squashfs: fix potential buffer over-run on 4K block file systems

Sizing the buffer based on block size is incorrect, leading
to a potential buffer over-run on 4K block size file systems
(because the metadata block size is always 8K).  This bug
doesn't seem have triggered because 4K block size file systems
are not default, and also because metadata blocks after
compression tend to be less than 4K.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
This commit is contained in:
Phillip Lougher 2010-04-23 02:32:02 +01:00
parent 370ec3d1ed
commit e0d1f70010

View File

@ -87,9 +87,8 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
u64 cur_index = index >> msblk->devblksize_log2;
int bytes, compressed, b = 0, k = 0, page = 0, avail;
bh = kcalloc((msblk->block_size >> msblk->devblksize_log2) + 1,
sizeof(*bh), GFP_KERNEL);
bh = kcalloc(((srclength + msblk->devblksize - 1)
>> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL);
if (bh == NULL)
return -ENOMEM;