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Commit a551d7c8 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

Merge branch 'fscrypt' into dev

parents 0cb80b48 6a34e4d2

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -5138,6 +5138,7 @@ F: include/linux/fscache*.h 
FS-CRYPTO: FILE SYSTEM LEVEL ENCRYPTION SUPPORT

M:	Theodore Y. Ts'o <tytso@mit.edu>

M:	Jaegeuk Kim <jaegeuk@kernel.org>

L:	linux-fsdevel@vger.kernel.org

S:	Supported

F:	fs/crypto/

F:	include/linux/fscrypto.h

fs/crypto/Kconfig

+0 −2
Original line number Diff line number Diff line
@@ -8,9 +8,7 @@ config FS_ENCRYPTION 
	select CRYPTO_XTS

	select CRYPTO_CTS

	select CRYPTO_CTR

	select CRYPTO_SHA256

	select KEYS

	select ENCRYPTED_KEYS

	help

	  Enable encryption of files and directories.  This

	  feature is similar to ecryptfs, but it is more memory

fs/crypto/crypto.c

+83 −55
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#include <linux/bio.h>

#include <linux/dcache.h>

#include <linux/namei.h>

#include <linux/fscrypto.h>

#include "fscrypt_private.h"



static unsigned int num_prealloc_crypto_pages = 32;

static unsigned int num_prealloc_crypto_ctxs = 128;
@@ -63,7 +63,7 @@ void fscrypt_release_ctx(struct fscrypt_ctx *ctx) 
{

	unsigned long flags;



	if (ctx->flags & FS_WRITE_PATH_FL && ctx->w.bounce_page) {

	if (ctx->flags & FS_CTX_HAS_BOUNCE_BUFFER_FL && ctx->w.bounce_page) {

		mempool_free(ctx->w.bounce_page, fscrypt_bounce_page_pool);

		ctx->w.bounce_page = NULL;

	}
@@ -121,7 +121,7 @@ struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode, gfp_t gfp_flags) 
	} else {

		ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL;

	}

	ctx->flags &= ~FS_WRITE_PATH_FL;

	ctx->flags &= ~FS_CTX_HAS_BOUNCE_BUFFER_FL;

	return ctx;

}

EXPORT_SYMBOL(fscrypt_get_ctx);
@@ -147,9 +147,9 @@ typedef enum { 
} fscrypt_direction_t;



static int do_page_crypto(const struct inode *inode,

			fscrypt_direction_t rw, pgoff_t index,

			fscrypt_direction_t rw, u64 lblk_num,

			struct page *src_page, struct page *dest_page,

			unsigned int src_len, unsigned int src_offset,

			unsigned int len, unsigned int offs,

			gfp_t gfp_flags)

{

	struct {
@@ -163,6 +163,8 @@ static int do_page_crypto(const struct inode *inode, 
	struct crypto_skcipher *tfm = ci->ci_ctfm;

	int res = 0;



	BUG_ON(len == 0);



	req = skcipher_request_alloc(tfm, gfp_flags);

	if (!req) {

		printk_ratelimited(KERN_ERR
@@ -176,14 +178,14 @@ static int do_page_crypto(const struct inode *inode, 
		page_crypt_complete, &ecr);



	BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE);

	xts_tweak.index = cpu_to_le64(index);

	xts_tweak.index = cpu_to_le64(lblk_num);

	memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));



	sg_init_table(&dst, 1);

	sg_set_page(&dst, dest_page, src_len, src_offset);

	sg_set_page(&dst, dest_page, len, offs);

	sg_init_table(&src, 1);

	sg_set_page(&src, src_page, src_len, src_offset);

	skcipher_request_set_crypt(req, &src, &dst, src_len, &xts_tweak);

	sg_set_page(&src, src_page, len, offs);

	skcipher_request_set_crypt(req, &src, &dst, len, &xts_tweak);

	if (rw == FS_DECRYPT)

		res = crypto_skcipher_decrypt(req);

	else
@@ -208,69 +210,87 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags) 
	ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);

	if (ctx->w.bounce_page == NULL)

		return ERR_PTR(-ENOMEM);

	ctx->flags |= FS_WRITE_PATH_FL;

	ctx->flags |= FS_CTX_HAS_BOUNCE_BUFFER_FL;

	return ctx->w.bounce_page;

}



/**

 * fscypt_encrypt_page() - Encrypts a page

 * @inode:     The inode for which the encryption should take place

 * @plaintext_page:   The page to encrypt. Must be locked.

 * @plaintext_len:    Length of plaintext within page

 * @plaintext_offset: Offset of plaintext within page

 * @index:            Index for encryption. This is mainly the page index, but

 *                    but might be different for multiple calls on same page.

