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authorVegard Nossum <vegard.nossum@oracle.com>2015-12-11 17:54:16 +0300
committerJan Kara <jack@suse.cz>2015-12-23 13:47:55 +0300
commitb0918d9f476a8434b055e362b83fa4fd1d462c3f (patch)
tree8dfe5525ec62da377c446d8ebdb92d829089bbf7 /fs/udf
parente7a4eb861203b605c6428ec29e0b5e3c3f4f537f (diff)
downloadlinux-b0918d9f476a8434b055e362b83fa4fd1d462c3f.tar.xz
udf: limit the maximum number of indirect extents in a row
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.nossum@oracle.com> Cc: stable@vger.kernel.org Cc: Jan Kara <jack@suse.com> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/udf')
-rw-r--r--fs/udf/inode.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 8d0b3ade0ff0..566df9b5a6cb 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -2047,14 +2047,29 @@ void udf_write_aext(struct inode *inode, struct extent_position *epos,
epos->offset += adsize;
}
+/*
+ * 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_err(inode->i_sb,
+ "too many indirect extents in inode %lu\n",
+ inode->i_ino);
+ return -1;
+ }
+
epos->block = *eloc;
epos->offset = sizeof(struct allocExtDesc);
brelse(epos->bh);