udf: Check length of extended attributes and allocation descriptors

commit 23b133bdc452aa441fcb9b82cbf6dd05cfd342d0 upstream.

Check length of extended attributes and allocation descriptors when
loading inodes from disk. Otherwise corrupted filesystems could confuse
the code and make the kernel oops.

Reported-by: Carl Henrik Lunde <chlunde@ping.uio.no>
Signed-off-by: Jan Kara <jack@suse.cz>
[lizf: Backported to 3.4:
 - call make_bad_inode() and then return
 - relace bs with inode->i_sb->s_blocksize]
Signed-off-by: Zefan Li <lizefan@huawei.com>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 8053ee75d297c2753c6c0d5cd7b843a7cd36c3be..330ec8cfeb630c0343d3e21f644e73cd86843b3b 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1392,6 +1392,19 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
                                                        iinfo->i_lenEAttr;
        }
 
+       /*
+        * Sanity check length of allocation descriptors and extended attrs to
+        * avoid integer overflows
+        */
+       if (iinfo->i_lenEAttr > inode->i_sb->s_blocksize || iinfo->i_lenAlloc > inode->i_sb->s_blocksize) {
+               make_bad_inode(inode);
+               return;
+       }
+       /* Now do exact checks */
+       if (udf_file_entry_alloc_offset(inode) + iinfo->i_lenAlloc > inode->i_sb->s_blocksize) {
+               make_bad_inode(inode);
+               return;
+       }
        /* Sanity checks for files in ICB so that we don't get confused later */
        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
                /*