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| author | Vegard Nossum <vegard.nossum@oracle.com> | 2015-12-10 19:13:41 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2015-12-14 22:13:36 +0300 |
| commit | e7a4eb861203b605c6428ec29e0b5e3c3f4f537f (patch) | |
| tree | 0ce3fe22c7c0013f7ba9b7b9308bfb2f91cb4dc1 /fs/udf | |
| parent | 331221fac721788615dd9d5b27f710f7c758d60a (diff) | |
| download | linux-e7a4eb861203b605c6428ec29e0b5e3c3f4f537f.tar.xz | |
udf: limit the maximum number of TD redirections
Filesystem fuzzing revealed that we could get stuck in the
udf_process_sequence() loop.
The maximum limit was chosen arbitrarily but fixes the problem I saw.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/udf')
| -rw-r--r-- | fs/udf/super.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/udf/super.c b/fs/udf/super.c index 81155b9b445b..fd45537eaa01 100644 --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -1586,6 +1586,13 @@ static void udf_load_logicalvolint(struct super_block *sb, struct kernel_extent_ } /* + * Maximum number of Terminating Descriptor redirections. The chosen number is + * arbitrary - just that we hopefully don't limit any real use of rewritten + * inode on write-once media but avoid looping for too long on corrupted media. + */ +#define UDF_MAX_TD_NESTING 64 + +/* * Process a main/reserve volume descriptor sequence. * @block First block of first extent of the sequence. * @lastblock Lastblock of first extent of the sequence. @@ -1609,6 +1616,7 @@ static noinline int udf_process_sequence( uint16_t ident; long next_s = 0, next_e = 0; int ret; + unsigned int indirections = 0; memset(vds, 0, sizeof(struct udf_vds_record) * VDS_POS_LENGTH); @@ -1679,6 +1687,12 @@ static noinline int udf_process_sequence( } break; case TAG_IDENT_TD: /* ISO 13346 3/10.9 */ + if (++indirections > UDF_MAX_TD_NESTING) { + udf_err(sb, "too many TDs (max %u supported)\n", UDF_MAX_TD_NESTING); + brelse(bh); + return -EIO; + } + vds[VDS_POS_TERMINATING_DESC].block = block; if (next_e) { block = next_s; |