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From c37e9e013469521d9adb932d17a1795c139b36db Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 17 Jun 2018 00:41:14 -0400
Subject: [PATCH] ext4: add more inode number paranoia checks
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.
Upstream-Status: Backport
https://bugzilla.kernel.org/show_bug.cgi?id=200069
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
---
fs/ext4/ext4.h | 5 -----
fs/ext4/inode.c | 3 ++-
fs/ext4/super.c | 5 +++++
3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 859d643..4bd6964 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1502,11 +1502,6 @@ static inline struct ext4_inode_info *EXT4_I(struct inode *inode)
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 c2f4ccb..7d6c100 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4506,7 +4506,8 @@ static int __ext4_get_inode_loc(struct inode *inode,
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 -EFSCORRUPTED;
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 4d34430..1f955c1 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3858,6 +3858,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
} 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)) {
--
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