From cf59e1e4c79bf741905484cdb13c130b53576a16 Mon Sep 17 00:00:00 2001

From: Baisong Zhong <zhongbaisong@huawei.com>

Date: Mon, 21 Nov 2022 19:16:30 +0800

Subject: [PATCH] ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT

Git-commit: cf59e1e4c79bf741905484cdb13c130b53576a16

Patch-mainline: v6.2-rc1

References: git-fixes

Shifting signed 32-bit value by 31 bits is undefined, so changing

significant bit to unsigned. The UBSAN warning calltrace like below:

Ubsan: shift-out-of-bounds in sound/core/seq/seq_clientmgr.c:509:22

left shift of 1 by 31 places cannot be represented in type 'int'

...

Call Trace:

 <TASK>

 dump_stack_lvl+0x8d/0xcf

 ubsan_epilogue+0xa/0x44

 __ubsan_handle_shift_out_of_bounds+0x1e7/0x208

 snd_seq_deliver_single_event.constprop.21+0x191/0x2f0

 snd_seq_deliver_event+0x1a2/0x350

 snd_seq_kernel_client_dispatch+0x8b/0xb0

 snd_seq_client_notify_subscription+0x72/0xa0

 snd_seq_ioctl_subscribe_port+0x128/0x160

 snd_seq_kernel_client_ctl+0xce/0xf0

 snd_seq_oss_create_client+0x109/0x15b

 alsa_seq_oss_init+0x11c/0x1aa

 do_one_initcall+0x80/0x440

 kernel_init_freeable+0x370/0x3c3

 kernel_init+0x1b/0x190

 ret_from_fork+0x1f/0x30

 </TASK>

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

Signed-off-by: Baisong Zhong <zhongbaisong@huawei.com>

Link: https://lore.kernel.org/r/20221121111630.3119259-1-zhongbaisong@huawei.com

Signed-off-by: Takashi Iwai <tiwai@suse.de>

---

 include/uapi/sound/asequencer.h | 8 ++++----

 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/uapi/sound/asequencer.h b/include/uapi/sound/asequencer.h

index 6d4a2c60808d..00d2703e8fca 100644

--- a/include/uapi/sound/asequencer.h

+++ b/include/uapi/sound/asequencer.h

@@ -328,10 +328,10 @@ typedef int __bitwise snd_seq_client_type_t;

 #define	KERNEL_CLIENT	((__force snd_seq_client_type_t) 2)

 	/* event filter flags */

-#define SNDRV_SEQ_FILTER_BROADCAST	(1<<0)	/* accept broadcast messages */

-#define SNDRV_SEQ_FILTER_MULTICAST	(1<<1)	/* accept multicast messages */

-#define SNDRV_SEQ_FILTER_BOUNCE		(1<<2)	/* accept bounce event in error */

-#define SNDRV_SEQ_FILTER_USE_EVENT	(1<<31)	/* use event filter */

+#define SNDRV_SEQ_FILTER_BROADCAST	(1U<<0)	/* accept broadcast messages */

+#define SNDRV_SEQ_FILTER_MULTICAST	(1U<<1)	/* accept multicast messages */

+#define SNDRV_SEQ_FILTER_BOUNCE		(1U<<2)	/* accept bounce event in error */

+#define SNDRV_SEQ_FILTER_USE_EVENT	(1U<<31)	/* use event filter */

 struct snd_seq_client_info {

 	int client;			/* client number to inquire */

-- 

2.35.3