2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Vegard Nossum <vegard.nos...@oracle.com>
commit b0918d9f476a8434b055e362b83fa4fd1d462c3f upstream.
udf_next_aext() just follows extent pointers while extents are marked as
indirect. This can loop forever for corrupted filesystem. Limit number
the of indirect extents we are willing to follow in a row.
[JK: Updated changelog, limit, style]
Signed-off-by: Vegard Nossum <vegard.nos...@oracle.com>
Cc: Jan Kara <j...@suse.com>
Cc: Quentin Casasnovas <quentin.casasno...@oracle.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Jan Kara <j...@suse.cz>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
[wt: udf_error() instead of udf_err() in 2.6.32]
Signed-off-by: Willy Tarreau <w...@1wt.eu>
---
fs/udf/inode.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index b8d7a0e..a22f568 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1869,14 +1869,29 @@ int8_t udf_write_aext(struct inode *inode, struct
extent_position *epos,
return (elen >> 30);
}
+/*
+ * Only 1 indirect extent in a row really makes sense but allow upto 16 in case
+ * someone does some weird stuff.
+ */
+#define UDF_MAX_INDIR_EXTS 16
+
int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
struct kernel_lb_addr *eloc, uint32_t *elen, int inc)
{
int8_t etype;
+ unsigned int indirections = 0;
while ((etype = udf_current_aext(inode, epos, eloc, elen, inc)) ==
(EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
int block;
+
+ if (++indirections > UDF_MAX_INDIR_EXTS) {
+ udf_error(inode->i_sb, __func__,
+ "too many indirect extents in inode %lu\n",
+ inode->i_ino);
+ return -1;
+ }
+
epos->block = *eloc;
epos->offset = sizeof(struct allocExtDesc);
brelse(epos->bh);
--
1.7.12.2.21.g234cd45.dirty
