Add OSSL_PARAM_construct_from_text() and OSSL_PARAM_allocate_from_text()
authorRichard Levitte <levitte@openssl.org>
Wed, 3 Jul 2019 16:42:21 +0000 (18:42 +0200)
committerRichard Levitte <levitte@openssl.org>
Mon, 12 Aug 2019 10:50:41 +0000 (12:50 +0200)
These are utility functions that can be used to replace calls to
ctrl_str type functions with get_params / set_params types of calls.
They work by translating text values to something more suitable for
OSSL_PARAM, and by interpretting parameter keys in a compatible
fashion.

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9303)

crypto/build.info
crypto/params_from_text.c [new file with mode: 0644]
doc/man3/OSSL_PARAM_construct_from_text.pod [new file with mode: 0644]
include/openssl/params.h
util/libcrypto.num

index 0b203a7..2130382 100644 (file)
@@ -67,7 +67,7 @@ SOURCE[../providers/fips]=$CORE_COMMON
 
 # Central utilities
 $UTIL_COMMON=\
-        cryptlib.c params.c bsearch.c ex_data.c o_str.c \
+        cryptlib.c params.c params_from_text.c bsearch.c ex_data.c o_str.c \
         ctype.c threads_pthread.c threads_win.c threads_none.c initthread.c \
         context.c sparse_array.c asn1_dsa.c packet.c param_build.c $CPUIDASM
 $UTIL_DEFINE=$CPUIDDEF
diff --git a/crypto/params_from_text.c b/crypto/params_from_text.c
new file mode 100644 (file)
index 0000000..2a861c9
--- /dev/null
@@ -0,0 +1,219 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <string.h>
+#include <openssl/err.h>
+#include <openssl/params.h>
+
+/*
+ * When processing text to params, we're trying to be smart with numbers.
+ * Instead of handling each specific separate integer type, we use a bignum
+ * and ensure that it isn't larger than the expected size, and we then make
+ * sure it is the expected size...  if there is one given.
+ * (if the size can be arbitrary, then we give whatever we have)
+ */
+
+static int prepare_from_text(const OSSL_PARAM *paramdefs, const char *key,
+                             const char *value, size_t value_n,
+                             /* Output parameters */
+                             const OSSL_PARAM **paramdef, int *ishex,
+                             size_t *buf_n, BIGNUM **tmpbn)
+{
+    const OSSL_PARAM *p;
+
+    /*
+     * ishex is used to translate legacy style string controls in hex format
+     * to octet string parameters.
+     */
+    *ishex = strncmp(key, "hex", 3) == 0;
+
+    if (*ishex)
+        key += 3;
+
+    p = *paramdef = OSSL_PARAM_locate_const(paramdefs, key);
+    if (p == NULL)
+        return 0;
+
+    switch (p->data_type) {
+    case OSSL_PARAM_INTEGER:
+    case OSSL_PARAM_UNSIGNED_INTEGER:
+        if (*ishex)
+            BN_hex2bn(tmpbn, value);
+        else
+            BN_dec2bn(tmpbn, value);
+
+        if (*tmpbn == NULL)
+            return 0;
+
+        /*
+         * 2s complement negate, part 1
+         *
+         * BN_bn2nativepad puts the absolute value of the number in the
+         * buffer, i.e. if it's negative, we need to deal with it.  We do
+         * it by subtracting 1 here and inverting the bytes in
+         * construct_from_text() below.
+         */
+        if (p->data_type == OSSL_PARAM_INTEGER && BN_is_negative(*tmpbn)
+            && !BN_sub_word(*tmpbn, 1)) {
+            return 0;
+        }
+
+        *buf_n = BN_num_bytes(*tmpbn);
+
+        /*
+         * TODO(v3.0) is this the right way to do this?  This code expects
+         * a zero data size to simply mean "arbitrary size".
