4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Biggers <[email protected]>

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 <[email protected]>
Reviewed-by: Richard Weinberger <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>


---
 fs/ext4/crypto_policy.c |    6 ++++++
 fs/f2fs/crypto_policy.c |    5 +++++
 2 files changed, 11 insertions(+)

--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -156,6 +156,12 @@ int ext4_is_child_context_consistent_wit
                WARN_ON(1);     /* Should never happen */
                return 0;
        }
+
+       /* 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 (!ext4_encrypted_inode(parent))
                return 1;
--- a/fs/f2fs/crypto_policy.c
+++ b/fs/f2fs/crypto_policy.c
@@ -149,6 +149,11 @@ int f2fs_is_child_context_consistent_wit
                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 (!f2fs_encrypted_inode(parent))
                return 1;


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