Abdelilah Essiari <aes@george.lbl.gov> reports that for very small

[openssl.git] / crypto / bn / bn_gcd.c

diff --git a/crypto/bn/bn_gcd.c b/crypto/bn/bn_gcd.c
index 64a76f4498965b0e912eece66863edead0e46d27..398207196be841403cc5c2b3caf36e9c7cb8e9a4 100644 (file)
--- a/crypto/bn/bn_gcd.c
+++ b/crypto/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);
        }