f2fs crypto: add encryption key management facilities (0adda907) · Commits · e / devices / android_kernel_oneplus_sm7250

fs/f2fs/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -6,4 +6,4 @@ f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
		f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
		f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
		f2fs-$(CONFIG_F2FS_IO_TRACE) += trace.o
		f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o crypto.o
		f2fs-$(CONFIG_F2FS_FS_ENCRYPTION) += crypto_policy.o crypto.o crypto_key.o

fs/f2fs/crypto_key.c

0 → 100644

+206 −0

Original line number	Diff line number	Diff line
		/*
		* linux/fs/f2fs/crypto_key.c
		*
		* Copied from linux/fs/f2fs/crypto_key.c
		*
		* Copyright (C) 2015, Google, Inc.
		*
		* This contains encryption key functions for f2fs
		*
		* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
		*/
		#include <keys/encrypted-type.h>
		#include <keys/user-type.h>
		#include <linux/random.h>
		#include <linux/scatterlist.h>
		#include <uapi/linux/keyctl.h>
		#include <crypto/hash.h>
		#include <linux/f2fs_fs.h>

		#include "f2fs.h"
		#include "xattr.h"

		static void derive_crypt_complete(struct crypto_async_request *req, int rc)
		{
		struct f2fs_completion_result *ecr = req->data;

		if (rc == -EINPROGRESS)
		return;

		ecr->res = rc;
		complete(&ecr->completion);
		}

		/**
		* f2fs_derive_key_aes() - Derive a key using AES-128-ECB
		* @deriving_key: Encryption key used for derivatio.
		* @source_key: Source key to which to apply derivation.
		* @derived_key: Derived key.
		*
		* Return: Zero on success; non-zero otherwise.
		*/
		static int f2fs_derive_key_aes(char deriving_key[F2FS_AES_128_ECB_KEY_SIZE],
		char source_key[F2FS_AES_256_XTS_KEY_SIZE],
		char derived_key[F2FS_AES_256_XTS_KEY_SIZE])
		{
		int res = 0;
		struct ablkcipher_request *req = NULL;
		DECLARE_F2FS_COMPLETION_RESULT(ecr);
		struct scatterlist src_sg, dst_sg;
		struct crypto_ablkcipher *tfm = crypto_alloc_ablkcipher("ecb(aes)", 0,
		0);

		if (IS_ERR(tfm)) {
		res = PTR_ERR(tfm);
		tfm = NULL;
		goto out;
		}
		crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
		req = ablkcipher_request_alloc(tfm, GFP_NOFS);
		if (!req) {
		res = -ENOMEM;
		goto out;
		}
		ablkcipher_request_set_callback(req,
		CRYPTO_TFM_REQ_MAY_BACKLOG \| CRYPTO_TFM_REQ_MAY_SLEEP,
		derive_crypt_complete, &ecr);
		res = crypto_ablkcipher_setkey(tfm, deriving_key,
		F2FS_AES_128_ECB_KEY_SIZE);
		if (res < 0)
		goto out;

		sg_init_one(&src_sg, source_key, F2FS_AES_256_XTS_KEY_SIZE);
		sg_init_one(&dst_sg, derived_key, F2FS_AES_256_XTS_KEY_SIZE);
		ablkcipher_request_set_crypt(req, &src_sg, &dst_sg,
		F2FS_AES_256_XTS_KEY_SIZE, NULL);
		res = crypto_ablkcipher_encrypt(req);
		if (res == -EINPROGRESS \|\| res == -EBUSY) {
		BUG_ON(req->base.data != &ecr);
		wait_for_completion(&ecr.completion);
		res = ecr.res;
		}
		out:
		if (req)
		ablkcipher_request_free(req);
		if (tfm)
		crypto_free_ablkcipher(tfm);
		return res;
		}

		void f2fs_free_encryption_info(struct inode *inode)
		{
		struct f2fs_inode_info *fi = F2FS_I(inode);
		struct f2fs_crypt_info *ci = fi->i_crypt_info;

		if (!ci)
		return;

		if (ci->ci_keyring_key)
		key_put(ci->ci_keyring_key);
		crypto_free_ablkcipher(ci->ci_ctfm);
		memzero_explicit(&ci->ci_raw, sizeof(ci->ci_raw));
		kfree(ci);
		fi->i_crypt_info = NULL;
		}

		int _f2fs_get_encryption_info(struct inode *inode)
		{
		struct f2fs_inode_info *fi = F2FS_I(inode);
		struct f2fs_crypt_info *crypt_info;
		char full_key_descriptor[F2FS_KEY_DESC_PREFIX_SIZE +
		(F2FS_KEY_DESCRIPTOR_SIZE * 2) + 1];
		struct key *keyring_key = NULL;
		struct f2fs_encryption_key *master_key;
		struct f2fs_encryption_context ctx;
		struct user_key_payload *ukp;
		int res;

		if (!f2fs_read_workqueue) {
		res = f2fs_init_crypto();
		if (res)
		return res;
		}

		if (fi->i_crypt_info) {
		if (!fi->i_crypt_info->ci_keyring_key \|\|
		key_validate(fi->i_crypt_info->ci_keyring_key) == 0)
		return 0;
		f2fs_free_encryption_info(inode);
		}

