tolerate broken CMS/PKCS7 implementations using signature OID instead of digest

[oweals/openssl.git] / crypto / bn / bn_div.c

diff --git a/crypto/bn/bn_div.c b/crypto/bn/bn_div.c
index 8655eb118e6b4775f2097f02c4f2b79b23b2a7f3..5ea0d6510f8734b0d46537849bfe70c96374adaf 100644 (file)
--- a/crypto/bn/bn_div.c
+++ b/crypto/bn/bn_div.c
@@ -187,6 +187,17 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
        BN_ULONG d0,d1;
        int num_n,div_n;
 
+       /* Invalid zero-padding would have particularly bad consequences
+        * in the case of 'num', so don't just rely on bn_check_top() for this one
+        * (bn_check_top() works only for BN_DEBUG builds) */
+       if (num->top > 0 && num->d[num->top - 1] == 0)
+               {
+               BNerr(BN_F_BN_DIV,BN_R_NOT_INITIALIZED);
+               return 0;
+               }
+
+       bn_check_top(num);
+
        if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0))
                {
                return BN_div_no_branch(dv, rm, num, divisor, ctx);
@@ -194,7 +205,7 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
 
        bn_check_top(dv);
        bn_check_top(rm);
-       bn_check_top(num);
+       /* bn_check_top(num); */ /* 'num' has been checked already */
        bn_check_top(divisor);
 
        if (BN_is_zero(divisor))
@@ -218,7 +229,8 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
        if (dv == NULL)
                res=BN_CTX_get(ctx);
        else    res=dv;
-       if (sdiv == NULL || res == NULL) goto err;
+       if (sdiv == NULL || res == NULL || tmp == NULL || snum == NULL)
+               goto err;
 
        /* First we normalise the numbers */
        norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
@@ -419,7 +431,7 @@ static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
 
        bn_check_top(dv);
        bn_check_top(rm);
-       bn_check_top(num);
+       /* bn_check_top(num); */ /* 'num' has been checked in BN_div() */
        bn_check_top(divisor);
 
        if (BN_is_zero(divisor))