- markus@cvs.openbsd.org 2004/02/23 15:12:46

     [bufaux.c]
     encode 0 correctly in buffer_put_bignum2; noted by Mikulas Patocka
     and drop support for negative BNs; ok otto@

2 files changed, 23 insertions, 18 deletions

diff --git a/ChangeLog b/ChangeLog
index 5628b943f..ce4550384 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,10 @@
    - markus@cvs.openbsd.org 2004/02/23 12:02:33
      [sshd.c]
      backout revision 1.279; set listen socket to non-block; ok henning.
+   - markus@cvs.openbsd.org 2004/02/23 15:12:46
+     [bufaux.c]
+     encode 0 correctly in buffer_put_bignum2; noted by Mikulas Patocka
+     and drop support for negative BNs; ok otto@
 
 20040223
  - (dtucker) [session.c] Bug #789: Only make setcred call for !privsep in the
@@ -1909,4 +1913,4 @@
  - Fix sshd BindAddress and -b options for systems using fake-getaddrinfo.
    Report from murple@murple.net, diagnosis from dtucker@zip.com.au
 
-$Id: ChangeLog,v 1.3245 2004/02/23 22:20:29 dtucker Exp $
+$Id: ChangeLog,v 1.3246 2004/02/23 22:21:41 dtucker Exp $
diff --git a/bufaux.c b/bufaux.c
index 339d74435..bf148316d 100644
--- a/bufaux.c
+++ b/bufaux.c
@@ -37,7 +37,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: bufaux.c,v 1.31 2003/11/10 16:23:41 jakob Exp $");
+RCSID("$OpenBSD: bufaux.c,v 1.32 2004/02/23 15:12:46 markus Exp $");
 
 #include <openssl/bn.h>
 #include "bufaux.h"
@@ -103,46 +103,47 @@ buffer_get_bignum(Buffer *buffer, BIGNUM *value)
 void
 buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
 {
-        u_int bytes = BN_num_bytes(value) + 1;
-        u_char *buf = xmalloc(bytes);
+        u_int bytes;
+        u_char *buf;
         int oi;
         u_int hasnohigh = 0;
 
+        if (BN_is_zero(value)) {
+                buffer_put_int(buffer, 0);
+                return;
+        }
+        if (value->neg)
+                fatal("buffer_put_bignum2: negative numbers not supported");
+        bytes = BN_num_bytes(value) + 1; /* extra padding byte */
+        if (bytes < 2)
+                fatal("buffer_put_bignum2: BN too small");
+        buf = xmalloc(bytes);
         buf[0] = '\0';
         /* Get the value of in binary */
         oi = BN_bn2bin(value, buf+1);
         if (oi != bytes-1)
-                fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
-                    oi, bytes);
+                fatal("buffer_put_bignum2: BN_bn2bin() failed: "
+                    "oi %d != bin_size %d", oi, bytes);
         hasnohigh = (buf[1] & 0x80) ? 0 : 1;
-        if (value->neg) {
-                /**XXX should be two's-complement */
-                int i, carry;
-                u_char *uc = buf;
-                logit("negativ!");
-                for (i = bytes-1, carry = 1; i>=0; i--) {
-                        uc[i] ^= 0xff;
-                        if (carry)
-                                carry = !++uc[i];
-                }
-        }
         buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
         memset(buf, 0, bytes);
         xfree(buf);
 }
 
-/* XXX does not handle negative BNs */
 void
 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
 {
         u_int len;
         u_char *bin = buffer_get_string(buffer, &len);
 
+        if (len > 0 && (bin[0] & 0x80))
+                fatal("buffer_get_bignum2: negative numbers not supported");
         if (len > 8 * 1024)
                 fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
         BN_bin2bn(bin, len, value);
         xfree(bin);
 }
+
 /*
  * Returns integers from the buffer (msb first).
  */