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ALSA: mixart: range checking proc file 

The original code doesn't take into consideration that the value of
MIXART_BA0_SIZE - pos can be less than zero which would lead to a large
unsigned value for "count".

Also I moved the check that read size is a multiple of 4 bytes below
the code that adjusts "count".

Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: <stable@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Dan Carpenter 2010-04-06 19:31:26 +03:00 committed by Takashi Iwai
parent a0fd4345f9
commit b0cc58a25d
1 changed files with 14 additions and 10 deletions
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24
sound/pci/mixart/mixart.c
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@ -1161,13 +1161,15 @@ static long snd_mixart_BA0_read(struct snd_info_entry *entry, void *file_private
unsigned long count, unsigned long pos)
{
struct mixart_mgr *mgr = entry->private_data;
unsigned long maxsize;
count = count & ~3; /* make sure the read size is a multiple of 4 bytes */
if(count <= 0)
if (pos >= MIXART_BA0_SIZE)
return 0;
if(pos + count > MIXART_BA0_SIZE)
count = (long)(MIXART_BA0_SIZE - pos);
if(copy_to_user_fromio(buf, MIXART_MEM( mgr, pos ), count))
maxsize = MIXART_BA0_SIZE - pos;
if (count > maxsize)
count = maxsize;
count = count & ~3; /* make sure the read size is a multiple of 4 bytes */
if (copy_to_user_fromio(buf, MIXART_MEM(mgr, pos), count))
return -EFAULT;
return count;
}
@ -1180,13 +1182,15 @@ static long snd_mixart_BA1_read(struct snd_info_entry *entry, void *file_private
unsigned long count, unsigned long pos)
{
struct mixart_mgr *mgr = entry->private_data;
unsigned long maxsize;
count = count & ~3; /* make sure the read size is a multiple of 4 bytes */
if(count <= 0)
if (pos > MIXART_BA1_SIZE)
return 0;
if(pos + count > MIXART_BA1_SIZE)
count = (long)(MIXART_BA1_SIZE - pos);
if(copy_to_user_fromio(buf, MIXART_REG( mgr, pos ), count))
maxsize = MIXART_BA1_SIZE - pos;
if (count > maxsize)
count = maxsize;
count = count & ~3; /* make sure the read size is a multiple of 4 bytes */
if (copy_to_user_fromio(buf, MIXART_REG(mgr, pos), count))
return -EFAULT;
return count;
}