1 files changed, 43 insertions, 33 deletions

diff --git a/sshbuf.c b/sshbuf.c
index 91cbd067c..cbf7ed4a4 100644
--- a/sshbuf.c
+++ b/sshbuf.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: sshbuf.c,v 1.7 2016/09/12 01:22:38 deraadt Exp $      */
+/*      $OpenBSD: sshbuf.c,v 1.8 2016/11/25 23:22:04 djm Exp $  */
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -316,16 +316,13 @@ sshbuf_check_reserve(const struct sshbuf *buf, size_t len)
 }
 
 int
-sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp)
+sshbuf_allocate(struct sshbuf *buf, size_t len)
 {
         size_t rlen, need;
         u_char *dp;
         int r;
 
-        if (dpp != NULL)
-                *dpp = NULL;
-
-        SSHBUF_DBG(("reserve buf = %p len = %zu", buf, len));
+        SSHBUF_DBG(("allocate buf = %p len = %zu", buf, len));
         if ((r = sshbuf_check_reserve(buf, len)) != 0)
                 return r;
         /*
@@ -333,36 +330,49 @@ sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp)
          * then pack the buffer, zeroing buf->off.
          */
         sshbuf_maybe_pack(buf, buf->size + len > buf->max_size);
-        SSHBUF_TELL("reserve");
-        if (len + buf->size > buf->alloc) {
-                /*
-                 * Prefer to alloc in SSHBUF_SIZE_INC units, but
-                 * allocate less if doing so would overflow max_size.
-                 */
-                need = len + buf->size - buf->alloc;
-                rlen = ROUNDUP(buf->alloc + need, SSHBUF_SIZE_INC);
-                SSHBUF_DBG(("need %zu initial rlen %zu", need, rlen));
-                if (rlen > buf->max_size)
-                        rlen = buf->alloc + need;
-                SSHBUF_DBG(("adjusted rlen %zu", rlen));
-                if ((dp = realloc(buf->d, rlen)) == NULL) {
-                        SSHBUF_DBG(("realloc fail"));
-                        if (dpp != NULL)
-                                *dpp = NULL;
-                        return SSH_ERR_ALLOC_FAIL;
-                }
-                buf->alloc = rlen;
-                buf->cd = buf->d = dp;
-                if ((r = sshbuf_check_reserve(buf, len)) < 0) {
-                        /* shouldn't fail */
-                        if (dpp != NULL)
-                                *dpp = NULL;
-                        return r;
-                }
+        SSHBUF_TELL("allocate");
+        if (len + buf->size <= buf->alloc)
+                return 0; /* already have it. */
+
+        /*
+         * Prefer to alloc in SSHBUF_SIZE_INC units, but
+         * allocate less if doing so would overflow max_size.
+         */
+        need = len + buf->size - buf->alloc;
+        rlen = ROUNDUP(buf->alloc + need, SSHBUF_SIZE_INC);
+        SSHBUF_DBG(("need %zu initial rlen %zu", need, rlen));
+        if (rlen > buf->max_size)
+                rlen = buf->alloc + need;
+        SSHBUF_DBG(("adjusted rlen %zu", rlen));
+        if ((dp = realloc(buf->d, rlen)) == NULL) {
+                SSHBUF_DBG(("realloc fail"));
+                return SSH_ERR_ALLOC_FAIL;
+        }
+        buf->alloc = rlen;
+        buf->cd = buf->d = dp;
+        if ((r = sshbuf_check_reserve(buf, len)) < 0) {
+                /* shouldn't fail */
+                return r;
         }
+        SSHBUF_TELL("done");
+        return 0;
+}
+
+int
+sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp)
+{
+        u_char *dp;
+        int r;
+
+        if (dpp != NULL)
+                *dpp = NULL;
+
+        SSHBUF_DBG(("reserve buf = %p len = %zu", buf, len));
+        if ((r = sshbuf_allocate(buf, len)) != 0)
+                return r;
+
         dp = buf->d + buf->size;
         buf->size += len;
-        SSHBUF_TELL("done");
         if (dpp != NULL)
                 *dpp = dp;
         return 0;