From 425dc465de3725210162da9b1e9062e86cc2de27 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 17 Jun 2018 00:41:14 -0400 Subject: [PATCH] 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 Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- 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 a8a750f..43e27d8 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1542,11 +1542,6 @@ static inline struct timespec ext4_current_time(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 81b16c3..5c4c9af 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4242,7 +4242,8 @@ 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 4c5d9df..25e078e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3713,6 +3713,11 @@ 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)) { -- 2.7.4