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

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--)
                {

diff --git a/doc/crypto/BN_add_word.pod b/doc/crypto/BN_add_word.pod
index 94244adea4cd973b6e17bce818c6c164f0b778e7..70667d2893458ba8637656b28d669bd1531815aa 100644 (file)
--- a/doc/crypto/BN_add_word.pod
+++ b/doc/crypto/BN_add_word.pod
@@ -29,11 +29,11 @@ BN_add_word() adds B<w> to B<a> (C<a+=w>).
 
 BN_sub_word() subtracts B<w> from B<a> (C<a-=w>).
 
-BN_mul_word() multiplies B<a> and B<w> (C<a*=b>).
+BN_mul_word() multiplies B<a> and B<w> (C<a*=w>).
 
 BN_div_word() divides B<a> by B<w> (C<a/=w>) and returns the remainder.
 
-BN_mod_word() returns the remainder of B<a> divided by B<w> (C<a%m>).
+BN_mod_word() returns the remainder of B<a> divided by B<w> (C<a%w>).
 
 For BN_div_word() and BN_mod_word(), B<w> must not be 0.
 
@@ -42,7 +42,8 @@ For BN_div_word() and BN_mod_word(), B<w> must not be 0.
 BN_add_word(), BN_sub_word() and BN_mul_word() return 1 for success, 0
 on error. The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
 
-BN_mod_word() and BN_div_word() return B<a>%B<w>.
+BN_mod_word() and BN_div_word() return B<a>%B<w> on success and
+B<(BN_ULONG)-1> if an error occurred.
 
 =head1 SEE ALSO
 
@@ -54,4 +55,7 @@ BN_add_word() and BN_mod_word() are available in all versions of
 SSLeay and OpenSSL. BN_div_word() was added in SSLeay 0.8, and
 BN_sub_word() and BN_mul_word() in SSLeay 0.9.0.
 
+Before 0.9.8a the return value for BN_div_word() and BN_mod_word()
+in case of an error was 0.
+
 =cut