Squashfs: Fix oops when reading fsfuzzer corrupted filesystems
This fixes a code regression caused by the recent mainlining changes.
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 when decompressing corrupted
data.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index c837dfc..321728f 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -80,7 +80,7 @@
* 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 @@
}
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 +276,8 @@
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",
+ (unsigned long long) 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 @@
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 @@
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 @@
/* 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 071df5b..681ec0d 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -389,7 +389,7 @@
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;