[RFC PATCH 01/25] fs, fscrypt: move uapi definitions to new header <linux/fscrypt.h>

[Eric Biggers]

From: Eric Biggers <ebiggers at google.com>

There are going to be more filesystem encryption definitions added, and
we don't want to use a disproportionate amount of space in <linux/fs.h>
for filesystem encryption stuff.  So move the fscrypt definitions to a
new header <linux/fscrypt.h>.

For compatibility with existing userspace programs which may be
including <linux/fs.h>, <linux/fs.h> still includes the new header.
(It's debatable whether we really need this, though; the filesystem
encryption API is new enough that most if not all programs that are
using it have to declare it themselves anyway.)

Signed-off-by: Eric Biggers <ebiggers at google.com>
---
 include/linux/fscrypt.h      |  2 +-
 include/uapi/linux/fs.h      | 50 +++--------------------------------------
 include/uapi/linux/fscrypt.h | 53 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 48 deletions(-)
 create mode 100644 include/uapi/linux/fscrypt.h

diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 53437bfdfcbc..f7aa7d62e235 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -19,7 +19,7 @@
 #include <linux/bio.h>
 #include <linux/dcache.h>
 #include <crypto/skcipher.h>
-#include <uapi/linux/fs.h>
+#include <uapi/linux/fscrypt.h>
 
 #define FS_CRYPTO_BLOCK_SIZE		16
 
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 56235dddea7d..6ecd3ee9960c 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -12,6 +12,9 @@
 #include <linux/limits.h>
 #include <linux/ioctl.h>
 #include <linux/types.h>
+#ifndef __KERNEL__
+#include <linux/fscrypt.h>
+#endif
 
 /*
  * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
@@ -253,53 +256,6 @@ struct fsxattr {
 #define FS_IOC_FSGETXATTR		_IOR ('X', 31, struct fsxattr)
 #define FS_IOC_FSSETXATTR		_IOW ('X', 32, struct fsxattr)
 
-/*
- * File system encryption support
- */
-/* Policy provided via an ioctl on the topmost directory */
-#define FS_KEY_DESCRIPTOR_SIZE	8
-
-#define FS_POLICY_FLAGS_PAD_4		0x00
-#define FS_POLICY_FLAGS_PAD_8		0x01
-#define FS_POLICY_FLAGS_PAD_16		0x02
-#define FS_POLICY_FLAGS_PAD_32		0x03
-#define FS_POLICY_FLAGS_PAD_MASK	0x03
-#define FS_POLICY_FLAGS_VALID		0x03
-
-/* Encryption algorithms */
-#define FS_ENCRYPTION_MODE_INVALID		0
-#define FS_ENCRYPTION_MODE_AES_256_XTS		1
-#define FS_ENCRYPTION_MODE_AES_256_GCM		2
-#define FS_ENCRYPTION_MODE_AES_256_CBC		3
-#define FS_ENCRYPTION_MODE_AES_256_CTS		4
-#define FS_ENCRYPTION_MODE_AES_128_CBC		5
-#define FS_ENCRYPTION_MODE_AES_128_CTS		6
-
-struct fscrypt_policy {
-	__u8 version;
-	__u8 contents_encryption_mode;
-	__u8 filenames_encryption_mode;
-	__u8 flags;
-	__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
-};
-
-#define FS_IOC_SET_ENCRYPTION_POLICY	_IOR('f', 19, struct fscrypt_policy)
-#define FS_IOC_GET_ENCRYPTION_PWSALT	_IOW('f', 20, __u8[16])
-#define FS_IOC_GET_ENCRYPTION_POLICY	_IOW('f', 21, struct fscrypt_policy)
-
-/* Parameters for passing an encryption key into the kernel keyring */
-#define FS_KEY_DESC_PREFIX		"fscrypt:"
-#define FS_KEY_DESC_PREFIX_SIZE		8
-
-/* Structure that userspace passes to the kernel keyring */
-#define FS_MAX_KEY_SIZE			64
-
-struct fscrypt_key {
-	__u32 mode;
-	__u8 raw[FS_MAX_KEY_SIZE];
-	__u32 size;
-};
-
 /*
  * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
  *
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
new file mode 100644
index 000000000000..c09209fc42ea
--- /dev/null
+++ b/include/uapi/linux/fscrypt.h
@@ -0,0 +1,53 @@
+#ifndef _UAPI_LINUX_FSCRYPT_H
+#define _UAPI_LINUX_FSCRYPT_H
+
+#include <linux/types.h>
+
+/*
+ * File system encryption support
+ */
+/* Policy provided via an ioctl on the topmost directory */
+#define FS_KEY_DESCRIPTOR_SIZE	8
+
+#define FS_POLICY_FLAGS_PAD_4		0x00
+#define FS_POLICY_FLAGS_PAD_8		0x01
+#define FS_POLICY_FLAGS_PAD_16		0x02
+#define FS_POLICY_FLAGS_PAD_32		0x03
+#define FS_POLICY_FLAGS_PAD_MASK	0x03
+#define FS_POLICY_FLAGS_VALID		0x03
+
+/* Encryption algorithms */
+#define FS_ENCRYPTION_MODE_INVALID		0
+#define FS_ENCRYPTION_MODE_AES_256_XTS		1
+#define FS_ENCRYPTION_MODE_AES_256_GCM		2
+#define FS_ENCRYPTION_MODE_AES_256_CBC		3
+#define FS_ENCRYPTION_MODE_AES_256_CTS		4
+#define FS_ENCRYPTION_MODE_AES_128_CBC		5
+#define FS_ENCRYPTION_MODE_AES_128_CTS		6
+
+struct fscrypt_policy {
+	__u8 version;
+	__u8 contents_encryption_mode;
+	__u8 filenames_encryption_mode;
+	__u8 flags;
+	__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+};
+
+#define FS_IOC_SET_ENCRYPTION_POLICY	_IOR('f', 19, struct fscrypt_policy)
+#define FS_IOC_GET_ENCRYPTION_PWSALT	_IOW('f', 20, __u8[16])
+#define FS_IOC_GET_ENCRYPTION_POLICY	_IOW('f', 21, struct fscrypt_policy)
+
+/* Parameters for passing an encryption key into the kernel keyring */
+#define FS_KEY_DESC_PREFIX		"fscrypt:"
+#define FS_KEY_DESC_PREFIX_SIZE		8
+
+/* Structure that userspace passes to the kernel keyring */
+#define FS_MAX_KEY_SIZE			64
+
+struct fscrypt_key {
+	__u32 mode;
+	__u8 raw[FS_MAX_KEY_SIZE];
+	__u32 size;
+};
+
+#endif /* _UAPI_LINUX_FSCRYPT_H */
-- 
2.15.0.rc0.271.g36b669edcc-goog