+         */
+        if (p->data_size > 0) {
+            if (*buf_n >= p->data_size) {
+                CRYPTOerr(0, CRYPTO_R_TOO_SMALL_BUFFER);
+                /* Since this is a different error, we don't break */
+                return 0;
+            }
+            /* Change actual size to become the desired size. */
+            *buf_n = p->data_size;
+        }
+        break;
+    case OSSL_PARAM_UTF8_STRING:
+        if (*ishex) {
+            CRYPTOerr(0, ERR_R_PASSED_INVALID_ARGUMENT);
+            return 0;
+        }
+        *buf_n = strlen(value) + 1;
+        break;
+    case OSSL_PARAM_OCTET_STRING:
+        if (*ishex) {
+            *buf_n = strlen(value) >> 1;
+        }
+        break;
+    }
+
+    return 1;
+}
+
+static int construct_from_text(OSSL_PARAM *to, const OSSL_PARAM *paramdef,
+                               const char *value, size_t value_n, int ishex,
+                               void *buf, size_t buf_n, BIGNUM *tmpbn)
+{
+    if (buf == NULL)
+        return 0;
+
+    switch (paramdef->data_type) {
+    case OSSL_PARAM_INTEGER:
+    case OSSL_PARAM_UNSIGNED_INTEGER:
+        /*
+        {
+            if ((new_value = OPENSSL_malloc(new_value_n)) == NULL) {
+                BN_free(a);
+                break;
+            }
+        */
+
+        BN_bn2nativepad(tmpbn, buf, buf_n);
+
+        /*
+         * 2s complement negate, part two.
+         *
+         * Because we did the first part on the BIGNUM itself, we can just
+         * invert all the bytes here and be done with it.
+         */
+        if (paramdef->data_type == OSSL_PARAM_INTEGER
+            && BN_is_negative(tmpbn)) {
+            unsigned char *cp;
+            size_t i = buf_n;
+
+            for (cp = buf; i-- > 0; cp++)
+                *cp ^= 0xFF;
+        }
+        break;
+    case OSSL_PARAM_UTF8_STRING:
+        strncpy(buf, value, buf_n);
+        break;
+    case OSSL_PARAM_OCTET_STRING:
+        if (ishex) {
+            size_t l = 0;
+
+            if (!OPENSSL_hexstr2buf_ex(buf, buf_n, &l, value))
+                return 0;
+        } else {
+            memcpy(buf, value, buf_n);
+
+        }
+        break;
+    }
+
+    *to = *paramdef;
+    to->data = buf;
+    to->data_size = buf_n;
+    to->return_size = 0;
+
+    return 1;
+}
+
+int OSSL_PARAM_construct_from_text(OSSL_PARAM *to,
+                                   const OSSL_PARAM *paramdefs,
+                                   const char *key, const char *value,
+                                   size_t value_n,
+                                   void *buf, size_t *buf_n)
+{
+    const OSSL_PARAM *paramdef = NULL;
+    int ishex = 0;
+    BIGNUM *tmpbn = NULL;
+    int ok = 0;
+
+    if (to == NULL || paramdefs == NULL)
+        return 0;
+
+    if (!prepare_from_text(paramdefs, key, value, value_n,
+                           &paramdef, &ishex, buf_n, &tmpbn))
+        return 0;
+
+    /*
+     * The user gets the expected buffer size back even if the buffer isn't
+     * allocated.
