From: Jaegeuk Kim Date: Tue, 21 Apr 2015 23:23:47 +0000 (-0700) Subject: f2fs crypto: add encryption key management facilities X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0adda907f23df2e19355b58a20f0a7ff76587c6a;p=linux-beck.git f2fs crypto: add encryption key management facilities This patch copies from encrypt_key.c in ext4, and modifies for f2fs. Use GFP_NOFS, since _f2fs_get_encryption_info is called under f2fs_lock_op. Signed-off-by: Michael Halcrow Signed-off-by: Ildar Muslukhov Signed-off-by: Theodore Ts'o Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile index a79907b4f9f5..b08925d34ed0 100644 --- a/fs/f2fs/Makefile +++ b/fs/f2fs/Makefile @@ -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 diff --git a/fs/f2fs/crypto_key.c b/fs/f2fs/crypto_key.c new file mode 100644 index 000000000000..c7d414dd3a4a --- /dev/null +++ b/fs/f2fs/crypto_key.c @@ -0,0 +1,206 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include + +#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); +} diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index b0490cb58b97..eb6440960964 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -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 diff --git a/fs/f2fs/f2fs_crypto.h b/fs/f2fs/f2fs_crypto.h index 3323266e7e2b..6e4139493ba5 100644 --- a/fs/f2fs/f2fs_crypto.h +++ b/fs/f2fs/f2fs_crypto.h @@ -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];