Squashfs: add sanity checks to lookup table reading at mount time
Fsfuzzer generates corrupted filesystems which throw a warn_on in
kmalloc. One of these is due to a corrupted superblock inodes field.
Fix this by checking that the number of bytes to be read (and allocated)
does not extend into the next filesystem structure.
Also add a couple of other sanity checks of the mount-time lookup table
structures.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 8f5f278..80a7119 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -245,6 +245,7 @@
msblk->id_table = NULL;
goto failed_mount;
}
+ next_table = msblk->id_table[0];
/* Handle inode lookup table */
lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
@@ -253,7 +254,7 @@
/* Allocate and read inode lookup table */
msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
- lookup_table_start, msblk->inodes);
+ lookup_table_start, next_table, msblk->inodes);
if (IS_ERR(msblk->inode_lookup_table)) {
ERROR("unable to read inode lookup table\n");
err = PTR_ERR(msblk->inode_lookup_table);