Merge pull request #7552 from dgarske/ecies_own_salt

Add option for using a custom salt for ourselves
wolfSSL · May 20, 2024 · 43b2c80 · 43b2c80
2 parents 095906f + 5a0594d
commit 43b2c80
Show file tree

Hide file tree

Showing 3 changed files with 37 additions and 8 deletions.
diff --git a/doc/dox_comments/header_files/ecc.h b/doc/dox_comments/header_files/ecc.h
@@ -1722,7 +1722,7 @@ int wc_ecc_ctx_set_peer_salt(ecEncCtx* ctx, const byte* salt);
 
  \param ctx pointer to the ecEncCtx for which to set the salt
  \param salt pointer to salt buffer
- \param len length salt in bytes
+ \param sz length salt in bytes
 
  _Example_
  \code
@@ -1742,7 +1742,7 @@ int wc_ecc_ctx_set_peer_salt(ecEncCtx* ctx, const byte* salt);
  \sa wc_ecc_ctx_get_peer_salt
 */
 
-int wc_ecc_ctx_set_kdf_salt(ecEncCtx* ctx, const byte* salt, word32 len);
+int wc_ecc_ctx_set_kdf_salt(ecEncCtx* ctx, const byte* salt, word32 sz);
 
 /*!
  \ingroup ECC

diff --git a/wolfcrypt/src/ecc.c b/wolfcrypt/src/ecc.c
@@ -13830,17 +13830,17 @@ int wc_ecc_ctx_set_peer_salt(ecEncCtx* ctx, const byte* salt)
  *
  * @param [in, out] ctx ECIES context object.
  * @param [in] salt Salt to use with KDF.
- * @param [in] len Length of salt in bytes.
+ * @param [in] sz  Length of salt in bytes.
  * @return 0 on success.
  * @return BAD_FUNC_ARG when ctx is NULL or salt is NULL and len is not 0.
  */
-int wc_ecc_ctx_set_kdf_salt(ecEncCtx* ctx, const byte* salt, word32 len)
+int wc_ecc_ctx_set_kdf_salt(ecEncCtx* ctx, const byte* salt, word32 sz)
 {
- if (ctx == NULL || (salt == NULL && len != 0))
+ if (ctx == NULL || (salt == NULL && sz != 0))
  return BAD_FUNC_ARG;
 
  ctx->kdfSalt = salt;
- ctx->kdfSaltSz = len;
+ ctx->kdfSaltSz = sz;
 
  if (ctx->protocol == REQ_RESP_CLIENT) {
  ctx->cliSt = ecCLI_SALT_SET;
@@ -13852,9 +13852,37 @@ int wc_ecc_ctx_set_kdf_salt(ecEncCtx* ctx, const byte* salt, word32 len)
  return 0;
 }
 
+/* Set your own salt. By default we generate a random salt for ourselves.
+ * This allows overriding that after init or reset.
+ *
+ * @param [in, out] ctx ECIES context object.
+ * @param [in] salt Salt to use for ourselves
+ * @param [in] sz Length of salt in bytes.
+ * @return 0 on success.
+ * @return BAD_FUNC_ARG when ctx is NULL or salt is NULL and len is not 0.
+ */
+int wc_ecc_ctx_set_own_salt(ecEncCtx* ctx, const byte* salt, word32 sz)
+{
+ byte* saltBuffer;
+
+ if (ctx == NULL || ctx->protocol == 0 || salt == NULL)
+ return BAD_FUNC_ARG;
+
+ if (sz > EXCHANGE_SALT_SZ)
+ sz = EXCHANGE_SALT_SZ;
+ saltBuffer = (ctx->protocol == REQ_RESP_CLIENT) ?
+ ctx->clientSalt :
+ ctx->serverSalt;
+ XMEMSET(saltBuffer, 0, EXCHANGE_SALT_SZ);
+ XMEMCPY(saltBuffer, salt, sz);
+
+ return 0;
+}
+
+
 static int ecc_ctx_set_salt(ecEncCtx* ctx, int flags)
 {
- byte* saltBuffer = NULL;
+ byte* saltBuffer;
 
  if (ctx == NULL || flags == 0)
  return BAD_FUNC_ARG;
@@ -13864,7 +13892,6 @@ static int ecc_ctx_set_salt(ecEncCtx* ctx, int flags)
  return wc_RNG_GenerateBlock(ctx->rng, saltBuffer, EXCHANGE_SALT_SZ);
 }
 
-
 static void ecc_ctx_init(ecEncCtx* ctx, int flags, WC_RNG* rng)
 {
  if (ctx) {

diff --git a/wolfssl/wolfcrypt/ecc.h b/wolfssl/wolfcrypt/ecc.h
@@ -978,6 +978,8 @@ const byte* wc_ecc_ctx_get_own_salt(ecEncCtx* ctx);
 WOLFSSL_API
 int wc_ecc_ctx_set_peer_salt(ecEncCtx* ctx, const byte* salt);
 WOLFSSL_API
+int wc_ecc_ctx_set_own_salt(ecEncCtx* ctx, const byte* salt, word32 sz);
+WOLFSSL_API
 int wc_ecc_ctx_set_kdf_salt(ecEncCtx* ctx, const byte* salt, word32 sz);
 WOLFSSL_API
 int wc_ecc_ctx_set_info(ecEncCtx* ctx, const byte* info, int sz);