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author | Eric Biggers <ebiggers@google.com> | 2019-08-04 19:35:45 -0700 |
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committer | Eric Biggers <ebiggers@google.com> | 2019-08-12 19:06:06 -0700 |
commit | feed825861919ac3fac4b2ab83673dd5225f7f0d (patch) | |
tree | 847366a45149de2bd984b0b3bc4c44ced1c3e838 /fs/crypto/keyinfo.c | |
parent | fscrypt: move v1 policy key setup to keysetup_v1.c (diff) | |
download | linux-dev-feed825861919ac3fac4b2ab83673dd5225f7f0d.tar.xz linux-dev-feed825861919ac3fac4b2ab83673dd5225f7f0d.zip |
fscrypt: rename keyinfo.c to keysetup.c
Rename keyinfo.c to keysetup.c since this better describes what the file
does (sets up the key), and it matches the new file keysetup_v1.c.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'fs/crypto/keyinfo.c')
-rw-r--r-- | fs/crypto/keyinfo.c | 345 |
1 files changed, 0 insertions, 345 deletions
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c deleted file mode 100644 index f4a47448e9ef..000000000000 --- a/fs/crypto/keyinfo.c +++ /dev/null @@ -1,345 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Key setup facility for FS encryption support. - * - * Copyright (C) 2015, Google, Inc. - * - * Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar. - * Heavily modified since then. - */ - -#include <crypto/aes.h> -#include <crypto/sha.h> -#include <crypto/skcipher.h> -#include <linux/key.h> - -#include "fscrypt_private.h" - -static struct crypto_shash *essiv_hash_tfm; - -static struct fscrypt_mode available_modes[] = { - [FSCRYPT_MODE_AES_256_XTS] = { - .friendly_name = "AES-256-XTS", - .cipher_str = "xts(aes)", - .keysize = 64, - .ivsize = 16, - }, - [FSCRYPT_MODE_AES_256_CTS] = { - .friendly_name = "AES-256-CTS-CBC", - .cipher_str = "cts(cbc(aes))", - .keysize = 32, - .ivsize = 16, - }, - [FSCRYPT_MODE_AES_128_CBC] = { - .friendly_name = "AES-128-CBC", - .cipher_str = "cbc(aes)", - .keysize = 16, - .ivsize = 16, - .needs_essiv = true, - }, - [FSCRYPT_MODE_AES_128_CTS] = { - .friendly_name = "AES-128-CTS-CBC", - .cipher_str = "cts(cbc(aes))", - .keysize = 16, - .ivsize = 16, - }, - [FSCRYPT_MODE_ADIANTUM] = { - .friendly_name = "Adiantum", - .cipher_str = "adiantum(xchacha12,aes)", - .keysize = 32, - .ivsize = 32, - }, -}; - -static struct fscrypt_mode * -select_encryption_mode(const struct fscrypt_info *ci, const struct inode *inode) -{ - if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) { - fscrypt_warn(inode, - "Unsupported encryption modes (contents mode %d, filenames mode %d)", - ci->ci_data_mode, ci->ci_filename_mode); - return ERR_PTR(-EINVAL); - } - - if (S_ISREG(inode->i_mode)) - return &available_modes[ci->ci_data_mode]; - - if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) - return &available_modes[ci->ci_filename_mode]; - - WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n", - inode->i_ino, (inode->i_mode & S_IFMT)); - return ERR_PTR(-EINVAL); -} - -/* Create a symmetric cipher object for the given encryption mode and key */ -struct crypto_skcipher *fscrypt_allocate_skcipher(struct fscrypt_mode *mode, - const u8 *raw_key, - const struct inode *inode) -{ - struct crypto_skcipher *tfm; - int err; - - tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0); - if (IS_ERR(tfm)) { - if (PTR_ERR(tfm) == -ENOENT) { - fscrypt_warn(inode, - "Missing crypto API support for %s (API name: \"%s\")", - mode->friendly_name, mode->cipher_str); - return ERR_PTR(-ENOPKG); - } - fscrypt_err(inode, "Error allocating '%s' transform: %ld", - mode->cipher_str, PTR_ERR(tfm)); - return tfm; - } - if (unlikely(!mode->logged_impl_name)) { - /* - * fscrypt performance can vary greatly depending on which - * crypto algorithm implementation is used. Help people debug - * performance problems by logging the ->cra_driver_name the - * first time a mode is used. Note that multiple threads can - * race here, but it doesn't really matter. - */ - mode->logged_impl_name = true; - pr_info("fscrypt: %s using implementation \"%s\"\n", - mode->friendly_name, - crypto_skcipher_alg(tfm)->base.cra_driver_name); - } - crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); - err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize); - if (err) - goto err_free_tfm; - - return tfm; - -err_free_tfm: - crypto_free_skcipher(tfm); - return ERR_PTR(err); -} - -static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt) -{ - struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm); - - /* init hash transform on demand */ - if (unlikely(!tfm)) { - struct crypto_shash *prev_tfm; - - tfm = crypto_alloc_shash("sha256", 0, 0); - if (IS_ERR(tfm)) { - if (PTR_ERR(tfm) == -ENOENT) { - fscrypt_warn(NULL, - "Missing crypto API support for SHA-256"); - return -ENOPKG; - } - fscrypt_err(NULL, - "Error allocating SHA-256 transform: %ld", - PTR_ERR(tfm)); - return PTR_ERR(tfm); - } - prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm); - if (prev_tfm) { - crypto_free_shash(tfm); - tfm = prev_tfm; - } - } - - { - SHASH_DESC_ON_STACK(desc, tfm); - desc->tfm = tfm; - - return