kernel/linux.git/include/sound/rawmidi.h, branch v4.9.331

ALSA: rawmidi: Fix racy buffer resize under concurrent accesses

2020-05-20T06:15:40+00:00

commit c1f6e3c818dd734c30f6a7eeebf232ba2cf3181d upstream. The rawmidi core allows user to resize the runtime buffer via ioctl, and this may lead to UAF when performed during concurrent reads or writes: the read/write functions unlock the runtime lock temporarily during copying form/to user-space, and that's the race window. This patch fixes the hole by introducing a reference counter for the runtime buffer read/write access and returns -EBUSY error when the resize is performed concurrently against read/write. Note that the ref count field is a simple integer instead of refcount_t here, since the all contexts accessing the buffer is basically protected with a spinlock, hence we need no expensive atomic ops. Also, note that this busy check is needed only against read / write functions, and not in receive/transmit callbacks; the race can happen only at the spinlock hole mentioned in the above, while the whole function is protected for receive / transmit callbacks. Reported-by: butt3rflyh4ck Cc: Link: https://lore.kernel.org/r/CAFcO6XMWpUVK_yzzCpp8_XP7+=oUpQvuBeCbMffEDkpe8jWrfg@mail.gmail.com Link: https://lore.kernel.org/r/s5heerw3r5z.wl-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: rawmidi: Avoid bit fields for state flags

2020-02-28T14:42:55+00:00

commit dfa9a5efe8b932a84b3b319250aa3ac60c20f876 upstream. The rawmidi state flags (opened, append, active_sensing) are stored in bit fields that can be potentially racy when concurrently accessed without any locks. Although the current code should be fine, there is also no any real benefit by keeping the bitfields for this kind of short number of members. This patch changes those bit fields flags to the simple bool fields. There should be no size increase of the snd_rawmidi_substream by this change. Reported-by: syzbot+576cc007eb9f2c968200@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20200214111316.26939-4-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: rawmidi: Make snd_rawmidi_transmit() race-free

2016-02-03T13:51:28+00:00

A kernel WARNING in snd_rawmidi_transmit_ack() is triggered by syzkaller fuzzer: WARNING: CPU: 1 PID: 20739 at sound/core/rawmidi.c:1136 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 [] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482 [] warn_slowpath_null+0x29/0x30 kernel/panic.c:515 [] snd_rawmidi_transmit_ack+0x275/0x400 sound/core/rawmidi.c:1136 [] snd_virmidi_output_trigger+0x4b1/0x5a0 sound/core/seq/seq_virmidi.c:163 [< inline >] snd_rawmidi_output_trigger sound/core/rawmidi.c:150 [] snd_rawmidi_kernel_write1+0x549/0x780 sound/core/rawmidi.c:1223 [] snd_rawmidi_write+0x543/0xb30 sound/core/rawmidi.c:1273 [] __vfs_write+0x113/0x480 fs/read_write.c:528 [] vfs_write+0x167/0x4a0 fs/read_write.c:577 [< inline >] SYSC_write fs/read_write.c:624 [] SyS_write+0x111/0x220 fs/read_write.c:616 [] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 Also a similar warning is found but in another path: Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 [] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482 [] warn_slowpath_null+0x29/0x30 kernel/panic.c:515 [] rawmidi_transmit_ack+0x24a/0x3b0 sound/core/rawmidi.c:1133 [] snd_rawmidi_transmit_ack+0x51/0x80 sound/core/rawmidi.c:1163 [] snd_virmidi_output_trigger+0x2b6/0x570 sound/core/seq/seq_virmidi.c:185 [< inline >] snd_rawmidi_output_trigger sound/core/rawmidi.c:150 [] snd_rawmidi_kernel_write1+0x4bb/0x760 sound/core/rawmidi.c:1252 [] snd_rawmidi_write+0x543/0xb30 sound/core/rawmidi.c:1302 [] __vfs_write+0x113/0x480 fs/read_write.c:528 [] vfs_write+0x167/0x4a0 fs/read_write.c:577 [< inline >] SYSC_write fs/read_write.c:624 [] SyS_write+0x111/0x220 fs/read_write.c:616 [] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 In the former case, the reason is that virmidi has an open code calling snd_rawmidi_transmit_ack() with the value calculated outside the spinlock. We may use snd_rawmidi_transmit() in a loop just for consuming the input data, but even there, there is a race between snd_rawmidi_transmit_peek() and snd_rawmidi_tranmit_ack(). Similarly in the latter case, it calls snd_rawmidi_transmit_peek() and snd_rawmidi_tranmit_ack() separately without protection, so they are racy as well. The patch tries to address these issues by the following ways: - Introduce the unlocked versions of snd_rawmidi_transmit_peek() and snd_rawmidi_transmit_ack() to be called inside the explicit lock. - Rewrite snd_rawmidi_transmit() to be race-free (the former case). - Make the split calls (the latter case) protected in the rawmidi spin lock. BugLink: http://lkml.kernel.org/r/CACT4Y+YPq1+cYLkadwjWa5XjzF1_Vki1eHnVn-Lm0hzhSpu5PA@mail.gmail.com BugLink: http://lkml.kernel.org/r/CACT4Y+acG4iyphdOZx47Nyq_VHGbpJQK-6xNpiqUjaZYqsXOGw@mail.gmail.com Reported-by: Dmitry Vyukov Tested-by: Dmitry Vyukov Cc: Signed-off-by: Takashi Iwai

ALSA: midi: constify snd_rawmidi_global_ops structures

2015-11-22T08:21:16+00:00

The snd_rawmidi_global_ops structures are never modified, so declare them as const. Done with the help of Coccinelle. Signed-off-by: Julia Lawall Signed-off-by: Takashi Iwai

ALSA: rawmidi: Embed struct device

2015-02-02T13:42:43+00:00

Like previous patches, this changes the device management for rawmidi, embedding the struct device into struct snd_rawmidi. The required change is more or less same as hwdep device. The currently unused dev field is reused as the new embedded struct field now. Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai

ALSA: rawmidi: remove undefined functions.

2014-02-21T11:06:12+00:00

'snd_rawmidi_transmit_reset()' and 'snd_rawmidi_receive_reset()' are declared but not defined. This state has been continue over 10 years. So let us remove them. Signed-off-by: Takashi Sakamoto Signed-off-by: Takashi Iwai

UAPI: (Scripted) Convert #include "..." to #include in kernel system headers

2012-10-02T17:01:25+00:00

Convert #include "..." to #include in kernel system headers. Signed-off-by: David Howells Acked-by: Arnd Bergmann Acked-by: Thomas Gleixner Acked-by: Paul E. McKenney Acked-by: Dave Jones

ALSA: rawmidi - Use workq for event handling

2011-06-14T12:37:06+00:00

Kill tasklet usage in rawmidi core code. Use workq for the event callback instead of tasklet (which is used only in core/seq/seq_midi.c). Signed-off-by: Takashi Iwai

sound: rawmidi: record a substream's owner process

2009-11-10T15:32:38+00:00

Record the pid of the task that opened a RawMIDI substream. Signed-off-by: Clemens Ladisch Signed-off-by: Takashi Iwai

ALSA: rawmidi - Refactor rawmidi open/close codes

2009-03-09T14:17:23+00:00

Refactor rawmidi open/close code messes. Signed-off-by: Takashi Iwai