This is a note to let you know that I've just added the patch titled ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-seq-fix-undefined-behavior-in-bit-shift-for-snd.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f15825088dbaf3a176621679370556f8ae07a730 Author: Baisong Zhong <zhongbaisong@xxxxxxxxxx> Date: Mon Nov 21 19:16:30 2022 +0800 ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT [ Upstream commit cf59e1e4c79bf741905484cdb13c130b53576a16 ] 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@xxxxxxxxxx> Link: https://lore.kernel.org/r/20221121111630.3119259-1-zhongbaisong@xxxxxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/include/uapi/sound/asequencer.h b/include/uapi/sound/asequencer.h index a75e14edc957..dbd60f48b4b0 100644 --- a/include/uapi/sound/asequencer.h +++ b/include/uapi/sound/asequencer.h @@ -344,10 +344,10 @@ 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 */