Add support for building tinc with MSVC

[tinc] / src / nolegacy / prf.c

diff --git a/src/nolegacy/prf.c b/src/nolegacy/prf.c
index 1e5bb9f..5db6430 100644 (file)
--- a/src/nolegacy/prf.c
+++ b/src/nolegacy/prf.c
@@ -32,7 +32,8 @@ static const size_t mdlen = 64;
 static const size_t blklen = 128;
 
 static bool hmac_sha512(const uint8_t *key, size_t keylen, const uint8_t *msg, size_t msglen, uint8_t *out) {
-       uint8_t tmp[blklen + mdlen];
+       const size_t tmplen = blklen + mdlen;
+       uint8_t *tmp = alloca(tmplen);
        sha512_context md;
 
        if(keylen <= blklen) {
@@ -69,7 +70,7 @@ static bool hmac_sha512(const uint8_t *key, size_t keylen, const uint8_t *msg, s
        // opad
        memxor(tmp, 0x36 ^ 0x5c, blklen);
 
-       if(sha512(tmp, sizeof(tmp), out) != 0) {
+       if(sha512(tmp, tmplen, out) != 0) {
                return false;
        }
 
@@ -86,28 +87,29 @@ bool prf(const uint8_t *secret, size_t secretlen, uint8_t *seed, size_t seedlen,
           It consists of the previous HMAC result plus the seed.
         */
 
-       uint8_t data[mdlen + seedlen];
+       const size_t datalen = mdlen + seedlen;
+       uint8_t *data = alloca(datalen);
        memset(data, 0, mdlen);
        memcpy(data + mdlen, seed, seedlen);
 
-       uint8_t hash[mdlen];
+       uint8_t *hash = alloca(mdlen);
 
        while(outlen > 0) {
                /* Inner HMAC */
-               if(!hmac_sha512(secret, secretlen, data, sizeof(data), data)) {
+               if(!hmac_sha512(secret, secretlen, data, datalen, data)) {
                        return false;
                }
 
                /* Outer HMAC */
                if(outlen >= mdlen) {
-                       if(!hmac_sha512(secret, secretlen, data, sizeof(data), out)) {
+                       if(!hmac_sha512(secret, secretlen, data, datalen, out)) {
                                return false;
                        }
 
                        out += mdlen;
                        outlen -= mdlen;
                } else {
-                       if(!hmac_sha512(secret, secretlen, data, sizeof(data), hash)) {
+                       if(!hmac_sha512(secret, secretlen, data, datalen, hash)) {
                                return false;
                        }