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| author | Vegard Nossum <vegard.nossum@oracle.com> | 2015-12-11 15:54:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-25 11:57:48 -0800 |
| commit | 6b3a508f58f55ce1271c422d71e07f94f6ce7de5 (patch) | |
| tree | d77ee288e63b1e7a680d6eb56b0fe541b021c70b | |
| parent | 45a74b1ce8a11efc82d49100648f7c5dc753cbb8 (diff) | |
| download | lwn-6b3a508f58f55ce1271c422d71e07f94f6ce7de5.tar.gz lwn-6b3a508f58f55ce1271c422d71e07f94f6ce7de5.zip | |
udf: limit the maximum number of indirect extents in a row
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.nossum@oracle.com>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/udf/inode.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 789814f27438..5c1120a5fa42 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -2055,14 +2055,29 @@ 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); |