1 files changed, 41 insertions, 0 deletions

diff --git a/src/lib/libcrypto/bn/divtest.c b/src/lib/libcrypto/bn/divtest.c
new file mode 100644
index 0000000000..d3fc688f33
--- /dev/null
+++ b/src/lib/libcrypto/bn/divtest.c
@@ -0,0 +1,41 @@
+#include <openssl/bn.h>
+#include <openssl/rand.h>
+
+static int Rand(n)
+{
+    unsigned char x[2];
+    RAND_pseudo_bytes(x,2);
+    return (x[0] + 2*x[1]);
+}
+
+static 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");
+    fflush(stdout);
+}
+
+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_pseudo_rand(a,Rand(),0,0);
+        BN_pseudo_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);
+    }
+}