avoid SIGSEGV

Submitted by: Nils Larsch, Douglas Stebila

diff --git a/crypto/bn/bn_gf2m.c b/crypto/bn/bn_gf2m.c
index c969685c87467a0b18d4c2580009f1fa77bd72e6..8bd17e0e7c9acc4094856232c0567f2c00f46242 100644 (file)
--- a/crypto/bn/bn_gf2m.c
+++ b/crypto/bn/bn_gf2m.c
@@ -316,10 +316,10 @@ int BN_GF2m_mod_arr(BIGNUM *r, const BIGNUM *a, const unsigned int p[])
        int n, dN, d0, d1;
        BN_ULONG zz, *z;
        
-       /* Since the algorithm does reduction in place, if a == r, copy the
+       /* Since the algorithm does reduction in the r value, if a != r, copy the
         * contents of a into r so we can do reduction in r. 
         */
-       if ((a != NULL) && (a->d != r->d))
+       if (a != r)
                {
                if (!bn_wexpand(r, a->top)) return 0;
                for (j = 0; j < a->top; j++)
@@ -427,7 +427,7 @@ int BN_GF2m_mod_mul_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const unsig
        BN_CTX_start(ctx);
        if ((s = BN_CTX_get(ctx)) == NULL) goto err;
        
-       zlen = a->top + b->top;
+       zlen = a->top + b->top + 4;
        if (!bn_wexpand(s, zlen)) goto err;
        s->top = zlen;