From d983bbe860461b599f124bc3b178b42a38866d9d Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Wed, 25 Jun 2014 21:29:55 -0700
Subject: [PATCH] zerocopy crypto_box_easy() and crypto_box_open_easy()

---
 src/libsodium/crypto_box/crypto_box_easy.c | 88 ++++------------------
 1 file changed, 15 insertions(+), 73 deletions(-)

diff --git a/src/libsodium/crypto_box/crypto_box_easy.c b/src/libsodium/crypto_box/crypto_box_easy.c
index ecc33b66..a01b4961 100644
--- a/src/libsodium/crypto_box/crypto_box_easy.c
+++ b/src/libsodium/crypto_box/crypto_box_easy.c
@@ -1,11 +1,6 @@
 
-#include <assert.h>
-#include <limits.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-
 #include "crypto_box.h"
+#include "crypto_secretbox.h"
 #include "utils.h"
 
 int
@@ -13,42 +8,16 @@ crypto_box_easy(unsigned char *c, const unsigned char *m,
                 unsigned long long mlen, const unsigned char *n,
                 const unsigned char *pk, const unsigned char *sk)
 {
-    unsigned char *c_boxed;
-    unsigned char *m_boxed;
-    size_t         c_boxed_len;
-    size_t         m_boxed_len;
-    int            rc;
+    unsigned char k[crypto_box_BEFORENMBYTES];
+    int           ret;
 
-    if (mlen > SIZE_MAX - crypto_box_ZEROBYTES) {
-        return -1;
-    }
-    (void) sizeof(char[crypto_box_ZEROBYTES >=
-                       crypto_box_BOXZEROBYTES ? 1 : -1]);
-    m_boxed_len = (size_t) mlen + crypto_box_ZEROBYTES;
-    if ((m_boxed = (unsigned char *) malloc((size_t) m_boxed_len)) == NULL) {
-        return -1;
-    }
-    c_boxed_len = (size_t) mlen + crypto_box_ZEROBYTES;
-    if ((c_boxed = (unsigned char *) malloc(c_boxed_len)) == NULL) {
-        free(m_boxed);
-        return -1;
-    }
-    memset(m_boxed, 0, crypto_box_ZEROBYTES);
-    sodium_mlock(m_boxed, m_boxed_len);
-    memcpy(m_boxed + crypto_box_ZEROBYTES, m, mlen);
-    rc = crypto_box(c_boxed, m_boxed, m_boxed_len, n, pk, sk);
-    sodium_munlock(m_boxed, m_boxed_len);
-    free(m_boxed);
-    if (rc != 0) {
-        free(c_boxed);
-        return -1;
-    }
-    assert(m_boxed_len - crypto_box_BOXZEROBYTES ==
-           mlen + crypto_box_MACBYTES);
-    memcpy(c, c_boxed + crypto_box_BOXZEROBYTES, mlen + crypto_box_MACBYTES);
-    free(c_boxed);
+    (void) sizeof(int[crypto_box_BEFORENMBYTES >=
+                      crypto_secretbox_KEYBYTES ? 1 : -1]);
+    crypto_box_beforenm(k, pk, sk);
+    ret = crypto_secretbox_easy(c, m, mlen, n, k);
+    sodium_memzero(k, sizeof k);
 
-    return 0;
+    return ret;
 }
 
 int
@@ -56,39 +25,12 @@ crypto_box_open_easy(unsigned char *m, const unsigned char *c,
                      unsigned long long clen, const unsigned char *n,
                      const unsigned char *pk, const unsigned char *sk)
 {
-    unsigned char *c_boxed;
-    unsigned char *m_boxed;
-    size_t         c_boxed_len;
-    size_t         m_boxed_len;
-    int            rc;
+    unsigned char k[crypto_box_BEFORENMBYTES];
+    int           ret;
 
-    if (clen < crypto_box_MACBYTES ||
-        clen > SIZE_MAX - crypto_box_BOXZEROBYTES) {
-        return -1;
-    }
-    c_boxed_len = clen + crypto_box_BOXZEROBYTES;
-    if ((c_boxed = (unsigned char *) malloc(c_boxed_len)) == NULL) {
-        return -1;
-    }
-    memset(c_boxed, 0, crypto_box_BOXZEROBYTES);
-    memcpy(c_boxed + crypto_box_BOXZEROBYTES, c, clen);
-    m_boxed_len = crypto_box_ZEROBYTES + (clen - crypto_box_MACBYTES);
-    if ((m_boxed = (unsigned char *) malloc(m_boxed_len)) == NULL) {
-        free(c_boxed);
-        return -1;
-    }
-    sodium_mlock(m_boxed, m_boxed_len);
-    rc = crypto_box_open(m_boxed, c_boxed,
-                         (unsigned long long) c_boxed_len, n, pk, sk);
-    free(c_boxed);
-    if (rc != 0) {
-        sodium_munlock(m_boxed, m_boxed_len);
-        free(m_boxed);
-        return -1;
-    }
-    memcpy(m, m_boxed + crypto_box_ZEROBYTES, clen - crypto_box_MACBYTES);
-    sodium_munlock(m_boxed, m_boxed_len);
-    free(m_boxed);
+    crypto_box_beforenm(k, pk, sk);
+    ret = crypto_secretbox_open_easy(m, c, clen, n, k);
+    sodium_memzero(k, sizeof k);
 
-    return 0;
+    return ret;
 }