[PATCH] squashfs: Fix sqfs_inode_size() for xattr related SQFS_LSYMLINK_TYPE

[nvbolhuis at gmail.com]

From: Norbert van Bolhuis <nvbolhuis at gmail.com>

A squashfs filesystem with extended attributes (xattrs) may have
inodes of type SQFS_LSYMLINK_TYPE. This might cause u-boot to fail to
handle the filesystem since it assumes a SYMLINK_TYPE and LSYMLINK_TYPE
inode are the same size. This is wrong, see:
https://github.com/plougher/squashfs-tools/blob/master/squashfs-tools/read_fs.c#L421

Using the mksquashfs '-no-xattrs' argument is probably best, but the
mksquashfs '-xattrs' argument is the default.
This patch fixes squashfs image handling by making sure parsing the
uncompressed inode_table (with sqfs_find_inode) succeeeds. The only change
needed is correctly determining the size of a SQFS_LSYMLINK_TYPE inode.

Signed-off-by: Norbert van Bolhuis <nvbolhuis at gmail.com>
---
 fs/squashfs/sqfs_inode.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/squashfs/sqfs_inode.c b/fs/squashfs/sqfs_inode.c
index bb3ccd37e3..ce9a8ff8e2 100644
--- a/fs/squashfs/sqfs_inode.c
+++ b/fs/squashfs/sqfs_inode.c
@@ -19,7 +19,9 @@
 
 int sqfs_inode_size(struct squashfs_base_inode *inode, u32 blk_size)
 {
-	switch (get_unaligned_le16(&inode->inode_type)) {
+	u16 inode_type = get_unaligned_le16(&inode->inode_type);
+
+	switch (inode_type) {
 	case SQFS_DIR_TYPE:
 		return sizeof(struct squashfs_dir_inode);
 
@@ -87,7 +89,7 @@ int sqfs_inode_size(struct squashfs_base_inode *inode, u32 blk_size)
 		    get_unaligned_le32(&symlink->symlink_size), &size))
 			return -EINVAL;
 
-		return size;
+		return (inode_type == SQFS_SYMLINK_TYPE) ? size : size + sizeof(u32);
 	}
 
 	case SQFS_BLKDEV_TYPE:
-- 
2.47.1