diff mbox

[v2,2/5] fscrypt: fix renaming and linking special files

Message ID 1482186016-107643-2-git-send-email-ebiggers3@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Biggers Dec. 19, 2016, 10:20 p.m. UTC 
From: Eric Biggers <ebiggers@google.com>

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>
Cc: stable@vger.kernel.org
---
 fs/crypto/policy.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Theodore Ts'o Dec. 31, 2016, 5:49 a.m. UTC | #1 
On Mon, Dec 19, 2016 at 02:20:13PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> 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>
> Cc: stable@vger.kernel.org

Thanks, applied.

						- Ted
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diff mbox

Patch

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 5de0633..2e50cbc 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -198,6 +198,11 @@  int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
 	if (!cops->is_encrypted(parent))
 		return 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;
+
 	/* Encrypted directories must not contain unencrypted files */
 	if (!cops->is_encrypted(child))
 		return 0;