Test the division functions.

Apparently BN_div_recp reports an error for small divisors
(1,2,4,8,40).

I haven't got mismatches so far. If you can, please run the test
program for a few days (nohup divtest >out& or something), and if it
reports a mismatch, post the output.

1 files changed, 39 insertions, 0 deletions

diff --git a/crypto/bn/divtest.c b/crypto/bn/divtest.c
new file mode 100644
index 0000000000..bb301680c0
--- /dev/null
+++ b/crypto/bn/divtest.c
@@ -0,0 +1,39 @@
+#include <openssl/bn.h>
+
+int rand(n)
+{
+    unsigned char x[2];
+    RAND_bytes(&x,2);
+    return (x[0] + 2*x[1]);
+}
+
+void bug(char *m, BIGNUM *a, BIGNUM *b)
+{
+    printf("%s!\na=",m);
+    BN_print_fp(stdout, a);
+    printf("\nb=");
+    BN_print_fp(stdout, b);
+    printf("\n");
+}
+
+main()
+{
+    BIGNUM *a=BN_new(), *b=BN_new(), *c=BN_new(), *d=BN_new(),
+	*C=BN_new(), *D=BN_new();
+    BN_RECP_CTX *recp=BN_RECP_CTX_new();
+    BN_CTX *ctx=BN_CTX_new();
+
+    for(;;) {
+	BN_rand(a,rand(),0,0);
+	BN_rand(b,rand(),0,0);
+	if (BN_is_zero(b)) continue;
+
+	BN_RECP_CTX_set(recp,b,ctx);
+	if (BN_div(C,D,a,b,ctx) != 1)
+	    bug("BN_div failed",a,b);
+	if (BN_div_recp(c,d,a,recp,ctx) != 1)
+	    bug("BN_div_recp failed",a,b);
+	else if (BN_cmp(c,C) != 0 || BN_cmp(c,C) != 0)
+	    bug("mismatch",a,b);
+    }
+}