From 65f2579916b6224c06514382d2bfc5841d43f291 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 5 Oct 2014 22:56:00 -0400 Subject: [PATCH] ext4: add ext4_iget_normal() which is to be used for dir tree lookups commit f4bb2981024fc91b23b4d09a8817c415396dbabb upstream. If there is a corrupted file system which has directory entries that point at reserved, metadata inodes, prohibit them from being used by treating them the same way we treat Boot Loader inodes --- that is, mark them to be bad inodes. This prohibits them from being opened, deleted, or modified via chmod, chown, utimes, etc. In particular, this prevents a corrupted file system which has a directory entry which points at the journal inode from being deleted and its blocks released, after which point Much Hilarity Ensues. Reported-by: Sami Liedes Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/ext4.h | 1 + fs/ext4/inode.c | 7 +++++++ fs/ext4/namei.c | 4 ++-- fs/ext4/super.c | 2 +- 4 files changed, 11 insertions(+), 3 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 790b14c5f262..3891475e22f7 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2088,6 +2088,7 @@ int do_journal_get_write_access(handle_t *handle, #define CONVERT_INLINE_DATA 2 extern struct inode *ext4_iget(struct super_block *, unsigned long); +extern struct inode *ext4_iget_normal(struct super_block *, unsigned long); extern int ext4_write_inode(struct inode *, struct writeback_control *); extern int ext4_setattr(struct dentry *, struct iattr *); extern int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f9e11df768d5..c04f7adc7b58 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4351,6 +4351,13 @@ bad_inode: return ERR_PTR(ret); } +struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino) +{ + if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) + return ERR_PTR(-EIO); + return ext4_iget(sb, ino); +} + static int ext4_inode_blocks_set(handle_t *handle, struct ext4_inode *raw_inode, struct ext4_inode_info *ei) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index ab2f6dc44b3a..f1312173fa90 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1430,7 +1430,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi dentry->d_name.name); return ERR_PTR(-EIO); } - inode = ext4_iget(dir->i_sb, ino); + inode = ext4_iget_normal(dir->i_sb, ino); if (inode == ERR_PTR(-ESTALE)) { EXT4_ERROR_INODE(dir, "deleted inode referenced: %u", @@ -1461,7 +1461,7 @@ struct dentry *ext4_get_parent(struct dentry *child) return ERR_PTR(-EIO); } - return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino)); + return d_obtain_alias(ext4_iget_normal(child->d_inode->i_sb, ino)); } /* diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 4a33907c3c8a..a1b780abdf18 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -964,7 +964,7 @@ static struct inode *ext4_nfs_get_inode(struct super_block *sb, * Currently we don't know the generation for parent directory, so * a generation of 0 means "accept any" */ - inode = ext4_iget(sb, ino); + inode = ext4_iget_normal(sb, ino); if (IS_ERR(inode)) return ERR_CAST(inode); if (generation && inode->i_generation != generation) { -- 2.20.1