fix BN_mod_word and give a more reasonable return value if an error occurred

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

diff --git a/crypto/bn/bn_word.c b/crypto/bn/bn_word.c
index bc5905fef4279e644ae4f2090ad6e7a5f4bd0f8d..ee7b87c45ccd38839db6261ed81c2d87b9e881b5 100644 (file)
--- a/crypto/bn/bn_word.c
+++ b/crypto/bn/bn_word.c
@@ -69,6 +69,9 @@ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
 #endif
        int i;
 
+       if (w == 0)
+               return (BN_ULONG)-1;
+
        bn_check_top(a);
        w&=BN_MASK2;
        for (i=a->top-1; i>=0; i--)
@@ -94,7 +97,7 @@ BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
 
        if (!w)
                /* actually this an error (division by zero) */
-               return 0;
+               return (BN_ULONG)-1;
        if (a->top == 0)
                return 0;
 
@@ -102,7 +105,7 @@ BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
        j = BN_BITS2 - BN_num_bits_word(w);
        w <<= j;
        if (!BN_lshift(a, a, j))
-               return 0;
+               return (BN_ULONG)-1;
 
        for (i=a->top-1; i>=0; i--)
                {