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authorTakashi Iwai <tiwai@suse.de>2018-06-25 11:13:59 +0200
committerTakashi Iwai <tiwai@suse.de>2018-06-25 11:18:04 +0200
commitc9a4c63888dbb79ce4d068ca1dd8b05bc3f156b1 (patch)
tree6fa18ca5e190854952bdb5ba7c4fcb7b8d2b9acc /sound
parentALSA: timer: Fix UBSAN warning at SNDRV_TIMER_IOCTL_NEXT_DEVICE ioctl (diff)
downloadlinux-dev-c9a4c63888dbb79ce4d068ca1dd8b05bc3f156b1.tar.xz
linux-dev-c9a4c63888dbb79ce4d068ca1dd8b05bc3f156b1.zip
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')
-rw-r--r--sound/core/seq/seq_clientmgr.c3
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++) {