+     */
+    if (buf == NULL)
+        return 1;
+
+    ok = construct_from_text(to, paramdef, value, value_n, ishex,
+                             buf, *buf_n, tmpbn);
+    BN_free(tmpbn);
+    return ok;
+}
+
+int OSSL_PARAM_allocate_from_text(OSSL_PARAM *to,
+                                  const OSSL_PARAM *paramdefs,
+                                  const char *key, const char *value,
+                                  size_t value_n)
+{
+    const OSSL_PARAM *paramdef = NULL;
+    int ishex = 0;
+    void *buf = NULL;
+    size_t buf_n = 0;
+    BIGNUM *tmpbn = NULL;
+    int ok = 0;
+
+    if (to == NULL || paramdefs == NULL)
+        return 0;
+
+    if (!prepare_from_text(paramdefs, key, value, value_n,
+                           &paramdef, &ishex, &buf_n, &tmpbn))
+        return 0;
+
+    if ((buf = OPENSSL_malloc(buf_n)) == NULL) {
+        CRYPTOerr(0, ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+
+    ok = construct_from_text(to, paramdef, value, value_n, ishex,
+                             buf, buf_n, tmpbn);
+    BN_free(tmpbn);
+    return ok;
+}
diff --git a/doc/man3/OSSL_PARAM_construct_from_text.pod b/doc/man3/OSSL_PARAM_construct_from_text.pod
new file mode 100644 (file)
index 0000000..28d5e6f
--- /dev/null
@@ -0,0 +1,167 @@
+=pod
+
+=head1 NAME
+
+OSSL_PARAM_construct_from_text, OSSL_PARAM_allocate_from_text
+- OSSL_PARAM construction utilities
+
+=head1 SYNOPSIS
+
+ #include <openssl/params.h>
+
+ int OSSL_PARAM_construct_from_text(OSSL_PARAM *to,
+                                    const OSSL_PARAM *paramdefs,
+                                    const char *key, const char *value,
+                                    size_t value_n,
+                                    void *buf, size_t *buf_n)
+ int OSSL_PARAM_allocate_from_text(OSSL_PARAM *to,
+                                   const OSSL_PARAM *paramdefs,
+                                   const char *key, const char *value,
+                                   size_t value_n);
+
+=head1 DESCRIPTION
+
+With OpenSSL before version 3.0, parameters were passed down to or
+retrieved from algorithm implementations via control functions.
+Some of these control functions existed in variants that took string
+parameters, for example L<EVP_PKEY_CTX_ctrl_str(3)>.
+
+OpenSSL 3.0 introduces a new mechanism to do the same thing with an
+array of parameters that contain name, value, value type and value
+size (see L<OSSL_PARAM(3)> for more information).
+
+OSSL_PARAM_construct_from_text() takes a control I<key>, I<value> and
+value size I<value_n>, and given a parameter descriptor array
+I<paramdefs>, it converts the value to something suitable for
+L<OSSL_PARAM(3)> and stores that in the buffer I<buf>, and modifies
+the parameter I<to> to match.
+I<buf_n>, if not NULL, will be assigned the number of bytes used in
+I<buf>.
+If I<buf> is NULL, only I<buf_n> will be modified, everything else is
+left untouched, allowing a caller to find out how large the buffer
+should be.
+I<buf> needs to be correctly aligned for the type of the B<OSSL_PARAM>
+I<key>.
+
+OSSL_PARAM_allocate_from_text() works like OSSL_PARAM_construct_from_text(),
+except it allocates the buffer internally.
+The caller must remember to free the data of I<to> when it's not
+useful any more.
+
+For parameters having the type B<OSSL_PARAM_INTEGER>,
+B<OSSL_PARAM_UNSIGNED_INTEGER>, or B<OSSL_PARAM_OCTET_STRING>, both
+functions will interpret the I<value> differently if the key starts
+with "hex".
+In that case, the value is decoded first, and the result will be used
+as parameter value.
+
+=head1 RETURN VALUES
+
+OSSL_PARAM_construct_from_text() and OSSL_PARAM_allocate_from_text()
+returns 1 on success, and 0 on error.
+
+=head1 NOTES
+
+The parameter descriptor array comes from functions dedicated to
+return them.
+The following B<OSSL_PARAM> attributes are used:
+
+=over 4
+
+=item I<key>
+
+=item I<data>
+
+=item I<data_size>
+
+=back
+
+All other attributes are ignored.
+
+The I<data_size> attribute can be zero, meaning that the parameter it
+describes expects arbitrary length data.
+
+=head1 EXAMPLE
+
+Code that looked like this:
+
+  int mac_ctrl_string(EVP_PKEY_CTX *ctx, const char *value)
+  {
+      int rv;
+      char *stmp, *vtmp = NULL;
+      stmp = OPENSSL_strdup(value);
+      if (!stmp)
+          return -1;
+      vtmp = strchr(stmp, ':');
+      if (vtmp) {
+          *vtmp = 0;
+          vtmp++;
+      }
+      rv = EVP_MAC_ctrl_str(ctx, stmp, vtmp);
+      OPENSSL_free(stmp);
+      return rv;
+  }
+
+  ...
