[ Upstream commit ef7607ab1c8adc6258fb1b27d08e26aecdc18a58 ]
event_process_midi() borrows msynth->output_rfile.output and then
passes the substream to dump_midi() and snd_rawmidi_kernel_write()
without synchronizing with the output open/close transition.
midisynth_use() also publishes output_rfile before
snd_rawmidi_output_params() has finished.
The last midisynth_unuse() can therefore release the same rawmidi file
and free substream->runtime before snd_rawmidi_kernel_write1() takes
its runtime buffer reference. That leaves the event_input path using a
stale substream or runtime and can end in a NULL-deref or use-after-free.
Fix this with two pieces of synchronization. Keep a short IRQ-safe
spinlock only for publishing or clearing output_rfile and for pairing
the output snapshot with an snd_use_lock_t reference. Once
event_process_midi() has taken that in-flight reference, it drops the
spinlock before calling snd_seq_dump_var_event(), dump_midi(), or
snd_rawmidi_kernel_write(). midisynth_unuse() now detaches the visible
rawmidi file under the same spinlock, waits for the in-flight writers
to drain, and only then drains and releases the saved file.
midisynth_use() likewise opens into a local snd_rawmidi_file and
publishes it only after snd_rawmidi_output_params() succeeds.
The buggy scenario involves two paths, with each column showing the
order within that path:
event_input path: last unuse path:
1. event_process_midi() snapshots 1. midisynth_unuse() starts
output_rfile.output. tearing down output_rfile.
2. dump_midi() reaches 2. snd_rawmidi_kernel_release()
snd_rawmidi_kernel_write() closes the output file.
before runtime is pinned. 3. close_substream() frees
3. The callback keeps using substream->runtime.
the borrowed substream.
Validation reproduced this kernel report:
KASAN null-ptr-deref in snd_rawmidi_kernel_write1+0x56/0x360
RIP: 0033:0x7fde7dd0837f
RIP: 0010:snd_rawmidi_kernel_write1+0x56/0x360
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Assisted-by: Codex:gpt-5.5
Signed-off-by: Zhang Cen <rollkingzzc@gmail.com>
Link: https://patch.msgid.link/20260527062948.3614025-1-rollkingzzc@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org>
We used to have a variable declaration with __free() initialized with
NULL. This was to keep the old coding style rule, but recently it's
relaxed and rather recommends to follow the new rule to declare in
place of use for __free() -- which avoids potential deadlocks or UAFs
with nested cleanups.
Although the current code has no bug, per se, let's follow the new
standard and move the declaration to the place of assignment (or
directly assign the allocated result) instead of NULL initializations.
Note that there is a remaining __free() with NULL initialization; it's
because of the non-trivial code conditionally assigning the data.
Fixes: 04a86185b785 ("ALSA: seq: Clean up queue locking with auto cleanup")
Fixes: 0869afc958a0 ("ALSA: seq: Clean up port locking with auto cleanup")
Fixes: 99e16633958b ("ALSA: seq: Use auto-cleanup for client refcounting")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20251216140634.171890-7-tiwai@suse.de
The snd_seq bus got a dedicated probe function. Make use of that. This fixes a runtime warning about the driver needing to be converted to the bus probe method. Note that the remove callback returns void now. The actual return value was ignored before (see device_remove() in drivers/base/dd.c), so there is no problem introduced by converting `return -ENODEV` to `return`. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Link: https://patch.msgid.link/054ae56db6b55eea60c8aa8f9633e8d3d180cb09.1765283601.git.u.kleine-koenig@baylibre.com
Use a safer function strscpy() instead of strcpy() for copying to arrays. Only idiomatic code replacement, and no functional changes. Signed-off-by: Takashi Iwai <tiwai@suse.de> Link: https://patch.msgid.link/20250710100727.22653-4-tiwai@suse.de
We can simplify the code gracefully with new guard() macro and co for automatic cleanup of locks. Only the code refactoring, and no functional changes. Signed-off-by: Takashi Iwai <tiwai@suse.de> Link: https://lore.kernel.org/r/20240227085306.9764-18-tiwai@suse.de
There are common patterns where a temporary buffer is allocated and freed at the exit, and those can be simplified with the recent cleanup mechanism via __free(kfree). No functional changes, only code refactoring. Signed-off-by: Takashi Iwai <tiwai@suse.de> Link: https://lore.kernel.org/r/20240222111509.28390-10-tiwai@suse.de
clang-16 points out a control flow integrity (kcfi) issue when event
callbacks get converted to incompatible types:
sound/core/seq/seq_midi.c:135:30: error: cast from 'int (*)(struct snd_rawmidi_substream *, const char *, int)' to 'snd_seq_dump_func_t' (aka 'int (*)(void *, void *, int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
135 | snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/core/seq/seq_virmidi.c:83:31: error: cast from 'int (*)(struct snd_rawmidi_substream *, const unsigned char *, int)' to 'snd_seq_dump_func_t' (aka 'int (*)(void *, void *, int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
83 | snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For addressing those errors, introduce wrapper functions that are used
for callbacks and bridge to the actual function call with pointer
cast.
The code was originally added with the initial ALSA merge in linux-2.5.4.
[ the patch description shamelessly copied from Arnd's original patch
-- tiwai ]
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240213101020.459183-1-arnd@kernel.org
Link: https://lore.kernel.org/r/20240213135343.16411-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The compile warnings with -Wformat-truncation appearing at snd_seq_midisynth_probe() in seq_midi.c are false-positive; those must fit within the given string size. For suppressing the warning, replace snprintf() with scnprintf(). As stated in the above, truncation doesn't matter. Link: https://lore.kernel.org/r/20230915082802.28684-3-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>