		res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_ENCRYPTION,
		F2FS_XATTR_NAME_ENCRYPTION_CONTEXT,
		&ctx, sizeof(ctx), NULL);
		if (res < 0)
		return res;
		else if (res != sizeof(ctx))
		return -EINVAL;
		res = 0;

		crypt_info = kmalloc(sizeof(struct f2fs_crypt_info), GFP_NOFS);
		if (!crypt_info)
		return -ENOMEM;

		crypt_info->ci_flags = ctx.flags;
		crypt_info->ci_data_mode = ctx.contents_encryption_mode;
		crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
		crypt_info->ci_ctfm = NULL;
		memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
		sizeof(crypt_info->ci_master_key));
		if (S_ISREG(inode->i_mode))
		crypt_info->ci_mode = ctx.contents_encryption_mode;
		else if (S_ISDIR(inode->i_mode) \|\| S_ISLNK(inode->i_mode))
		crypt_info->ci_mode = ctx.filenames_encryption_mode;
		else {
		printk(KERN_ERR "f2fs crypto: Unsupported inode type.\n");
		BUG();
		}
		crypt_info->ci_size = f2fs_encryption_key_size(crypt_info->ci_mode);
		BUG_ON(!crypt_info->ci_size);

		memcpy(full_key_descriptor, F2FS_KEY_DESC_PREFIX,
		F2FS_KEY_DESC_PREFIX_SIZE);
		sprintf(full_key_descriptor + F2FS_KEY_DESC_PREFIX_SIZE,
		"%*phN", F2FS_KEY_DESCRIPTOR_SIZE,
		ctx.master_key_descriptor);
		full_key_descriptor[F2FS_KEY_DESC_PREFIX_SIZE +
		(2 * F2FS_KEY_DESCRIPTOR_SIZE)] = '\0';
		keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
		if (IS_ERR(keyring_key)) {
		res = PTR_ERR(keyring_key);
		keyring_key = NULL;
		goto out;
		}
		BUG_ON(keyring_key->type != &key_type_logon);
		ukp = ((struct user_key_payload *)keyring_key->payload.data);
		if (ukp->datalen != sizeof(struct f2fs_encryption_key)) {
		res = -EINVAL;
		goto out;
		}
		master_key = (struct f2fs_encryption_key *)ukp->data;
		BUILD_BUG_ON(F2FS_AES_128_ECB_KEY_SIZE !=
		F2FS_KEY_DERIVATION_NONCE_SIZE);
		BUG_ON(master_key->size != F2FS_AES_256_XTS_KEY_SIZE);
		res = f2fs_derive_key_aes(ctx.nonce, master_key->raw,
		crypt_info->ci_raw);
		out:
		if (res < 0) {
		if (res == -ENOKEY)
		res = 0;
		kfree(crypt_info);
		} else {
		fi->i_crypt_info = crypt_info;
		crypt_info->ci_keyring_key = keyring_key;
		keyring_key = NULL;
		}
		if (keyring_key)
		key_put(keyring_key);
		return res;
		}

		int f2fs_has_encryption_key(struct inode *inode)
		{
		struct f2fs_inode_info *fi = F2FS_I(inode);

		return (fi->i_crypt_info != NULL);
		}

fs/f2fs/f2fs.h

+22 −0

Original line number	Diff line number	Diff line
		@@ -1974,17 +1974,39 @@ int f2fs_decrypt(struct f2fs_crypto_ctx , struct page );
		int f2fs_decrypt_one(struct inode , struct page );
		void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx , struct bio );

		/* crypto_key.c */
		void f2fs_free_encryption_info(struct inode *);
		int _f2fs_get_encryption_info(struct inode *inode);

		#ifdef CONFIG_F2FS_FS_ENCRYPTION
		void f2fs_restore_and_release_control_page(struct page **);
		void f2fs_restore_control_page(struct page *);

		int f2fs_init_crypto(void);
		void f2fs_exit_crypto(void);

		int f2fs_has_encryption_key(struct inode *);

		static inline int f2fs_get_encryption_info(struct inode *inode)
		{
		struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;

		if (!ci \|\|
		(ci->ci_keyring_key &&
		(ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) \|
		(1 << KEY_FLAG_REVOKED) \|
		(1 << KEY_FLAG_DEAD)))))
		return _f2fs_get_encryption_info(inode);
		return 0;
		}
		#else
		static inline void f2fs_restore_and_release_control_page(struct page **p) { }
		static inline void f2fs_restore_control_page(struct page *p) { }

		static inline int f2fs_init_crypto(void) { return 0; }
		static inline void f2fs_exit_crypto(void) { }

		static inline int f2fs_has_encryption_key(struct inode *i) { return 0; }
		static inline int f2fs_get_encryption_info(struct inode *i) { return 0; }
		#endif
		#endif

fs/f2fs/f2fs_crypto.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -65,6 +65,9 @@ struct f2fs_encryption_context {
		#define F2FS_AES_256_XTS_KEY_SIZE 64
		#define F2FS_MAX_KEY_SIZE 64

		#define F2FS_KEY_DESC_PREFIX "f2fs:"
		#define F2FS_KEY_DESC_PREFIX_SIZE 5

		struct f2fs_encryption_key {
		__u32 mode;
		char raw[F2FS_MAX_KEY_SIZE];