Align math with t1_enc.c

suggested by jsing on review

diff --git a/lib/libcrypto/kdf/tls1_prf.c b/lib/libcrypto/kdf/tls1_prf.c
index e28962d..afc629b 100644 (file)
--- a/lib/libcrypto/kdf/tls1_prf.c
+++ b/lib/libcrypto/kdf/tls1_prf.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tls1_prf.c,v 1.34 2024/07/09 17:35:55 tb Exp $ */
+/*     $OpenBSD: tls1_prf.c,v 1.35 2024/07/09 17:44:18 tb Exp $ */
 /*
  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
  * 2016.
@@ -265,23 +265,25 @@ tls1_prf_alg(const EVP_MD *md,
     unsigned char *out, size_t out_len)
 {
        unsigned char *tmp;
+       size_t half_len;
        size_t i;
 
        if (EVP_MD_type(md) != NID_md5_sha1)
                return tls1_prf_P_hash(md, secret, secret_len, seed, seed_len,
                    out, out_len);
 
-       if (!tls1_prf_P_hash(EVP_md5(),
-           secret, secret_len / 2 + (secret_len & 1),
-           seed, seed_len, out, out_len))
+       half_len = secret_len - secret_len / 2;
+       if (!tls1_prf_P_hash(EVP_md5(), secret, half_len, seed, seed_len,
+           out, out_len))
                return 0;
 
        if ((tmp = calloc(1, out_len)) == NULL) {
                KDFerror(ERR_R_MALLOC_FAILURE);
                return 0;
        }
-       if (!tls1_prf_P_hash(EVP_sha1(), secret + secret_len / 2,
-           secret_len / 2 + (secret_len & 1), seed, seed_len, tmp, out_len)) {
+       secret += secret_len - half_len;
+       if (!tls1_prf_P_hash(EVP_sha1(), secret, half_len, seed, seed_len,
+           tmp, out_len)) {
                freezero(tmp, out_len);
                return 0;
        }