allow input-data pointer to be NULL

If we allow the length to be 0, we should also prepare for the case where
the user doesn't want to provide a valid input-data pointer.

Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>

Author: sjaeckel

src/pk/pkcs1/pkcs_1_oaep_encode.c

@@ -33,7 +33,7 @@ int pkcs_1_oaep_encode(const unsigned char *msg,    unsigned long msglen,
    unsigned long hLen, x, y, modulus_len;
    int           err;
 
-   LTC_ARGCHK(msg    != NULL);
+   LTC_ARGCHK((msglen == 0) || (msg != NULL));
    LTC_ARGCHK(out    != NULL);
    LTC_ARGCHK(outlen != NULL);
 
@@ -95,9 +95,11 @@ int pkcs_1_oaep_encode(const unsigned char *msg,    unsigned long msglen,
    /* 0x01 byte */
    DB[x++] = 0x01;
 
-   /* message (length = msglen) */
-   XMEMCPY(DB+x, msg, msglen);
-   x += msglen;
+   if (msglen != 0) {
+      /* message (length = msglen) */
+      XMEMCPY(DB+x, msg, msglen);
+      x += msglen;
+   }
 
    /* now choose a random seed */
    if (prng_descriptor[prng_idx].read(seed, hLen, prng) != hLen) {

src/pk/pkcs1/pkcs_1_v1_5_encode.c

@@ -35,6 +35,10 @@ int pkcs_1_v1_5_encode(const unsigned char *msg,
   unsigned char *ps;
   int result;
 
+  LTC_ARGCHK((msglen == 0) || (msg != NULL));
+  LTC_ARGCHK(out    != NULL);
+  LTC_ARGCHK(outlen != NULL);
+
   /* valid block_type? */
   if ((block_type != LTC_PKCS_1_EMSA) &&
       (block_type != LTC_PKCS_1_EME)) {
@@ -88,7 +92,9 @@ int pkcs_1_v1_5_encode(const unsigned char *msg,
   out[0]          = 0x00;
   out[1]          = (unsigned char)block_type;  /* block_type 1 or 2 */
   out[2 + ps_len] = 0x00;
-  XMEMCPY(&out[2 + ps_len + 1], msg, msglen);
+  if (msglen != 0) {
+    XMEMCPY(&out[2 + ps_len + 1], msg, msglen);
+  }
   *outlen = modulus_len;
 
   result  = CRYPT_OK;

src/pk/rsa/rsa_encrypt_key.c

@@ -34,7 +34,7 @@ int rsa_encrypt_key_ex(const unsigned char *in,       unsigned long  inlen,
   unsigned long modulus_bitlen, modulus_bytelen, x;
   int           err;
 
-  LTC_ARGCHK(in     != NULL);
+  LTC_ARGCHK((inlen == 0) || (in != NULL));
   LTC_ARGCHK(out    != NULL);
   LTC_ARGCHK(outlen != NULL);
   LTC_ARGCHK(key    != NULL);

tests/rsa_test.c

@@ -500,7 +500,7 @@ print_hex("q", tmp, len);
 
    /* encrypt the key (without lparam) */
    for (cnt = 0; cnt < 4; cnt++) {
-   for (rsa_msgsize = 1; rsa_msgsize <= 86; rsa_msgsize++) {
+   for (rsa_msgsize = 0; rsa_msgsize <= 86; rsa_msgsize++) {
       /* make a random key/msg */
       ENSURE(yarrow_read(in, rsa_msgsize, &yarrow_prng) == rsa_msgsize);
 
@@ -523,10 +523,10 @@ print_hex("q", tmp, len);
    }
 
    /* encrypt the key (with lparam) */
-   for (rsa_msgsize = 1; rsa_msgsize <= 86; rsa_msgsize++) {
+   for (rsa_msgsize = 0; rsa_msgsize <= 86; rsa_msgsize++) {
       len  = sizeof(out);
       len2 = rsa_msgsize;
-      DO(rsa_encrypt_key(in, rsa_msgsize, out, &len, lparam, sizeof(lparam), &yarrow_prng, prng_idx, hash_idx, &key));
+      DO(rsa_encrypt_key(rsa_msgsize ? in : NULL, rsa_msgsize, out, &len, lparam, sizeof(lparam), &yarrow_prng, prng_idx, hash_idx, &key));
       /* change a byte */
       out[8] ^= 1;
       SHOULD_FAIL(rsa_decrypt_key(out, len, tmp, &len2, lparam, sizeof(lparam), hash_idx, &stat2, &key));
@@ -542,7 +542,7 @@ print_hex("q", tmp, len);
    }
 
    /* encrypt the key PKCS #1 v1.5 (payload from 1 to 117 bytes) */
-   for (rsa_msgsize = 1; rsa_msgsize <= 117; rsa_msgsize++) {
+   for (rsa_msgsize = 0; rsa_msgsize <= 117; rsa_msgsize++) {
       len  = sizeof(out);
       len2 = rsa_msgsize;
       /* make a random key/msg */