ext4: add more inode number paranoia checks
commit c37e9e013469521d9adb932d17a1795c139b36db upstream.
If there is a directory entry pointing to a system inode (such as a
journal inode), complain and declare the file system to be corrupted.
Also, if the superblock's first inode number field is too small,
refuse to mount the file system.
This addresses CVE-2018-10882.
https://bugzilla.kernel.org/show_bug.cgi?id=200069
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 79f4ff3..def4d53 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1416,11 +1416,6 @@
static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
{
return ino == EXT4_ROOT_INO ||
- ino == EXT4_USR_QUOTA_INO ||
- ino == EXT4_GRP_QUOTA_INO ||
- ino == EXT4_BOOT_LOADER_INO ||
- ino == EXT4_JOURNAL_INO ||
- ino == EXT4_RESIZE_INO ||
(ino >= EXT4_FIRST_INO(sb) &&
ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
}
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 8a29fda..f9e8207 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3910,7 +3910,8 @@
int inodes_per_block, inode_offset;
iloc->bh = NULL;
- if (!ext4_valid_inum(sb, inode->i_ino))
+ if (inode->i_ino < EXT4_ROOT_INO ||
+ inode->i_ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
return -EIO;
iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 645d02e..ab32b5b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3796,6 +3796,11 @@
} else {
sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
+ if (sbi->s_first_ino < EXT4_GOOD_OLD_FIRST_INO) {
+ ext4_msg(sb, KERN_ERR, "invalid first ino: %u",
+ sbi->s_first_ino);
+ goto failed_mount;
+ }
if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
(!is_power_of_2(sbi->s_inode_size)) ||
(sbi->s_inode_size > blocksize)) {