 * @page:      The page to encrypt. Must be locked for bounce-page

 *             encryption.

 * @len:       Length of data to encrypt in @page and encrypted

 *             data in returned page.

 * @offs:      Offset of data within @page and returned

 *             page holding encrypted data.

 * @lblk_num:  Logical block number. This must be unique for multiple

 *             calls with same inode, except when overwriting

 *             previously written data.

 * @gfp_flags: The gfp flag for memory allocation

 *

 * Encrypts plaintext_page using the ctx encryption context. If

 * the filesystem supports it, encryption is performed in-place, otherwise a

 * new ciphertext_page is allocated and returned.

 * Encrypts @page using the ctx encryption context. Performs encryption

 * either in-place or into a newly allocated bounce page.

 * Called on the page write path.

 *

 * Called on the page write path.  The caller must call

 * Bounce page allocation is the default.

 * In this case, the contents of @page are encrypted and stored in an

 * allocated bounce page. @page has to be locked and the caller must call

 * fscrypt_restore_control_page() on the returned ciphertext page to

 * release the bounce buffer and the encryption context.

 *

 * Return: An allocated page with the encrypted content on success. Else, an

 * In-place encryption is used by setting the FS_CFLG_OWN_PAGES flag in

 * fscrypt_operations. Here, the input-page is returned with its content

 * encrypted.

 *

 * Return: A page with the encrypted content on success. Else, an

 * error value or NULL.

 */

struct page *fscrypt_encrypt_page(const struct inode *inode,

				struct page *plaintext_page,

				unsigned int plaintext_len,

				unsigned int plaintext_offset,

				pgoff_t index, gfp_t gfp_flags)

				struct page *page,

				unsigned int len,

				unsigned int offs,

				u64 lblk_num, gfp_t gfp_flags)



{

	struct fscrypt_ctx *ctx;

	struct page *ciphertext_page = plaintext_page;

	struct page *ciphertext_page = page;

	int err;



	BUG_ON(plaintext_len % FS_CRYPTO_BLOCK_SIZE != 0);

	BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0);



	if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {

		/* with inplace-encryption we just encrypt the page */

		err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,

					page, ciphertext_page,

					len, offs, gfp_flags);

		if (err)

			return ERR_PTR(err);



		return ciphertext_page;

	}



	BUG_ON(!PageLocked(page));



	ctx = fscrypt_get_ctx(inode, gfp_flags);

	if (IS_ERR(ctx))

		return (struct page *)ctx;



	if (!(inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION)) {

	/* The encryption operation will require a bounce page. */

	ciphertext_page = alloc_bounce_page(ctx, gfp_flags);

	if (IS_ERR(ciphertext_page))

		goto errout;

	}



	ctx->w.control_page = plaintext_page;

	err = do_page_crypto(inode, FS_ENCRYPT, index,

					plaintext_page, ciphertext_page,

					plaintext_len, plaintext_offset,

					gfp_flags);

	ctx->w.control_page = page;

	err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,

					page, ciphertext_page,

					len, offs, gfp_flags);

	if (err) {

		ciphertext_page = ERR_PTR(err);

		goto errout;

	}

	if (!(inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION)) {

	SetPagePrivate(ciphertext_page);

	set_page_private(ciphertext_page, (unsigned long)ctx);

	lock_page(ciphertext_page);

	}

	return ciphertext_page;



errout:
@@ -281,11 +301,12 @@ EXPORT_SYMBOL(fscrypt_encrypt_page); 


/**

 * fscrypt_decrypt_page() - Decrypts a page in-place

 * @inode: Encrypted inode to decrypt.

 * @page:  The page to decrypt. Must be locked.

 * @inode:     The corresponding inode for the page to decrypt.

 * @page:      The page to decrypt. Must be locked in case

 *             it is a writeback page (FS_CFLG_OWN_PAGES unset).

 * @len:       Number of bytes in @page to be decrypted.

 * @offs:      Start of data in @page.

 * @index: Index for encryption.

 * @lblk_num:  Logical block number.

 *

 * Decrypts page in-place using the ctx encryption context.

 *
@@ -294,10 +315,13 @@ EXPORT_SYMBOL(fscrypt_encrypt_page); 
 * Return: Zero on success, non-zero otherwise.

 */

int fscrypt_decrypt_page(const struct inode *inode, struct page *page,

			unsigned int len, unsigned int offs, pgoff_t index)

			unsigned int len, unsigned int offs, u64 lblk_num)

{

	return do_page_crypto(inode, FS_DECRYPT, page->index, page, page, len, offs,

			GFP_NOFS);

	if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))

		BUG_ON(!PageLocked(page));



	return do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page, len,

			offs, GFP_NOFS);

}

EXPORT_SYMBOL(fscrypt_decrypt_page);
@@ -501,17 +525,22 @@ static void fscrypt_destroy(void) 


/**

 * fscrypt_initialize() - allocate major buffers for fs encryption.

