1 files changed, 30 insertions, 9 deletions

diff --git a/dh.c b/dh.c
index 044d869fb..78e230b9f 100644
--- a/dh.c
+++ b/dh.c
@@ -1,3 +1,4 @@
+/* $OpenBSD: dh.c,v 1.44 2006/11/07 13:02:07 markus Exp $ */
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
  *
@@ -23,17 +24,17 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: dh.c,v 1.31 2004/08/04 10:37:52 djm Exp $");
 
-#include "xmalloc.h"
+#include <sys/param.h>
 
 #include <openssl/bn.h>
 #include <openssl/dh.h>
-#include <openssl/evp.h>
 
-#include "buffer.h"
-#include "cipher.h"
-#include "kex.h"
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
 #include "dh.h"
 #include "pathnames.h"
 #include "log.h"
@@ -44,9 +45,11 @@ parse_prime(int linenum, char *line, struct dhgroup *dhg)
 {
         char *cp, *arg;
         char *strsize, *gen, *prime;
+        const char *errstr = NULL;
 
         cp = line;
-        arg = strdelim(&cp);
+        if ((arg = strdelim(&cp)) == NULL)
+                return 0;
         /* Ignore leading whitespace */
         if (*arg == '\0')
                 arg = strdelim(&cp);
@@ -67,7 +70,8 @@ parse_prime(int linenum, char *line, struct dhgroup *dhg)
                 goto fail;
         strsize = strsep(&cp, " "); /* size */
         if (cp == NULL || *strsize == '\0' ||
-            (dhg->size = atoi(strsize)) == 0)
+            (dhg->size = (u_int)strtonum(strsize, 0, 64*1024, &errstr)) == 0 ||
+            errstr)
                 goto fail;
         /* The whole group is one bit larger */
         dhg->size++;
@@ -178,19 +182,36 @@ dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
         int i;
         int n = BN_num_bits(dh_pub);
         int bits_set = 0;
+        BIGNUM *tmp;
 
         if (dh_pub->neg) {
                 logit("invalid public DH value: negativ");
                 return 0;
         }
+        if (BN_cmp(dh_pub, BN_value_one()) != 1) {      /* pub_exp <= 1 */
+                logit("invalid public DH value: <= 1");
+                return 0;
+        }
+
+        if ((tmp = BN_new()) == NULL)
+                return (-1);
+        if (!BN_sub(tmp, dh->p, BN_value_one()) ||
+            BN_cmp(dh_pub, tmp) != -1) {                /* pub_exp > p-2 */
+                BN_clear_free(tmp);
+                logit("invalid public DH value: >= p-1");
+                return 0;
+        }
+        BN_clear_free(tmp);
+
         for (i = 0; i <= n; i++)
                 if (BN_is_bit_set(dh_pub, i))
                         bits_set++;
         debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
 
         /* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
-        if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1))
+        if (bits_set > 1)
                 return 1;
+
         logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
         return 0;
 }