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Date: Wed, 04 Feb 2009 03:07:48 +0000
From: Phillip Lougher <phillip@...gher.demon.co.uk>
To: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
akpm@...ux-foundation.org, snakebyte@....de, sliedes@...hut.fi
Cc: phillip@...gher.demon.co.uk
Subject: [PATCH] Squashfs: Fix oops when reading fsfuzzer corrupted filesystems
The following patch should fix a couple of reported oopses when mounting
fsfuzzer corrupted filesystems.
These oopses have been raised in this thread
http://marc.info/?l=linux-fsdevel&m=123212794425497&w=2
and on the kernel bug tracker
http://bugzilla.kernel.org/show_bug.cgi?id=12479
The patch is also available in the squashfs git tree here
git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus.git
Feedback to confirm they fix the reported oopses welcome.
Thanks
Phillip
From: Phillip Lougher <phillip@...gher.demon.co.uk>
Date: Wed, 4 Feb 2009 02:31:29 +0000
Subject: [PATCH] Squashfs: Fix oops when reading fsfuzzer corrupted filesystems
This fixes a code regression caused by the recent mainlining changes.
Zlib sometimes tries to output more data than expected when
decompressing corrupted data. The recent code changes call
zlib_inflate repeatedly, decompressing into separate 4K buffers, this
code didn't check for the possibility that zlib_inflate might ask
for too many buffers.
Signed-off-by: Phillip Lougher <phillip@...gher.demon.co.uk>
---
fs/squashfs/block.c | 12 ++++++++++--
fs/squashfs/cache.c | 4 ++--
fs/squashfs/squashfs.h | 2 +-
fs/squashfs/super.c | 2 +-
4 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index c837dfc..1edd836 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -80,7 +80,7 @@ static struct buffer_head *get_block_length(struct super_block *sb,
* generated a larger block - this does occasionally happen with zlib).
*/
int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
- int length, u64 *next_index, int srclength)
+ int length, u64 *next_index, int srclength, int pages)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
struct buffer_head **bh;
@@ -185,6 +185,14 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
}
if (msblk->stream.avail_out == 0) {
+ if (page == pages) {
+ ERROR("zlib_inflate tried to "
+ "decompress too much data, "
+ "expected %d bytes. Zlib "
+ "data probably corrupt\n",
+ srclength);
+ goto release_mutex;
+ }
msblk->stream.next_out = buffer[page++];
msblk->stream.avail_out = PAGE_CACHE_SIZE;
}
@@ -268,7 +276,7 @@ block_release:
put_bh(bh[k]);
read_failure:
- ERROR("sb_bread failed reading block 0x%llx\n", cur_index);
+ ERROR("squashfs_read_data failed to read block 0x%llx\n", index);
kfree(bh);
return -EIO;
}
diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c
index f29eda1..1c4739e 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -119,7 +119,7 @@ struct squashfs_cache_entry *squashfs_cache_get(struct super_block *sb,
entry->length = squashfs_read_data(sb, entry->data,
block, length, &entry->next_index,
- cache->block_size);
+ cache->block_size, cache->pages);
spin_lock(&cache->lock);
@@ -406,7 +406,7 @@ int squashfs_read_table(struct super_block *sb, void *buffer, u64 block,
for (i = 0; i < pages; i++, buffer += PAGE_CACHE_SIZE)
data[i] = buffer;
res = squashfs_read_data(sb, data, block, length |
- SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, length);
+ SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, length, pages);
kfree(data);
return res;
}
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 6b2515d..0e9feb6 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -34,7 +34,7 @@ static inline struct squashfs_inode_info *squashfs_i(struct inode *inode)
/* block.c */
extern int squashfs_read_data(struct super_block *, void **, u64, int, u64 *,
- int);
+ int, int);
/* cache.c */
extern struct squashfs_cache *squashfs_cache_init(char *, int, int);
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index a0466d7..f0d82a9 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -388,7 +388,7 @@ static int __init init_squashfs_fs(void)
return err;
}
- printk(KERN_INFO "squashfs: version 4.0 (2009/01/03) "
+ printk(KERN_INFO "squashfs: version 4.0 (2009/01/31) "
"Phillip Lougher\n");
return 0;
--
1.5.6.3
--
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