[PATCH 3.16 094/370] ext4: reject inodes with negative size

Ben Hutchings
2017-03-10T14:12:32Z

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit 7e6e1ef48fc02f3ac5d0edecbb0c6087cd758d58 upstream.

Don't load an inode with a negative size; this causes integer overflow
problems in the VFS.

[ Added EXT4_ERROR_INODE() to mark file system as corrupted. -TYT]

Fixes: a48380f769df (ext4: rename i_dir_acl to i_size_high)
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: use EIO instead of EFSCORRUPTED]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/ext4/inode.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4118,6 +4118,7 @@ struct inode *ext4_iget(struct super_blo
struct inode *inode;
journal_t *journal = EXT4_SB(sb)->s_journal;
long ret;
+ loff_t size;
int block;
uid_t i_uid;
gid_t i_gid;
@@ -4209,6 +4210,11 @@ struct inode *ext4_iget(struct super_blo
ei->i_file_acl |=
((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
inode->i_size = ext4_isize(raw_inode);
+ if ((size = i_size_read(inode)) < 0) {
+ EXT4_ERROR_INODE(inode, "bad i_size value: %lld", size);
+ ret = -EIO;
+ goto bad_inode;
+ }
ei->i_disksize = inode->i_size;
#ifdef CONFIG_QUOTA
ei->i_reserved_quota = 0;