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authorPhillip Lougher <phillip@lougher.demon.co.uk>2011-03-15 22:09:55 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 16:53:11 -0700
commit6f5ff91733db188b0cbcc59482dbc7e20b17d56d (patch)
tree7f65f8d6782c98bffe29e2ba7b8539ec91216f08
parent98eec152c36e9544a81fa709d0eb2cf028cf4cdb (diff)
downloadlinux-linaro-stable-6f5ff91733db188b0cbcc59482dbc7e20b17d56d.tar.gz
Squashfs: handle corruption of directory structure
commit 44cff8a9ee8a974f9e931df910688e7fc1f0b0f9 upstream. Handle the rare case where a directory metadata block is uncompressed and corrupted, leading to a kernel oops in directory scanning (memcpy). Normally corruption is detected at the decompression stage and dealt with then, however, this will not happen if: - metadata isn't compressed (users can optionally request no metadata compression), or - the compressed metadata block was larger than the original, in which case the uncompressed version was used, or - the data was corrupt after decompression This patch fixes this by adding some sanity checks against known maximum values. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/squashfs/dir.c9
-rw-r--r--fs/squashfs/namei.c12
2 files changed, 21 insertions, 0 deletions
diff --git a/fs/squashfs/dir.c b/fs/squashfs/dir.c
index 566b0eaed868..16c1b4a533b2 100644
--- a/fs/squashfs/dir.c
+++ b/fs/squashfs/dir.c
@@ -173,6 +173,11 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
length += sizeof(dirh);
dir_count = le32_to_cpu(dirh.count) + 1;
+
+ /* dir_count should never be larger than 256 */
+ if (dir_count > 256)
+ goto failed_read;
+
while (dir_count--) {
/*
* Read directory entry.
@@ -184,6 +189,10 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
size = le16_to_cpu(dire->size) + 1;
+ /* size should never be larger than SQUASHFS_NAME_LEN */
+ if (size > SQUASHFS_NAME_LEN)
+ goto failed_read;
+
err = squashfs_read_metadata(inode->i_sb, dire->name,
&block, &offset, size);
if (err < 0)
diff --git a/fs/squashfs/namei.c b/fs/squashfs/namei.c
index 9e398653b22b..ac527512f073 100644
--- a/fs/squashfs/namei.c
+++ b/fs/squashfs/namei.c
@@ -175,6 +175,11 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
length += sizeof(dirh);
dir_count = le32_to_cpu(dirh.count) + 1;
+
+ /* dir_count should never be larger than 256 */
+ if (dir_count > 256)
+ goto data_error;
+
while (dir_count--) {
/*
* Read directory entry.
@@ -186,6 +191,10 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
size = le16_to_cpu(dire->size) + 1;
+ /* size should never be larger than SQUASHFS_NAME_LEN */
+ if (size > SQUASHFS_NAME_LEN)
+ goto data_error;
+
err = squashfs_read_metadata(dir->i_sb, dire->name,
&block, &offset, size);
if (err < 0)
@@ -227,6 +236,9 @@ exit_lookup:
d_add(dentry, inode);
return ERR_PTR(0);
+data_error:
+ err = -EIO;
+
read_failure:
ERROR("Unable to read directory block [%llx:%x]\n",
squashfs_i(dir)->start + msblk->directory_table,