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| author | Takashi Iwai <tiwai@suse.de> | 2018-06-25 11:13:59 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-06-25 11:18:04 +0200 |
| commit | c9a4c63888dbb79ce4d068ca1dd8b05bc3f156b1 (patch) | |
| tree | 6fa18ca5e190854952bdb5ba7c4fcb7b8d2b9acc /sound/core/seq | |
| parent | b41f794f284966fd6ec634111e3b40d241389f96 (diff) | |
ALSA: seq: Fix UBSAN warning at SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT ioctl
The kernel may spew a WARNING with UBSAN undefined behavior at
handling ALSA sequencer ioctl SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT:
UBSAN: Undefined behaviour in sound/core/seq/seq_clientmgr.c:2007:14
signed integer overflow:
2147483647 + 1 cannot be represented in type 'int'
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x122/0x1c8 lib/dump_stack.c:113
ubsan_epilogue+0x12/0x86 lib/ubsan.c:159
handle_overflow+0x1c2/0x21f lib/ubsan.c:190
__ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:198
snd_seq_ioctl_query_next_client+0x1ac/0x1d0 sound/core/seq/seq_clientmgr.c:2007
snd_seq_ioctl+0x264/0x3d0 sound/core/seq/seq_clientmgr.c:2144
....
It happens only when INT_MAX is passed there, as we're incrementing it
unconditionally. So the fix is trivial, check the value with
INT_MAX. Although the bug itself is fairly harmless, it's better to
fix it so that fuzzers won't hit this again later.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200211
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/seq')
| -rw-r--r-- | sound/core/seq/seq_clientmgr.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index 61a07fe34cd2..56ca78423040 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -2004,7 +2004,8 @@ static int snd_seq_ioctl_query_next_client(struct snd_seq_client *client, struct snd_seq_client *cptr = NULL; /* search for next client */ - info->client++; + if (info->client < INT_MAX) + info->client++; if (info->client < 0) info->client = 0; for (; info->client < SNDRV_SEQ_MAX_CLIENTS; info->client++) { |