From fe772376ec29028a761eb5ad08a635f7b712d82f Mon Sep 17 00:00:00 2001
From: =?utf8?q?Bodo=20M=C3=B6ller?= <bodo@openssl.org>
Date: Sun, 3 Dec 2000 09:37:15 +0000
Subject: [PATCH] Don't allow BIGNUMs to become so large that computations with
 dmax might overflow.

---
 crypto/bn/bn.h     | 1 +
 crypto/bn/bn_err.c | 1 +
 crypto/bn/bn_lib.c | 6 ++++++
 3 files changed, 8 insertions(+)

diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 3f6864fcf3..f464981929 100644
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -505,6 +505,7 @@ BN_ULONG bn_sub_words(BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,int num);
 #define BN_R_INVALID_LENGTH				 106
 #define BN_R_NOT_INITIALIZED				 107
 #define BN_R_NO_INVERSE					 108
+#define BN_R_TOO_LARGE					 114
 #define BN_R_TOO_MANY_TEMPORARY_VARIABLES		 109
 
 #ifdef  __cplusplus
diff --git a/crypto/bn/bn_err.c b/crypto/bn/bn_err.c
index 86550c4c21..673a994996 100644
--- a/crypto/bn/bn_err.c
+++ b/crypto/bn/bn_err.c
@@ -99,6 +99,7 @@ static ERR_STRING_DATA BN_str_reasons[]=
 {BN_R_INVALID_LENGTH                     ,"invalid length"},
 {BN_R_NOT_INITIALIZED                    ,"not initialized"},
 {BN_R_NO_INVERSE                         ,"no inverse"},
+{BN_R_TOO_LARGE                          ,"too large"},
 {BN_R_TOO_MANY_TEMPORARY_VARIABLES       ,"too many temporary variables"},
 {0,NULL}
 	};
diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c
index b6b0ce4b3c..c32958c101 100644
--- a/crypto/bn/bn_lib.c
+++ b/crypto/bn/bn_lib.c
@@ -319,6 +319,12 @@ BIGNUM *bn_expand2(BIGNUM *b, int words)
 
 	if (words > b->dmax)
 		{
+		if (words > (INT_MAX/(4*BN_BITS2)))
+			{
+			BNerr(BN_F_BN_EXPAND2,BN_R_TOO_LARGE);
+			return NULL;
+			}
+			
 		bn_check_top(b);	
 		if (BN_get_flags(b,BN_FLG_STATIC_DATA))
 			{
-- 
2.25.1