From a8eb286adaa73e86305317b9cae15d41c57de8e7 Mon Sep 17 00:00:00 2001 From: Soby Mathew Date: Thu, 31 Aug 2017 11:50:29 +0100 Subject: [PATCH] cert_tool: Support for legacy RSA PKCS#1 v1.5 This patch enables choice of RSA version at run time to be used for generating signatures by the cert_tool. The RSA PSS as defined in PKCS#1 v2.1 becomes the default version and this patch enables to specify the RSA PKCS#1 v1.5 algorithm to `cert_create` through the command line -a option. Also, the build option `KEY_ALG` can be used to pass this option from the build system. Please note that RSA PSS is mandated by Trusted Board Boot requirements (TBBR) and legacy RSA support is being added for compatibility reasons. Fixes ARM-Software/tf-issues#499 Change-Id: Ifaa3f2f7c9b43f3d7b3effe2cde76bf6745a5d73 Co-Authored-By: Eleanor Bonnici Signed-off-by: Soby Mathew --- docs/user-guide.rst | 6 +++-- drivers/auth/mbedtls/mbedtls_crypto.mk | 2 +- tools/cert_create/include/cert.h | 2 +- tools/cert_create/include/key.h | 3 ++- tools/cert_create/src/cert.c | 34 ++++++++++++++++---------- tools/cert_create/src/main.c | 8 +++--- 6 files changed, 34 insertions(+), 21 deletions(-) diff --git a/docs/user-guide.rst b/docs/user-guide.rst index 1502c8c10..1181495cf 100644 --- a/docs/user-guide.rst +++ b/docs/user-guide.rst @@ -407,8 +407,10 @@ Common build options - ``KEY_ALG``: This build flag enables the user to select the algorithm to be used for generating the PKCS keys and subsequent signing of the certificate. - It accepts 2 values viz ``rsa``, ``ecdsa``. The default value of this flag - is ``rsa``. + It accepts 3 values viz ``rsa``, ``rsa_1_5``, ``ecdsa``. The ``rsa_1_5`` is + the legacy PKCS#1 RSA 1.5 algorithm which is not TBBR compliant and is + retained only for compatibility. The default value of this flag is ``rsa`` + which is the TBBR compliant PKCS#1 RSA 2.1 scheme. - ``LDFLAGS``: Extra user options appended to the linkers' command line in addition to the one set by the build system. diff --git a/drivers/auth/mbedtls/mbedtls_crypto.mk b/drivers/auth/mbedtls/mbedtls_crypto.mk index 38197164c..21b857bff 100644 --- a/drivers/auth/mbedtls/mbedtls_crypto.mk +++ b/drivers/auth/mbedtls/mbedtls_crypto.mk @@ -9,7 +9,7 @@ include drivers/auth/mbedtls/mbedtls_common.mk # The platform may define the variable 'TF_MBEDTLS_KEY_ALG' to select the key # algorithm to use. If the variable is not defined, select it based on algorithm # used for key generation `KEY_ALG`. If `KEY_ALG` is not defined or is -# defined to `rsa`, then set the variable to `rsa`. +# defined to `rsa`/`rsa_1_5`, then set the variable to `rsa`. ifeq (${TF_MBEDTLS_KEY_ALG},) ifeq (${KEY_ALG}, ecdsa) TF_MBEDTLS_KEY_ALG := ecdsa diff --git a/tools/cert_create/include/cert.h b/tools/cert_create/include/cert.h index 543f12233..256e7afd2 100644 --- a/tools/cert_create/include/cert.h +++ b/tools/cert_create/include/cert.h @@ -48,7 +48,7 @@ struct cert_s { int cert_init(void); cert_t *cert_get_by_opt(const char *opt); int cert_add_ext(X509 *issuer, X509 *subject, int nid, char *value); -int cert_new(cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk); +int cert_new(int key_alg, cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk); /* Macro to register the certificates used in the CoT */ #define REGISTER_COT(_certs) \ diff --git a/tools/cert_create/include/key.h b/tools/cert_create/include/key.h