isofs: Fix unbounded recursion when processing relocated directories
We did not check relocated directory in any way when processing Rock
Ridge 'CL' tag. Thus a corrupted isofs image can possibly have a CL
entry pointing to another CL entry leading to possibly unbounded
recursion in kernel code and thus stack overflow or deadlocks (if there
is a loop created from CL entries).
Fix the problem by not allowing CL entry to point to a directory entry
with CL entry (such use makes no good sense anyway) and by checking
whether CL entry doesn't point to itself.
CC: stable@vger.kernel.org
Reported-by: Chris Evans <cevans@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/isofs/isofs.h b/fs/isofs/isofs.h
index 9916723..0ac4c1f 100644
--- a/fs/isofs/isofs.h
+++ b/fs/isofs/isofs.h
@@ -107,7 +107,7 @@
struct inode; /* To make gcc happy */
-extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *);
+extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *, int relocated);
extern int get_rock_ridge_filename(struct iso_directory_record *, char *, struct inode *);
extern int isofs_name_translate(struct iso_directory_record *, char *, struct inode *);
@@ -118,9 +118,24 @@
extern struct buffer_head *isofs_bread(struct inode *, sector_t);
extern int isofs_get_blocks(struct inode *, sector_t, struct buffer_head **, unsigned long);
-extern struct inode *isofs_iget(struct super_block *sb,
- unsigned long block,
- unsigned long offset);
+struct inode *__isofs_iget(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset,
+ int relocated);
+
+static inline struct inode *isofs_iget(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset)
+{
+ return __isofs_iget(sb, block, offset, 0);
+}
+
+static inline struct inode *isofs_iget_reloc(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset)
+{
+ return __isofs_iget(sb, block, offset, 1);
+}
/* Because the inode number is no longer relevant to finding the
* underlying meta-data for an inode, we are free to choose a more