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Commit ff978b09 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4 crypto: move context consistency check to ext4_file_open() 



In the case where the per-file key for the directory is cached, but
root does not have access to the key needed to derive the per-file key
for the files in the directory, we allow the lookup to succeed, so
that lstat(2) and unlink(2) can suceed.  However, if a program tries
to open the file, it will get an ENOKEY error.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 28b4c263

fs/ext4/file.c

+9 −0
Original line number Diff line number Diff line
@@ -350,6 +350,7 @@ static int ext4_file_open(struct inode * inode, struct file * filp) 
	struct super_block *sb = inode->i_sb;

	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

	struct vfsmount *mnt = filp->f_path.mnt;

	struct inode *dir = filp->f_path.dentry->d_parent->d_inode;

	struct path path;

	char buf[64], *cp;

	int ret;
@@ -393,6 +394,14 @@ static int ext4_file_open(struct inode * inode, struct file * filp) 
		if (ext4_encryption_info(inode) == NULL)

			return -ENOKEY;

	}

	if (ext4_encrypted_inode(dir) &&

	    !ext4_is_child_context_consistent_with_parent(dir, inode)) {

		ext4_warning(inode->i_sb,

			     "Inconsistent encryption contexts: %lu/%lu\n",

			     (unsigned long) dir->i_ino,

			     (unsigned long) inode->i_ino);

		return -EPERM;

	}

	/*

	 * Set up the jbd2_inode if we are opening the inode for

	 * writing and the journal is present

fs/ext4/namei.c

+6 −2
Original line number Diff line number Diff line
@@ -1603,11 +1603,15 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi 
			return ERR_PTR(-EFSCORRUPTED);

		}

		if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&

		    (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||

		     S_ISLNK(inode->i_mode)) &&

		    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&

		    !ext4_is_child_context_consistent_with_parent(dir,

								  inode)) {

			int nokey = ext4_encrypted_inode(inode) &&

				!ext4_encryption_info(inode);



			iput(inode);

			if (nokey)

				return ERR_PTR(-ENOKEY);

			ext4_warning(inode->i_sb,

				     "Inconsistent encryption contexts: %lu/%lu\n",

				     (unsigned long) dir->i_ino,