crypto_shash_digest(desc, key, keysize, salt); - } -} - -static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key, - int keysize) -{ - int err; - struct crypto_cipher *essiv_tfm; - u8 salt[SHA256_DIGEST_SIZE]; - - if (WARN_ON(ci->ci_mode->ivsize != AES_BLOCK_SIZE)) - return -EINVAL; - - essiv_tfm = crypto_alloc_cipher("aes", 0, 0); - if (IS_ERR(essiv_tfm)) - return PTR_ERR(essiv_tfm); - - ci->ci_essiv_tfm = essiv_tfm; - - err = derive_essiv_salt(raw_key, keysize, salt); - if (err) - goto out; - - /* - * Using SHA256 to derive the salt/key will result in AES-256 being - * used for IV generation. File contents encryption will still use the - * configured keysize (AES-128) nevertheless. - */ - err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt)); - if (err) - goto out; - -out: - memzero_explicit(salt, sizeof(salt)); - return err; -} - -/* Given the per-file key, set up the file's crypto transform object(s) */ -int fscrypt_set_derived_key(struct fscrypt_info *ci, const u8 *derived_key) -{ - struct fscrypt_mode *mode = ci->ci_mode; - struct crypto_skcipher *ctfm; - int err; - - ctfm = fscrypt_allocate_skcipher(mode, derived_key, ci->ci_inode); - if (IS_ERR(ctfm)) - return PTR_ERR(ctfm); - - ci->ci_ctfm = ctfm; - - if (mode->needs_essiv) { - err = init_essiv_generator(ci, derived_key, mode->keysize); - if (err) { - fscrypt_warn(ci->ci_inode, - "Error initializing ESSIV generator: %d", - err); - return err; - } - } - return 0; -} - -/* - * Find the master key, then set up the inode's actual encryption key. - */ -static int setup_file_encryption_key(struct fscrypt_info *ci) -{ - return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci); -} - -static void put_crypt_info(struct fscrypt_info *ci) -{ - if (!ci) - return; - - if (ci->ci_direct_key) { - fscrypt_put_direct_key(ci->ci_direct_key); - } else { - crypto_free_skcipher(ci->ci_ctfm); - crypto_free_cipher(ci->ci_essiv_tfm); - } - kmem_cache_free(fscrypt_info_cachep, ci); -} - -int fscrypt_get_encryption_info(struct inode *inode) -{ - struct fscrypt_info *crypt_info; - struct fscrypt_context ctx; - struct fscrypt_mode *mode; - int res; - - if (fscrypt_has_encryption_key(inode)) - return 0; - - res = fscrypt_initialize(inode->i_sb->s_cop->flags); - if (res) - return res; - - res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); - if (res < 0) { - if (!fscrypt_dummy_context_enabled(inode) || - IS_ENCRYPTED(inode)) { - fscrypt_warn(inode, - "Error %d getting encryption context", - res); - return res; - } - /* Fake up a context for an unencrypted directory */ - memset(&ctx, 0, sizeof(ctx)); - ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; - ctx.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS; - ctx.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS; - memset(ctx.master_key_descriptor, 0x42, - FSCRYPT_KEY_DESCRIPTOR_SIZE); - } else if (res != sizeof(ctx)) { - fscrypt_warn(inode, - "Unknown encryption context size (%d bytes)", res); - return -EINVAL; - } - - if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1) { - fscrypt_warn(inode, "Unknown encryption context version (%d)", - ctx.format); - return -EINVAL; - } - - if (ctx.flags & ~FSCRYPT_POLICY_FLAGS_VALID) { - fscrypt_warn(inode, "Unknown encryption context flags (0x%02x)", - ctx.flags); - return -EINVAL; - } - - crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS); - if (!crypt_info) - return -ENOMEM; - - crypt_info->ci_inode = inode; - - crypt_info->ci_flags = ctx.flags; - crypt_info->ci_data_mode = ctx.contents_encryption_mode; - crypt_info->ci_filename_mode = ctx.filenames_encryption_mode; - memcpy(crypt_info->ci_master_key_descriptor, ctx.master_key_descriptor, - FSCRYPT_KEY_DESCRIPTOR_SIZE); - memcpy(crypt_info->ci_nonce, ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE); - - mode = select_encryption_mode(crypt_info, inode); - if (IS_ERR(mode)) { - res = PTR_ERR(mode); - goto out; - } - WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE); - crypt_info->ci_mode = mode; - - res = setup_file_encryption_key(crypt_info); - if (res) - goto out; - - if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) - crypt_info = NULL; -out: - if (res == -ENOKEY) - res = 0; - put_crypt_info(crypt_info); - return res; -} -EXPORT_SYMBOL(fscrypt_get_encryption_info); - -/** - * fscrypt_put_encryption_info - free most of an inode's fscrypt data - * - * Free the inode's fscrypt_info. Filesystems must call this when the inode is - * being evicted. An RCU grace period need not have elapsed yet. - */ -void fscrypt_put_encryption_info(struct inode *inode) -{ - put_crypt_info(inode->i_crypt_info); - inode->i_crypt_info = NULL; -} -EXPORT_SYMBOL(fscrypt_put_encryption_info); - -/** - * fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay - * - * Free the inode's cached decrypted symlink target, if any. Filesystems must - * call this after an RCU grace period, just before they free the inode. - */ -void fscrypt_free_inode(struct inode *inode) -{ - if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) { - kfree(inode->i_link); - inode->i_link = NULL; - } -} -EXPORT_SYMBOL(fscrypt_free_inode); |