- (djm) OpenBSD CVS Sync

   - markus@cvs.openbsd.org 2002/06/26 08:53:12
     [bufaux.c]
     limit size of BNs to 8KB; ok provos/deraadt

2 files changed, 13 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index 55075c806..8fa522ffb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,10 @@
  - (stevesk) [README.privsep] more for sshd pseudo-account.
  - (tim) [contrib/caldera/openssh.spec] add support for privsep
  - (djm) setlogin needs pgid==pid on BSD/OS; from itojun@
+ - (djm) OpenBSD CVS Sync
+   - markus@cvs.openbsd.org 2002/06/26 08:53:12
+     [bufaux.c]
+     limit size of BNs to 8KB; ok provos/deraadt
 
 20020625
  - (stevesk) [INSTALL acconfig.h configure.ac defines.h] remove --with-rsh
@@ -1134,4 +1138,4 @@
  - (stevesk) entropy.c: typo in debug message
  - (djm) ssh-keygen -i needs seeded RNG; report from markus@
 
-$Id: ChangeLog,v 1.2289 2002/06/26 09:12:59 djm Exp $
+$Id: ChangeLog,v 1.2290 2002/06/26 09:14:08 djm Exp $
diff --git a/bufaux.c b/bufaux.c
index 80abe890b..d3dc674ce 100644
--- a/bufaux.c
+++ b/bufaux.c
@@ -37,7 +37,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: bufaux.c,v 1.26 2002/06/23 09:46:51 deraadt Exp $");
+RCSID("$OpenBSD: bufaux.c,v 1.27 2002/06/26 08:53:12 markus Exp $");
 
 #include <openssl/bn.h>
 #include "bufaux.h"
@@ -88,6 +88,8 @@ buffer_get_bignum(Buffer *buffer, BIGNUM *value)
         bits = GET_16BIT(buf);
         /* Compute the number of binary bytes that follow. */
         bytes = (bits + 7) / 8;
+        if (bytes > 8 * 1024)
+                fatal("buffer_get_bignum: cannot handle BN of size %d", bytes);
         if (buffer_len(buffer) < bytes)
                 fatal("buffer_get_bignum: input buffer too small");
         bin = buffer_ptr(buffer);
@@ -129,13 +131,15 @@ buffer_put_bignum2(Buffer *buffer, BIGNUM *value)
         xfree(buf);
 }
 
+/* XXX does not handle negative BNs */
 void
 buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
 {
-        /**XXX should be two's-complement */
-        int len;
-        u_char *bin = buffer_get_string(buffer, (u_int *)&len);
+        u_int len;
+        u_char *bin = buffer_get_string(buffer, &len);
 
+        if (len > 8 * 1024)
+                fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
         BN_bin2bn(bin, len, value);
         xfree(bin);
 }