diff options
| -rw-r--r-- | fs/udf/super.c | 45 |
1 files changed, 36 insertions, 9 deletions
diff --git a/fs/udf/super.c b/fs/udf/super.c index 9121938..3306b9f 100644 --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -76,6 +76,9 @@ #define UDF_DEFAULT_BLOCKSIZE 2048 +#define VSD_FIRST_SECTOR_OFFSET 32768 +#define VSD_MAX_SECTOR_OFFSET 0x800000 + enum { UDF_MAX_LINKS = 0xffff }; /* These are the "meat" - everything else is stuffing */ @@ -685,7 +688,7 @@ out_unlock: static loff_t udf_check_vsd(struct super_block *sb) { struct volStructDesc *vsd = NULL; - loff_t sector = 32768; + loff_t sector = VSD_FIRST_SECTOR_OFFSET; int sectorsize; struct buffer_head *bh = NULL; int nsr02 = 0; @@ -703,8 +706,18 @@ static loff_t udf_check_vsd(struct super_block *sb) udf_debug("Starting at sector %u (%ld byte sectors)\n", (unsigned int)(sector >> sb->s_blocksize_bits), sb->s_blocksize); - /* Process the sequence (if applicable) */ - for (; !nsr02 && !nsr03; sector += sectorsize) { + /* Process the sequence (if applicable). The hard limit on the sector + * offset is arbitrary, hopefully large enough so that all valid UDF + * filesystems will be recognised. There is no mention of an upper + * bound to the size of the volume recognition area in the standard. + * The limit will prevent the code to read all the sectors of a + * specially crafted image (like a bluray disc full of CD001 sectors), + * potentially causing minutes or even hours of uninterruptible I/O + * activity. This actually happened with uninitialised SSD partitions + * (all 0xFF) before the check for the limit and all valid IDs were + * added */ + for (; !nsr02 && !nsr03 && sector < VSD_MAX_SECTOR_OFFSET; + sector += sectorsize) { /* Read a block */ bh = udf_tread(sb, sector >> sb->s_blocksize_bits); if (!bh) @@ -714,10 +727,7 @@ static loff_t udf_check_vsd(struct super_block *sb) vsd = (struct volStructDesc *)(bh->b_data + (sector & (sb->s_blocksize - 1))); - if (vsd->stdIdent[0] == 0) { - brelse(bh); - break; - } else if (!strncmp(vsd->stdIdent, VSD_STD_ID_CD001, + if (!strncmp(vsd->stdIdent, VSD_STD_ID_CD001, VSD_STD_ID_LEN)) { switch (vsd->structType) { case 0: @@ -753,6 +763,17 @@ static loff_t udf_check_vsd(struct super_block *sb) else if (!strncmp(vsd->stdIdent, VSD_STD_ID_NSR03, VSD_STD_ID_LEN)) nsr03 = sector; + else if (!strncmp(vsd->stdIdent, VSD_STD_ID_BOOT2, + VSD_STD_ID_LEN)) + ; /* nothing */ + else if (!strncmp(vsd->stdIdent, VSD_STD_ID_CDW02, + VSD_STD_ID_LEN)) + ; /* nothing */ + else { + /* invalid id : end of volume recognition area */ + brelse(bh); + break; + } brelse(bh); } @@ -760,7 +781,8 @@ static loff_t udf_check_vsd(struct super_block *sb) return nsr03; else if (nsr02) return nsr02; - else if (sector - (sbi->s_session << sb->s_blocksize_bits) == 32768) + else if (!bh && sector - (sbi->s_session << sb->s_blocksize_bits) == + VSD_FIRST_SECTOR_OFFSET) return -1; else return 0; @@ -1270,6 +1292,9 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block) * PHYSICAL partitions are already set up */ type1_idx = i; +#ifdef UDFFS_DEBUG + map = NULL; /* supress 'maybe used uninitialized' warning */ +#endif for (i = 0; i < sbi->s_partitions; i++) { map = &sbi->s_partmaps[i]; @@ -1891,7 +1916,9 @@ static int udf_load_vrs(struct super_block *sb, struct udf_options *uopt, return 0; } if (nsr_off == -1) - udf_debug("Failed to read byte 32768. Assuming open disc. Skipping validity check\n"); + udf_debug("Failed to read sector at offset %d. " + "Assuming open disc. Skipping validity " + "check\n", VSD_FIRST_SECTOR_OFFSET); if (!sbi->s_last_block) sbi->s_last_block = udf_get_last_block(sb); } else { |
