diff mbox

[4/4] ubifs: check for consistent encryption contexts in ubifs_lookup()

Message ID 20170407175840.95740-5-ebiggers3@gmail.com (mailing list archive)
State Accepted
Headers show

Commit Message

Eric Biggers April 7, 2017, 5:58 p.m. UTC 
From: Eric Biggers <ebiggers@google.com>

As ext4 and f2fs do, ubifs should check for consistent encryption
contexts during ->lookup() in an encrypted directory.  This protects
certain users of filesystem encryption against certain types of offline
attacks.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/ubifs/dir.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Theodore Ts'o April 30, 2017, 6:18 a.m. UTC | #1 
On Fri, Apr 07, 2017 at 10:58:40AM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> As ext4 and f2fs do, ubifs should check for consistent encryption
> contexts during ->lookup() in an encrypted directory.  This protects
> certain users of filesystem encryption against certain types of offline
> attacks.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

Thanks, applied.

						- Ted
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diff mbox

Patch

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 30825d882aa9..bbe2b346a94f 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -285,6 +285,15 @@  static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
 		goto out_dent;
 	}
 
+	if (ubifs_crypt_is_encrypted(dir) &&
+	    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
+	    !fscrypt_has_permitted_context(dir, inode)) {
+		ubifs_warn(c, "Inconsistent encryption contexts: %lu/%lu",
+			   dir->i_ino, inode->i_ino);
+		err = -EPERM;
+		goto out_inode;
+	}
+
 done:
 	kfree(dent);
 	fscrypt_free_filename(&nm);
@@ -295,6 +304,8 @@  static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
 	d_add(dentry, inode);
 	return NULL;
 
+out_inode:
+	iput(inode);
 out_dent:
 	kfree(dent);
 out_fname: