Sorry about that.
I can put in the ernno for the error but the problem is CryptGenRandom does not
set the error number.
So it is either just print the value of GetLastError() or I use FormatMessage
function to get the text from that value. Like the following:
lib/entropy.c | 28 ++++++++++++++++++++++++++++
1 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/lib/entropy.c b/lib/entropy.c
index 02f56e0..0343d86 100644
--- a/lib/entropy.c
+++ b/lib/entropy.c
@@ -27,12 +27,16 @@
VLOG_DEFINE_THIS_MODULE(entropy);
static const char urandom[] = "/dev/urandom";
+#ifdef _WIN32
+#include <Wincrypt.h>
+#endif
/* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Returns
* 0 if successful, otherwise a positive errno value or EOF on error. */
int
get_entropy(void *buffer, size_t n)
{
+#ifndef _WIN32
size_t bytes_read;
int error;
int fd;
@@ -49,6 +53,30 @@ get_entropy(void *buffer, size_t n)
if (error) {
VLOG_ERR("%s: read error (%s)", urandom, ovs_retval_to_string(error));
}
+#else
+ int error = 0;
+ HCRYPTPROV crypt_prov = 0;
+ CryptAcquireContext(&crypt_prov, NULL, NULL, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT);
+
+ if (!CryptGenRandom(crypt_prov, n, buffer)) {
+ error = GetLastError();
+ LPVOID msg_buf;
+ FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER |
+ FORMAT_MESSAGE_FROM_SYSTEM |
+ FORMAT_MESSAGE_IGNORE_INSERTS,
+ NULL,
+ error,
+ 0,
+ (LPTSTR)&msg_buf,
+ 0,
+ NULL
+ );
+ VLOG_ERR("CryptGenRandom: read error (%s)", msg_buf);
+ LocalFree(msg_buf);
+ }
+
+ CryptReleaseContext(crypt_prov, 0);
+#endif
return error;
}
Would you like me to set up a helper function like ovs_retval_to_string (i.e.
ovs_getlasterror_to_string) or just leave it the way it is for the moment?
Kind Regards,
Alin.
________________________________________
From: Ben Pfaff [b...@nicira.com]
Sent: Saturday, December 14, 2013 7:22 PM
To: Alin Serdean
Cc: Gurucharan Shetty; dev@openvswitch.org
Subject: Re: [ovs-dev] [PATCH] windows pseudorandom number generator
On Sat, Dec 14, 2013 at 01:20:31AM +0000, Alin Serdean wrote:
> This patch is to add for secure pseudorandom number generator on windows.
>
> Signed-off-by: Alin Serdean <aserdean at cloudbasesolutions.com>
I'm pretty sure that GetLastError() doesn't return an errno value, but
this code tries to pass it to ovs_retval_to_string() and return it to a
caller expecting an errno. Can you do better than that? Thanks.
> + if (!CryptGenRandom(crypt_prov, n, buffer)) {
> + error = GetLastError();
> + VLOG_ERR("CryptGenRandom: read error (%s)",
> ovs_retval_to_string(error));
> + }
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