 * @cop_flags:  fscrypt operations flags

 *

 * We only call this when we start accessing encrypted files, since it

 * results in memory getting allocated that wouldn't otherwise be used.

 *

 * Return: Zero on success, non-zero otherwise.

 */

int fscrypt_initialize(void)

int fscrypt_initialize(unsigned int cop_flags)

{

	int i, res = -ENOMEM;



	if (fscrypt_bounce_page_pool)

	/*

	 * No need to allocate a bounce page pool if there already is one or

	 * this FS won't use it.

	 */

	if (cop_flags & FS_CFLG_OWN_PAGES || fscrypt_bounce_page_pool)

		return 0;



	mutex_lock(&fscrypt_init_mutex);
@@ -540,7 +569,6 @@ int fscrypt_initialize(void) 
	mutex_unlock(&fscrypt_init_mutex);

	return res;

}

EXPORT_SYMBOL(fscrypt_initialize);



/**

 * fscrypt_init() - Set up for fs encryption.

fs/crypto/fname.c

+2 −2
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ 


#include <linux/scatterlist.h>

#include <linux/ratelimit.h>

#include <linux/fscrypto.h>

#include "fscrypt_private.h"



/**

 * fname_crypt_complete() - completion callback for filename crypto
@@ -350,7 +350,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, 
		fname->disk_name.len = iname->len;

		return 0;

	}

	ret = get_crypt_info(dir);

	ret = fscrypt_get_crypt_info(dir);

	if (ret && ret != -EOPNOTSUPP)

		return ret;

fs/crypto/fscrypt_private.h

0 → 100644
+93 −0
Original line number Diff line number Diff line 
/*

 * fscrypt_private.h

 *

 * Copyright (C) 2015, Google, Inc.

 *

 * This contains encryption key functions.

 *

 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.

 */



#ifndef _FSCRYPT_PRIVATE_H

#define _FSCRYPT_PRIVATE_H



#include <linux/fscrypto.h>



#define FS_FNAME_CRYPTO_DIGEST_SIZE	32



/* Encryption parameters */

#define FS_XTS_TWEAK_SIZE		16

#define FS_AES_128_ECB_KEY_SIZE		16

#define FS_AES_256_GCM_KEY_SIZE		32

#define FS_AES_256_CBC_KEY_SIZE		32

#define FS_AES_256_CTS_KEY_SIZE		32

#define FS_AES_256_XTS_KEY_SIZE		64

#define FS_MAX_KEY_SIZE			64



#define FS_KEY_DESC_PREFIX		"fscrypt:"

#define FS_KEY_DESC_PREFIX_SIZE		8



#define FS_KEY_DERIVATION_NONCE_SIZE		16



/**

 * Encryption context for inode

 *

 * Protector format:

 *  1 byte: Protector format (1 = this version)

 *  1 byte: File contents encryption mode

 *  1 byte: File names encryption mode

 *  1 byte: Flags

 *  8 bytes: Master Key descriptor

 *  16 bytes: Encryption Key derivation nonce

 */

struct fscrypt_context {

	u8 format;

	u8 contents_encryption_mode;

	u8 filenames_encryption_mode;

	u8 flags;

	u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];

	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];

} __packed;



#define FS_ENCRYPTION_CONTEXT_FORMAT_V1		1



/* This is passed in from userspace into the kernel keyring */

struct fscrypt_key {

	u32 mode;

	u8 raw[FS_MAX_KEY_SIZE];

	u32 size;

} __packed;



/*

 * A pointer to this structure is stored in the file system's in-core

 * representation of an inode.

 */

struct fscrypt_info {

	u8 ci_data_mode;

	u8 ci_filename_mode;

	u8 ci_flags;

	struct crypto_skcipher *ci_ctfm;

	struct key *ci_keyring_key;

	u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];

};



#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL		0x00000001

#define FS_CTX_HAS_BOUNCE_BUFFER_FL		0x00000002



struct fscrypt_completion_result {

	struct completion completion;

	int res;

};



#define DECLARE_FS_COMPLETION_RESULT(ecr) \

	struct fscrypt_completion_result ecr = { \

		COMPLETION_INITIALIZER((ecr).completion), 0 }





/* crypto.c */

int fscrypt_initialize(unsigned int cop_flags);



/* keyinfo.c */

extern int fscrypt_get_crypt_info(struct inode *);



#endif /* _FSCRYPT_PRIVATE_H */