Remove useless sodium_memzero, add one that makes sense

Author: jedisct1

src/libsodium/crypto_box/crypto_box_seal.c

@@ -37,8 +37,6 @@ crypto_box_seal(unsigned char *c, const unsigned char *m,
                           nonce, pk, esk);
     memcpy(c, epk, crypto_box_PUBLICKEYBYTES);
     sodium_memzero(esk, sizeof esk);
-    sodium_memzero(epk, sizeof epk);
-    sodium_memzero(nonce, sizeof nonce);
 
     return ret;
 }

src/libsodium/crypto_box/curve25519xchacha20poly1305/box_curve25519xchacha20poly1305.c

@@ -48,7 +48,10 @@ crypto_box_curve25519xchacha20poly1305_beforenm(unsigned char *k,
     if (crypto_scalarmult_curve25519(s, sk, pk) != 0) {
         return -1;
     }
-    return crypto_core_hchacha20(k, zero, s, NULL);
+    crypto_core_hchacha20(k, zero, s, NULL);
+    sodium_memzero(s, sizeof s);
+
+    return 0;
 }
 
 int

src/libsodium/crypto_box/curve25519xchacha20poly1305/box_seal_curve25519xchacha20poly1305.c

@@ -44,8 +44,6 @@ crypto_box_curve25519xchacha20poly1305_seal(unsigned char *c, const unsigned cha
          nonce, pk, esk);
     memcpy(c, epk, crypto_box_curve25519xchacha20poly1305_PUBLICKEYBYTES);
     sodium_memzero(esk, sizeof esk);
-    sodium_memzero(epk, sizeof epk);
-    sodium_memzero(nonce, sizeof nonce);
 
     return ret;
 }

src/libsodium/crypto_box/curve25519xsalsa20poly1305/box_curve25519xsalsa20poly1305.c

@@ -42,7 +42,10 @@ crypto_box_curve25519xsalsa20poly1305_beforenm(unsigned char *k,
     if (crypto_scalarmult_curve25519(s, sk, pk) != 0) {
         return -1;
     }
-    return crypto_core_hsalsa20(k, zero, s, NULL);
+    crypto_core_hsalsa20(k, zero, s, NULL);
+    sodium_memzero(s, sizeof s);
+
+    return 0;
 }
 
 int