dcrypt-openssl: Implement signature API for OpenSSL

diff --git a/src/lib-dcrypt/dcrypt-openssl.c b/src/lib-dcrypt/dcrypt-openssl.c
index d1ce9a6c41bd83721b9c408ca5dc6d10405bd6b2..ae3b1dcc107289719e4f4d9bd63faf2d493c001d 100644 (file)
--- a/src/lib-dcrypt/dcrypt-openssl.c
+++ b/src/lib-dcrypt/dcrypt-openssl.c
@@ -3130,6 +3130,101 @@ dcrypt_openssl_private_key_id(struct dcrypt_private_key *key,
        return dcrypt_openssl_public_key_id_evp(priv, md, result, error_r);
 }
 
+static bool
+dcrypt_openssl_sign(struct dcrypt_private_key *key, const char *algorithm,
+                   const void *data, size_t data_len, buffer_t *signature_r,
+                   enum dcrypt_padding padding, const char **error_r)
+{
+       EVP_PKEY_CTX *pctx = NULL;
+       EVP_MD_CTX *dctx;
+       bool ret;
+       const EVP_MD *md = EVP_get_digestbyname(algorithm);
+       size_t siglen;
+       int pad = dcrypt_openssl_padding_mode(padding, TRUE, error_r);
+
+       if (pad == -1)
+               return FALSE;
+
+       if (md == NULL) {
+               if (error_r != NULL) {
+                        *error_r = t_strdup_printf(
+                               "Unknown digest %s", algorithm);
+               }
+               return FALSE;
+       }
+
+       dctx = EVP_MD_CTX_create();
+
+       /* NB! Padding is set only on RSA signatures
+          ECDSA signatures use whatever is default */
+       if (EVP_DigestSignInit(dctx, &pctx, md, NULL, key->key) != 1 ||
+           (EVP_PKEY_base_id(key->key) == EVP_PKEY_RSA &&
+            EVP_PKEY_CTX_set_rsa_padding(pctx, pad) != 1) ||
+           EVP_DigestSignUpdate(dctx, data, data_len) != 1 ||
+           EVP_DigestSignFinal(dctx, NULL, &siglen) != 1) {
+               ret = dcrypt_openssl_error(error_r);
+       } else {
+               i_assert(siglen > 0);
+               /* @UNSAFE */
+               unsigned char *buf =
+                       buffer_append_space_unsafe(signature_r, siglen);
+               if (EVP_DigestSignFinal(dctx, buf, &siglen) != 1) {
+                       ret = dcrypt_openssl_error(error_r);
+               } else {
+                       buffer_set_used_size(signature_r, siglen);
+                       ret = TRUE;
+               }
+       }
+
+       EVP_MD_CTX_destroy(dctx);
+
+       return ret;
+}
+
+static bool
+dcrypt_openssl_verify(struct dcrypt_public_key *key, const char *algorithm,
+                     const void *data, size_t data_len,
+                     const unsigned char *signature, size_t signature_len,
+                     bool *valid_r, enum dcrypt_padding padding,
+                     const char **error_r)
+{
+       EVP_PKEY_CTX *pctx = NULL;
+       EVP_MD_CTX *dctx;
+       bool ret;
+       const EVP_MD *md = EVP_get_digestbyname(algorithm);
+       int rc, pad = dcrypt_openssl_padding_mode(padding, TRUE, error_r);
+
+       if (pad == -1)
+               return FALSE;
+
+       if (md == NULL) {
+               if (error_r != NULL) {
+                        *error_r = t_strdup_printf(
+                               "Unknown digest %s", algorithm);
+               }
+               return FALSE;
+       }
+
+       dctx = EVP_MD_CTX_create();
+
+       /* NB! Padding is set only on RSA signatures
+          ECDSA signatures use whatever is default */
+       if (EVP_DigestVerifyInit(dctx, &pctx, md, NULL, key->key) != 1 ||
+           (EVP_PKEY_base_id(key->key) == EVP_PKEY_RSA &&
+            EVP_PKEY_CTX_set_rsa_padding(pctx, pad) != 1) ||
+           EVP_DigestVerifyUpdate(dctx, data, data_len) != 1 ||
+           (rc = EVP_DigestVerifyFinal(dctx, signature, signature_len)) < 0) {
+               ret = dcrypt_openssl_error(error_r);
+       } else {
+               /* return code 1 means valid signature, otherwise invalid */
+               *valid_r = (rc == 1);
+               ret = TRUE;
+       }
+
+       EVP_MD_CTX_destroy(dctx);
+
+       return ret;
+}
 
 static bool
 dcrypt_openssl_key_store_private_raw(struct dcrypt_private_key *key,
@@ -3550,6 +3645,8 @@ static struct dcrypt_vfs dcrypt_openssl_vfs = {
        .key_get_usage_private = dcrypt_openssl_key_get_usage_private,
        .key_set_usage_public = dcrypt_openssl_key_set_usage_public,
        .key_set_usage_private = dcrypt_openssl_key_set_usage_private,
+       .sign = dcrypt_openssl_sign,
+       .verify = dcrypt_openssl_verify,
 };
 
 void dcrypt_openssl_init(struct module *module ATTR_UNUSED)