index 4b9e88258..304fa6154 100644 --- a/tools/cert_create/include/key.h +++ b/tools/cert_create/include/key.h @@ -22,7 +22,8 @@ enum { /* Supported key algorithms */ enum { - KEY_ALG_RSA, + KEY_ALG_RSA, /* RSA PSS as defined by PKCS#1 v2.1 (default) */ + KEY_ALG_RSA_1_5, /* RSA as defined by PKCS#1 v1.5 */ #ifndef OPENSSL_NO_EC KEY_ALG_ECDSA, #endif /* OPENSSL_NO_EC */ diff --git a/tools/cert_create/src/cert.c b/tools/cert_create/src/cert.c index 9775664a3..1b84e36d3 100644 --- a/tools/cert_create/src/cert.c +++ b/tools/cert_create/src/cert.c @@ -79,7 +79,7 @@ int cert_add_ext(X509 *issuer, X509 *subject, int nid, char *value) return 1; } -int cert_new(cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk) +int cert_new(int key_alg, cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk) { EVP_PKEY *pkey = keys[cert->key].key; cert_t *issuer_cert = &certs[cert->issuer]; @@ -90,7 +90,7 @@ int cert_new(cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk) X509_NAME *name; ASN1_INTEGER *sno; int i, num, rc = 0; - EVP_MD_CTX mdCtx; + EVP_MD_CTX mdCtx; EVP_PKEY_CTX *pKeyCtx = NULL; /* Create the certificate structure */ @@ -112,24 +112,32 @@ int cert_new(cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk) } EVP_MD_CTX_init(&mdCtx); + + /* Sign the certificate with the issuer key */ if (!EVP_DigestSignInit(&mdCtx, &pKeyCtx, EVP_sha256(), NULL, ikey)) { ERR_print_errors_fp(stdout); goto END; } - if (!EVP_PKEY_CTX_set_rsa_padding(pKeyCtx, RSA_PKCS1_PSS_PADDING)) { - ERR_print_errors_fp(stdout); - goto END; - } + /* + * Set additional parameters if algorithm is RSA PSS. This is not + * required for RSA 1.5 or ECDSA. + */ + if (key_alg == KEY_ALG_RSA) { + if (!EVP_PKEY_CTX_set_rsa_padding(pKeyCtx, RSA_PKCS1_PSS_PADDING)) { + ERR_print_errors_fp(stdout); + goto END; + } - if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pKeyCtx, RSA_SALT_LEN)) { - ERR_print_errors_fp(stdout); - goto END; - } + if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pKeyCtx, RSA_SALT_LEN)) { + ERR_print_errors_fp(stdout); + goto END; + } - if (!EVP_PKEY_CTX_set_rsa_mgf1_md(pKeyCtx, EVP_sha256())) { - ERR_print_errors_fp(stdout); - goto END; + if (!EVP_PKEY_CTX_set_rsa_mgf1_md(pKeyCtx, EVP_sha256())) { + ERR_print_errors_fp(stdout); + goto END; + } } /* x509.v3 */ diff --git a/tools/cert_create/src/main.c b/tools/cert_create/src/main.c index f14601c8b..df59961b0 100644 --- a/tools/cert_create/src/main.c +++ b/tools/cert_create/src/main.c @@ -89,6 +89,7 @@ static char *strdup(const char *str) static const char *key_algs_str[] = { [KEY_ALG_RSA] = "rsa", + [KEY_ALG_RSA_1_5] = "rsa_1_5", #ifndef OPENSSL_NO_EC [KEY_ALG_ECDSA] = "ecdsa" #endif /* OPENSSL_NO_EC */ @@ -223,7 +224,8 @@ static const cmd_opt_t common_cmd_opt[] = { }, { { "key-alg", required_argument, NULL, 'a' }, - "Key algorithm: 'rsa' (default), 'ecdsa'" + "Key algorithm: 'rsa' (default) - RSAPSS scheme as per \ +PKCS#1 v2.1, 'rsa_1_5' - RSA PKCS#1 v1.5, 'ecdsa'" }, { { "save-keys", no_argument, NULL, 'k' }, @@ -450,8 +452,8 @@ int main(int argc, char *argv[]) sk_X509_EXTENSION_push(sk, cert_ext); } - /* Create certificate. Signed with ROT key */ - if (cert->fn && !cert_new(cert, VAL_DAYS, 0, sk)) { + /* Create certificate. Signed with corresponding key */ + if (cert->fn && !cert_new(key_alg, cert, VAL_DAYS, 0, sk)) { ERROR("Cannot create %s\n", cert->cn); exit(1); }