.g. when a userspace timer (CONFIG_SND_UTIMER) gets closed and snd_timer_free() is called, it tries to detach the timer instances and release the resources. However, it's still possible that other in-flight tasks are holding the timer instance where the to-be-deleted timer object is associated, and this may lead to racy accesses. Fortunately, most of ioctls dealing with the timer instance list already have the protection with register_mutex, and this also avoids such races. But, SNDRV_TIMER_IOCTL_PARAMS isn't protected, hence the concurrent ioctl may lead to use-after-free. This patch just adds the guard with register_mutex to protect snd_timer_user_params() for covering the code path as a quick workaround. It's no hot-path but rather a rarely issued ioctl, so the performance penalty doesn't matter. Reported-by: Kyle Zeng Tested-by: Kyle Zeng Cc: Link: https://patch.msgid.link/20260606161145.1933447-2-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: core: Validate compress device numbers without dynamic minors

2026-06-01T15:35:30+00:00

[ Upstream commit 796e119e9b14763be905ad0d023c71a14bc2e931 ] Without CONFIG_SND_DYNAMIC_MINORS, ALSA reserves only two fixed minors for compress devices on each card: comprD0 and comprD1. snd_find_free_minor() currently computes the compress minor as type + dev without validating dev first, so device numbers greater than 1 spill into the HWDEP minor range instead of failing registration. ASoC passes rtd->id to snd_compress_new(), so this can happen on real non-dynamic-minor builds. Add a dedicated fixed-minor check for SNDRV_DEVICE_TYPE_COMPRESS in snd_find_free_minor() and reject out-of-range device numbers with -EINVAL before constructing the minor. Also remove the stale TODO in compress_offload.c that still claims multiple compress nodes are missing. Fixes: 3eafc959b32f ("ALSA: core: add support for compressed devices") Signed-off-by: Cássio Gabriel Link: https://patch.msgid.link/20260325-alsa-compress-static-minors-v1-1-0628573bee1c@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin