[v1] ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT

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

Posted by Baisong Zhong 3 years, 4 months ago

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>
---
 include/uapi/sound/asequencer.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/sound/asequencer.h b/include/uapi/sound/asequencer.h
index 6d4a2c60808d..4c5c4dd15d02 100644
--- a/include/uapi/sound/asequencer.h
+++ b/include/uapi/sound/asequencer.h
@@ -331,7 +331,7 @@ typedef int __bitwise snd_seq_client_type_t;
 #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_USE_EVENT	(1U<<31)	/* use event filter */
 
 struct snd_seq_client_info {
 	int client;			/* client number to inquire */
-- 
2.17.1

Re: [PATCH -next] ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT

Posted by Takashi Iwai 3 years, 4 months ago

On Mon, 21 Nov 2022 05:36:25 +0100,
Baisong Zhong wrote:
> 
> 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>
> ---
>  include/uapi/sound/asequencer.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/uapi/sound/asequencer.h b/include/uapi/sound/asequencer.h
> index 6d4a2c60808d..4c5c4dd15d02 100644
> --- a/include/uapi/sound/asequencer.h
> +++ b/include/uapi/sound/asequencer.h
> @@ -331,7 +331,7 @@ typedef int __bitwise snd_seq_client_type_t;
>  #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_USE_EVENT	(1U<<31)	/* use event filter */

Similarly like the previous patch for PCM, could you update all
SNDRV_SEQ_FILTER_* to 1U for consistency?


thanks,

Takashi

Re: [PATCH -next] ALSA: seq: fix undefined behavior in bit shift for SNDRV_SEQ_FILTER_USE_EVENT

Posted by zhongbaisong 3 years, 4 months ago


在 2022/11/21 18:35, Takashi Iwai 写道:
> On Mon, 21 Nov 2022 05:36:25 +0100,
> Baisong Zhong wrote:
>>
>> 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>
>> ---
>>   include/uapi/sound/asequencer.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/uapi/sound/asequencer.h b/include/uapi/sound/asequencer.h
>> index 6d4a2c60808d..4c5c4dd15d02 100644
>> --- a/include/uapi/sound/asequencer.h
>> +++ b/include/uapi/sound/asequencer.h
>> @@ -331,7 +331,7 @@ typedef int __bitwise snd_seq_client_type_t;
>>   #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_USE_EVENT	(1U<<31)	/* use event filter */
> 
> Similarly like the previous patch for PCM, could you update all
> SNDRV_SEQ_FILTER_* to 1U for consistency?
> 
> 
> thanks,
> 
> Takashi

Hi, Takashi
Thank you for your suggestion. I will update all
SNDRV_SEQ_FILTER_* to 1U for consistency in v2.

Baisong Zhong
.