From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit 42d97eb0ade31e1bc537d086842f5d6e766d9d51 upstream. Please apply
to 4.4-stable; it is already in 4.9-stable. This is a backport of the
fix to fs/ext4/ and fs/f2fs/ for old kernels.
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@xxxxxxxxxx>
Reviewed-by: Richard Weinberger <richard@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
---
fs/ext4/crypto_policy.c | 6 ++++++
fs/f2fs/crypto_policy.c | 5 +++++
2 files changed, 11 insertions(+)
diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c
index 8a9feb341f31..dd561f916f0b 100644
--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -156,6 +156,12 @@ int ext4_is_child_context_consistent_with_parent(struct inode *parent,
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;
diff --git a/fs/f2fs/crypto_policy.c b/fs/f2fs/crypto_policy.c
index e504f548b64e..5bbd1989d5e6 100644
--- a/fs/f2fs/crypto_policy.c
+++ b/fs/f2fs/crypto_policy.c
@@ -149,6 +149,11 @@ int f2fs_is_child_context_consistent_with_parent(struct inode *parent,
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;
--
2.12.0.367.g23dc2f6d3c-goog