From: Jan Kara jack@suse.cz
[ Upstream commit 781d2a9a2fc7d0be53a072794dc03ef6de770f3d ]
We were checking validity of LVID entries only when getting implementation use information from LVID in udf_sb_lvidiu(). However if the LVID is suitably corrupted, it can cause problems also to code such as udf_count_free() which doesn't use udf_sb_lvidiu(). So check validity of LVID already when loading it from the disk and just disable LVID altogether when it is not valid.
Reported-by: syzbot+7fbfe5fed73ebb675748@syzkaller.appspotmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- fs/udf/super.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/fs/udf/super.c b/fs/udf/super.c index c8c037e8e57b..cf2e770080f9 100644 --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -115,16 +115,10 @@ struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct super_block *sb) return NULL; lvid = (struct logicalVolIntegrityDesc *)UDF_SB(sb)->s_lvid_bh->b_data; partnum = le32_to_cpu(lvid->numOfPartitions); - if ((sb->s_blocksize - sizeof(struct logicalVolIntegrityDescImpUse) - - offsetof(struct logicalVolIntegrityDesc, impUse)) / - (2 * sizeof(uint32_t)) < partnum) { - udf_err(sb, "Logical volume integrity descriptor corrupted " - "(numOfPartitions = %u)!\n", partnum); - return NULL; - } /* The offset is to skip freeSpaceTable and sizeTable arrays */ offset = partnum * 2 * sizeof(uint32_t); - return (struct logicalVolIntegrityDescImpUse *)&(lvid->impUse[offset]); + return (struct logicalVolIntegrityDescImpUse *) + (((uint8_t *)(lvid + 1)) + offset); }
/* UDF filesystem type */ @@ -1571,6 +1565,7 @@ static void udf_load_logicalvolint(struct super_block *sb, struct kernel_extent_ struct udf_sb_info *sbi = UDF_SB(sb); struct logicalVolIntegrityDesc *lvid; int indirections = 0; + u32 parts, impuselen;
while (++indirections <= UDF_MAX_LVID_NESTING) { final_bh = NULL; @@ -1597,15 +1592,27 @@ static void udf_load_logicalvolint(struct super_block *sb, struct kernel_extent_
lvid = (struct logicalVolIntegrityDesc *)final_bh->b_data; if (lvid->nextIntegrityExt.extLength == 0) - return; + goto check;
loc = leea_to_cpu(lvid->nextIntegrityExt); }
udf_warn(sb, "Too many LVID indirections (max %u), ignoring.\n", UDF_MAX_LVID_NESTING); +out_err: brelse(sbi->s_lvid_bh); sbi->s_lvid_bh = NULL; + return; +check: + parts = le32_to_cpu(lvid->numOfPartitions); + impuselen = le32_to_cpu(lvid->lengthOfImpUse); + if (parts >= sb->s_blocksize || impuselen >= sb->s_blocksize || + sizeof(struct logicalVolIntegrityDesc) + impuselen + + 2 * parts * sizeof(u32) > sb->s_blocksize) { + udf_warn(sb, "Corrupted LVID (parts=%u, impuselen=%u), " + "ignoring.\n", parts, impuselen); + goto out_err; + } }