Digest string helper function.

New function EVP_PKEY_CTX_md() which takes a string and passes a digest
to a ctrl.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2177)

crypto/evp/evp_err.c

@@ -50,6 +50,7 @@ static ERR_STRING_DATA EVP_str_functs[] = {
     {ERR_FUNC(EVP_F_EVP_PKEY_CTX_CTRL), "EVP_PKEY_CTX_ctrl"},
     {ERR_FUNC(EVP_F_EVP_PKEY_CTX_CTRL_STR), "EVP_PKEY_CTX_ctrl_str"},
     {ERR_FUNC(EVP_F_EVP_PKEY_CTX_DUP), "EVP_PKEY_CTX_dup"},
+    {ERR_FUNC(EVP_F_EVP_PKEY_CTX_MD), "EVP_PKEY_CTX_md"},
     {ERR_FUNC(EVP_F_EVP_PKEY_DECRYPT), "EVP_PKEY_decrypt"},
     {ERR_FUNC(EVP_F_EVP_PKEY_DECRYPT_INIT), "EVP_PKEY_decrypt_init"},
     {ERR_FUNC(EVP_F_EVP_PKEY_DECRYPT_OLD), "EVP_PKEY_decrypt_old"},

crypto/evp/pmeth_lib.c

@@ -330,14 +330,9 @@ int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx,
         EVPerr(EVP_F_EVP_PKEY_CTX_CTRL_STR, EVP_R_COMMAND_NOT_SUPPORTED);
         return -2;
     }
-    if (strcmp(name, "digest") == 0) {
-        const EVP_MD *md;
-        if (value == NULL || (md = EVP_get_digestbyname(value)) == NULL) {
-            EVPerr(EVP_F_EVP_PKEY_CTX_CTRL_STR, EVP_R_INVALID_DIGEST);
-            return 0;
-        }
-        return EVP_PKEY_CTX_set_signature_md(ctx, md);
-    }
+    if (strcmp(name, "digest") == 0)
+        return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_TYPE_SIG, EVP_PKEY_CTRL_MD,
+                               value);
     return ctx->pmeth->ctrl_str(ctx, name, value);
 }
 
@@ -367,6 +362,16 @@ int EVP_PKEY_CTX_hex2ctrl(EVP_PKEY_CTX *ctx, int cmd, const char *hex)
     OPENSSL_free(bin);
     return rv;
 }
+/* Pass a message digest to a ctrl */
+int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md)
+{
+    const EVP_MD *m;
+    if (md == NULL || (m = EVP_get_digestbyname(md)) == NULL) {
+        EVPerr(EVP_F_EVP_PKEY_CTX_MD, EVP_R_INVALID_DIGEST);
+        return 0;
+    }
+    return EVP_PKEY_CTX_ctrl(ctx, -1, optype, cmd, 0, (void *)m);
+}
 
 int EVP_PKEY_CTX_get_operation(EVP_PKEY_CTX *ctx)
 {

crypto/rsa/rsa_pmeth.c

@@ -572,14 +572,10 @@ static int pkey_rsa_ctrl_str(EVP_PKEY_CTX *ctx,
         return ret;
     }
 
-    if (strcmp(type, "rsa_mgf1_md") == 0) {
-        const EVP_MD *md;
-        if ((md = EVP_get_digestbyname(value)) == NULL) {
-            RSAerr(RSA_F_PKEY_RSA_CTRL_STR, RSA_R_INVALID_DIGEST);
-            return 0;
-        }
-        return EVP_PKEY_CTX_set_rsa_mgf1_md(ctx, md);
-    }
+    if (strcmp(type, "rsa_mgf1_md") == 0)
+        return EVP_PKEY_CTX_md(ctx,
+                               EVP_PKEY_OP_TYPE_SIG | EVP_PKEY_OP_TYPE_CRYPT,
+                               EVP_PKEY_CTRL_RSA_MGF1_MD, value);
 
     if (strcmp(type, "rsa_oaep_md") == 0) {
         const EVP_MD *md;
@@ -587,8 +583,12 @@ static int pkey_rsa_ctrl_str(EVP_PKEY_CTX *ctx,
             RSAerr(RSA_F_PKEY_RSA_CTRL_STR, RSA_R_INVALID_DIGEST);
             return 0;
         }
-        return EVP_PKEY_CTX_set_rsa_oaep_md(ctx, md);
     }
+
+    if (strcmp(type, "rsa_oaep_md") == 0)
+        return EVP_PKEY_CTX_md(ctx, EVP_PKEY_OP_TYPE_CRYPT,
+                               EVP_PKEY_CTRL_RSA_OAEP_MD, value);
+
     if (strcmp(type, "rsa_oaep_label") == 0) {
         unsigned char *lab;
         long lablen;

include/openssl/evp.h

@@ -1205,6 +1205,8 @@ int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
 int EVP_PKEY_CTX_str2ctrl(EVP_PKEY_CTX *ctx, int cmd, const char *str);
 int EVP_PKEY_CTX_hex2ctrl(EVP_PKEY_CTX *ctx, int cmd, const char *hex);
 
+int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md);
+
 int EVP_PKEY_CTX_get_operation(EVP_PKEY_CTX *ctx);
 void EVP_PKEY_CTX_set0_keygen_info(EVP_PKEY_CTX *ctx, int *dat, int datlen);
 
@@ -1484,6 +1486,7 @@ int ERR_load_EVP_strings(void);
 # define EVP_F_EVP_PKEY_CTX_CTRL                          137
 # define EVP_F_EVP_PKEY_CTX_CTRL_STR                      150
 # define EVP_F_EVP_PKEY_CTX_DUP                           156
+# define EVP_F_EVP_PKEY_CTX_MD                            168
 # define EVP_F_EVP_PKEY_DECRYPT                           104
 # define EVP_F_EVP_PKEY_DECRYPT_INIT                      138
 # define EVP_F_EVP_PKEY_DECRYPT_OLD                       151