1 files changed, 17 insertions, 11 deletions

diff --git a/src/lib/libcrypto/bn/bn_gcd.c b/src/lib/libcrypto/bn/bn_gcd.c
index 64a76f4498..398207196b 100644
--- a/src/lib/libcrypto/bn/bn_gcd.c
+++ b/src/lib/libcrypto/bn/bn_gcd.c
@@ -61,6 +61,7 @@
 #include "bn_lcl.h"
 
 static BIGNUM *euclid(BIGNUM *a, BIGNUM *b);
+
 int BN_gcd(BIGNUM *r, BIGNUM *in_a, BIGNUM *in_b, BN_CTX *ctx)
         {
         BIGNUM *a,*b,*t;
@@ -69,8 +70,10 @@ int BN_gcd(BIGNUM *r, BIGNUM *in_a, BIGNUM *in_b, BN_CTX *ctx)
         bn_check_top(in_a);
         bn_check_top(in_b);
 
-        a= &(ctx->bn[ctx->tos]);
-        b= &(ctx->bn[ctx->tos+1]);
+        BN_CTX_start(ctx);
+        a = BN_CTX_get(ctx);
+        b = BN_CTX_get(ctx);
+        if (a == NULL || b == NULL) goto err;
 
         if (BN_copy(a,in_a) == NULL) goto err;
         if (BN_copy(b,in_b) == NULL) goto err;
@@ -82,6 +85,7 @@ int BN_gcd(BIGNUM *r, BIGNUM *in_a, BIGNUM *in_b, BN_CTX *ctx)
         if (BN_copy(r,t) == NULL) goto err;
         ret=1;
 err:
+        BN_CTX_end(ctx);
         return(ret);
         }
 
@@ -142,20 +146,22 @@ err:
 /* solves ax == 1 (mod n) */
 BIGNUM *BN_mod_inverse(BIGNUM *in, BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
         {
-        BIGNUM *A,*B,*X,*Y,*M,*D,*R;
+        BIGNUM *A,*B,*X,*Y,*M,*D,*R=NULL;
         BIGNUM *T,*ret=NULL;
         int sign;
 
         bn_check_top(a);
         bn_check_top(n);
 
-        A= &(ctx->bn[ctx->tos]);
-        B= &(ctx->bn[ctx->tos+1]);
-        X= &(ctx->bn[ctx->tos+2]);
-        D= &(ctx->bn[ctx->tos+3]);
-        M= &(ctx->bn[ctx->tos+4]);
-        Y= &(ctx->bn[ctx->tos+5]);
-        ctx->tos+=6;
+        BN_CTX_start(ctx);
+        A = BN_CTX_get(ctx);
+        B = BN_CTX_get(ctx);
+        X = BN_CTX_get(ctx);
+        D = BN_CTX_get(ctx);
+        M = BN_CTX_get(ctx);
+        Y = BN_CTX_get(ctx);
+        if (Y == NULL) goto err;
+
         if (in == NULL)
                 R=BN_new();
         else
@@ -198,7 +204,7 @@ BIGNUM *BN_mod_inverse(BIGNUM *in, BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
         ret=R;
 err:
         if ((ret == NULL) && (in == NULL)) BN_free(R);
-        ctx->tos-=6;
+        BN_CTX_end(ctx);
         return(ret);
         }