Commit dd01b690 authored Feb 01, 2017 by Eric Biggers Committed by Theodore Ts'o Feb 01, 2017

ext4: fix use-after-iput when fscrypt contexts are inconsistent



In the case where the child's encryption context was inconsistent with
its parent directory, we were using inode->i_sb and inode->i_ino after
the inode had already been iput().  Fix this by doing the iput() in the
correct places.

Note: only ext4 had this bug, not f2fs and ubifs.

Fixes: d9cdc903 ("ext4 crypto: enforce context consistency")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent dbfcef6b

fs/ext4/namei.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1618,13 +1618,15 @@ static struct dentry ext4_lookup(struct inode dir, struct dentry *dentry, unsi
		!fscrypt_has_permitted_context(dir, inode)) {
		int nokey = ext4_encrypted_inode(inode) &&
		!fscrypt_has_encryption_key(inode);
		if (nokey) {
		iput(inode);
		if (nokey)
		return ERR_PTR(-ENOKEY);
		}
		ext4_warning(inode->i_sb,
		"Inconsistent encryption contexts: %lu/%lu",
		(unsigned long) dir->i_ino,
		(unsigned long) inode->i_ino);
		iput(inode);
		return ERR_PTR(-EPERM);
		}
		}