From 9c8caf5aca7527235afcbbb813e9bf490a239dee Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Thu, 18 Oct 2018 16:37:12 +0200 Subject: mkfs.ubifs: Compute encryption key descriptor automatically ...if none is given. To be compatible with fscryptctl. Signed-off-by: Richard Weinberger Signed-off-by: David Oberhollenzer --- ubifs-utils/mkfs.ubifs/crypto.c | 27 ++++++++++++++++++++++++--- ubifs-utils/mkfs.ubifs/crypto.h | 1 + ubifs-utils/mkfs.ubifs/fscrypt.c | 11 ++++++++--- ubifs-utils/mkfs.ubifs/mkfs.ubifs.c | 2 -- 4 files changed, 33 insertions(+), 8 deletions(-) diff --git a/ubifs-utils/mkfs.ubifs/crypto.c b/ubifs-utils/mkfs.ubifs/crypto.c index d0f24e1..50a09b5 100644 --- a/ubifs-utils/mkfs.ubifs/crypto.c +++ b/ubifs-utils/mkfs.ubifs/crypto.c @@ -26,7 +26,7 @@ #include "fscrypt.h" #include "common.h" -static int do_sha256(const unsigned char *in, size_t len, unsigned char *out) +static int do_hash(const EVP_MD *md, const unsigned char *in, size_t len, unsigned char *out) { unsigned int out_len; EVP_MD_CTX *mdctx = EVP_MD_CTX_create(); @@ -34,7 +34,7 @@ static int do_sha256(const unsigned char *in, size_t len, unsigned char *out) if (!mdctx) return -1; - if (EVP_DigestInit_ex(mdctx, EVP_sha256(), NULL) != 1) + if (EVP_DigestInit_ex(mdctx, md, NULL) != 1) return -1; if(EVP_DigestUpdate(mdctx, in, len) != 1) @@ -121,7 +121,7 @@ static size_t gen_essiv_salt(const void *iv, size_t iv_len, const void *key, siz return -1; } - if (do_sha256(key, key_len, sha256) != 0) { + if (do_hash(EVP_sha256(), key, key_len, sha256) != 0) { errmsg("sha256 failed"); return -1; } @@ -288,6 +288,27 @@ ssize_t derive_key_aes(const void *deriving_key, const void *source_key, aes_key_len, NULL, 0, derived_key); } +int derive_key_descriptor(const void *source_key, void *descriptor) +{ + int ret = -1; + void *hash1 = xzalloc(EVP_MD_size(EVP_sha512())); + void *hash2 = xzalloc(EVP_MD_size(EVP_sha512())); + + if (do_hash(EVP_sha512(), source_key, FS_MAX_KEY_SIZE, hash1) != 0) + goto out; + + if (do_hash(EVP_sha512(), hash1, EVP_MD_size(EVP_sha512()), hash2) != 0) + goto out; + + memcpy(descriptor, hash2, FS_KEY_DESCRIPTOR_SIZE); + + ret = 0; +out: + free(hash1); + free(hash2); + return ret; +} + static struct cipher ciphers[] = { { .name = "AES-128-CBC", diff --git a/ubifs-utils/mkfs.ubifs/crypto.h b/ubifs-utils/mkfs.ubifs/crypto.h index c2631dd..f275839 100644 --- a/ubifs-utils/mkfs.ubifs/crypto.h +++ b/ubifs-utils/mkfs.ubifs/crypto.h @@ -49,6 +49,7 @@ void crypto_cleanup(void); ssize_t derive_key_aes(const void *deriving_key, const void *source_key, size_t source_key_len, void *derived_key); +int derive_key_descriptor(const void *source_key, void *descriptor); struct cipher *get_cipher(const char *name); diff --git a/ubifs-utils/mkfs.ubifs/fscrypt.c b/ubifs-utils/mkfs.ubifs/fscrypt.c index b9f9acc..ce6e2fc 100644 --- a/ubifs-utils/mkfs.ubifs/fscrypt.c +++ b/ubifs-utils/mkfs.ubifs/fscrypt.c @@ -242,12 +242,17 @@ struct fscrypt_context *init_fscrypt_context(const char *cipher_name, return NULL; } - if (parse_key_descriptor(key_descriptor, master_key_descriptor)) - return NULL; - if (load_master_key(key_file, fscrypt_cipher)) return NULL; + if (!key_descriptor) { + if (derive_key_descriptor(fscrypt_masterkey, master_key_descriptor)) + return NULL; + } else { + if (parse_key_descriptor(key_descriptor, master_key_descriptor)) + return NULL; + } + RAND_bytes((void *)nonce, FS_KEY_DERIVATION_NONCE_SIZE); new_fctx = xmalloc(sizeof(*new_fctx)); diff --git a/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c b/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c index 9bd15a2..f8d8e52 100644 --- a/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c +++ b/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c @@ -752,8 +752,6 @@ static int get_options(int argc, char**argv) if (key_file || key_desc) { if (!key_file) return err_msg("no key file specified"); - if (!key_desc) - return err_msg("no key descriptor specified"); c->double_hash = 1; c->encrypted = 1; -- cgit v1.2.3