[PATCH 2/2] quota: Sanity-check quota file headers on load

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Perform basic sanity checks of quota headers to avoid kernel crashes on
corrupted quota files.

CC: stable@xxxxxxxxxxxxxxx
Reported-by: syzbot+f816042a7ae2225f25ba@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 fs/quota/quota_v2.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
index e69a2bfdd81c..c21106557a37 100644
--- a/fs/quota/quota_v2.c
+++ b/fs/quota/quota_v2.c
@@ -157,6 +157,25 @@ static int v2_read_file_info(struct super_block *sb, int type)
 		qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
 		qinfo->dqi_ops = &v2r1_qtree_ops;
 	}
+	ret = -EUCLEAN;
+	/* Some sanity checks of the read headers... */
+	if ((loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits >
+	    i_size_read(sb_dqopt(sb)->files[type])) {
+		quota_error(sb, "Number of blocks too big for quota file size (%llu > %llu).",
+		    (loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits,
+		    i_size_read(sb_dqopt(sb)->files[type]));
+		goto out;
+	}
+	if (qinfo->dqi_free_blk >= qinfo->dqi_blocks) {
+		quota_error(sb, "Free block number too big (%u >= %u).",
+			    qinfo->dqi_free_blk, qinfo->dqi_blocks);
+		goto out;
+	}
+	if (qinfo->dqi_free_entry >= qinfo->dqi_blocks) {
+		quota_error(sb, "Block with free entry too big (%u >= %u).",
+			    qinfo->dqi_free_entry, qinfo->dqi_blocks);
+		goto out;
+	}
 	ret = 0;
 out:
 	up_read(&dqopt->dqio_sem);
-- 
2.16.4




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux