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authorEric Biggers <ebiggers@google.com>2019-08-04 19:35:45 -0700
committerEric Biggers <ebiggers@google.com>2019-08-12 19:06:06 -0700
commitfeed825861919ac3fac4b2ab83673dd5225f7f0d (patch)
tree847366a45149de2bd984b0b3bc4c44ced1c3e838 /fs/crypto/keyinfo.c
parentfscrypt: move v1 policy key setup to keysetup_v1.c (diff)
downloadlinux-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.c345
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);