Patch "fscrypt: fix renaming and linking special files" has been added to the 4.9-stable tree

Patch "fscrypt: fix renaming and linking special files" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    fscrypt: fix renaming and linking special files

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fscrypt-fix-renaming-and-linking-special-files.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 42d97eb0ade31e1bc537d086842f5d6e766d9d51 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Mon, 19 Dec 2016 14:20:13 -0800
Subject: fscrypt: fix renaming and linking special files

From: Eric Biggers <ebiggers@google.com>

commit 42d97eb0ade31e1bc537d086842f5d6e766d9d51 upstream.

Attempting to link a device node, named pipe, or socket file into an
encrypted directory through rename(2) or link(2) always failed with
EPERM.  This happened because fscrypt_has_permitted_context() saw that
the file was unencrypted and forbid creating the link.  This behavior
was unexpected because such files are never encrypted; only regular
files, directories, and symlinks can be encrypted.

To fix this, make fscrypt_has_permitted_context() always return true on
special files.

This will be covered by a test in my encryption xfstests patchset.

Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/crypto/policy.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -171,6 +171,11 @@ int fscrypt_has_permitted_context(struct
 		BUG_ON(1);
 	}
 
+	/* No restrictions on file types which are never encrypted */
+	if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
+	    !S_ISLNK(child->i_mode))
+		return 1;
+
 	/* no restrictions if the parent directory is not encrypted */
 	if (!parent->i_sb->s_cop->is_encrypted(parent))
 		return 1;


Patches currently in stable-queue which might be from ebiggers@google.com are

queue-4.9/fscrypt-fix-renaming-and-linking-special-files.patch