+
+
+  char *macopt;
+  for (i = 0; i < sk_OPENSSL_STRING_num(macopts); i++) {
+      macopt = sk_OPENSSL_STRING_value(macopts, i);
+      if (pkey_ctrl_string(mac_ctx, macopt) <= 0) {
+          BIO_printf(bio_err,
+                     "MAC parameter error \"%s\"\n", macopt);
+          ERR_print_errors(bio_err);
+          goto mac_end;
+      }
+  }
+
+Can be written like this instead:
+
+  OSSL_PARAM *params =
+      OPENSSL_zalloc(sizeof(OSSL_PARAM)
+                     * (sk_OPENSSL_STRING_num(opts) + 1));
+  const OSSL_PARAM *paramdefs = EVP_MAC_CTX_set_param_types(mac);
+  size_t params_n;
+
+  for (params_n = 0; params_n < (size_t)sk_OPENSSL_STRING_num(opts);
+       params_n++) {
+      char *opt = sk_OPENSSL_STRING_value(opts, (int)params_n);
+      char *stmp, *vtmp = NULL;
+
+      if ((stmp = OPENSSL_strdup(opt)) == NULL
+          || (vtmp = strchr(stmp, ':')) == NULL
+          || (*vtmp++ = '\0') /* Always zero */
+          || !OSSL_PARAM_allocate_from_text(&params[params_n],
+                                            paramdefs,
+                                            stmp, vtmp, strlen(vtmp))) {
+          BIO_printf(bio_err, "MAC parameter error '%s'\n", opt);
+          ERR_print_errors(bio_err);
+          goto err;
+      }
+  }
+  params[params_n] = OSSL_PARAM_construct_end();
+  if (!EVP_MAC_CTX_set_params(ctx, params)) {
+      BIO_printf(bio_err, "MAC parameter error\n");
+      ERR_print_errors(bio_err);
+      goto err;
+  }
+  for (; params_n-- > 0;) {
+      OPENSSL_free(params[params_n].data);
+  }
+  OPENSSL_free(params);
+
+=head1 SEE ALSO
+
+L<OSSL_PARAM(3)>, L<OSSL_PARAM_TYPE(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the Apache License 2.0 (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut
index 0e830de..8293ee2 100644 (file)
@@ -89,6 +89,16 @@ OSSL_PARAM OSSL_PARAM_construct_octet_ptr(const char *key, void **buf,
                                           size_t bsize);
 OSSL_PARAM OSSL_PARAM_construct_end(void);
 
+int OSSL_PARAM_construct_from_text(OSSL_PARAM *to,
+                                   const OSSL_PARAM *paramdefs,
+                                   const char *key, const char *value,
+                                   size_t value_n,
+                                   void *buf, size_t *buf_n);
+int OSSL_PARAM_allocate_from_text(OSSL_PARAM *to,
+                                  const OSSL_PARAM *paramdefs,
+                                  const char *key, const char *value,
+                                  size_t value_n);
+
 int OSSL_PARAM_get_int(const OSSL_PARAM *p, int *val);
 int OSSL_PARAM_get_uint(const OSSL_PARAM *p, unsigned int *val);
 int OSSL_PARAM_get_long(const OSSL_PARAM *p, long int *val);
index c6f1f2d..ac861fe 100644 (file)
@@ -4708,3 +4708,5 @@ EC_KEY_new_ex                           4817      3_0_0   EXIST::FUNCTION:EC
 EC_KEY_new_by_curve_name_ex             4818   3_0_0   EXIST::FUNCTION:EC
 OPENSSL_hexstr2buf_ex                   4819   3_0_0   EXIST::FUNCTION:
 OPENSSL_buf2hexstr_ex                   4820   3_0_0   EXIST::FUNCTION:
+OSSL_PARAM_construct_from_text          4821   3_0_0   EXIST::FUNCTION:
+OSSL_PARAM_allocate_from_text           4822   3_0_0   EXIST::FUNCTION: