crypto: qcrypto_random_bytes() now works on windows w/o any other crypto libs
If no crypto library is included in the build, QEMU uses
qcrypto_random_bytes() to generate random data. That function tried to open
/dev/urandom or /dev/random and if opening both files failed it errored out.
Those files obviously do not exist on windows, so there the code uses
CryptGenRandom().
Furthermore there was some refactoring and a new function
qcrypto_random_init() was introduced. If a proper crypto library (gnutls or
libgcrypt) is included in the build, this function does nothing. If neither
is included it initializes the (platform specific) handles that are used by
qcrypto_random_bytes().
Either:
* a handle to /dev/urandom | /dev/random on unix like systems
* a handle to a cryptographic service provider on windows
Signed-off-by: Geert Martin Ijewski <gm.ijewski@web.de>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
diff --git a/crypto/init.c b/crypto/init.c
index f65207e..f131c42 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -32,6 +32,8 @@
#include <gcrypt.h>
#endif
+#include "crypto/random.h"
+
/* #define DEBUG_GNUTLS */
/*
@@ -146,5 +148,9 @@
gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
#endif
+ if (qcrypto_random_init(errp) < 0) {
+ return -1;
+ }
+
return 0;
}
diff --git a/crypto/random-gcrypt.c b/crypto/random-gcrypt.c
index 0de9a09..9f1c9ee 100644
--- a/crypto/random-gcrypt.c
+++ b/crypto/random-gcrypt.c
@@ -31,3 +31,5 @@
gcry_randomize(buf, buflen, GCRY_STRONG_RANDOM);
return 0;
}
+
+int qcrypto_random_init(Error **errp G_GNUC_UNUSED) { return 0; }
diff --git a/crypto/random-gnutls.c b/crypto/random-gnutls.c
index 04b45a8..5350003 100644
--- a/crypto/random-gnutls.c
+++ b/crypto/random-gnutls.c
@@ -41,3 +41,6 @@
return 0;
}
+
+
+int qcrypto_random_init(Error **errp G_GNUC_UNUSED) { return 0; }
diff --git a/crypto/random-platform.c b/crypto/random-platform.c
index 82b755a..0eddb91 100644
--- a/crypto/random-platform.c
+++ b/crypto/random-platform.c
@@ -22,14 +22,16 @@
#include "crypto/random.h"
-int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
- size_t buflen G_GNUC_UNUSED,
- Error **errp)
-{
- int fd;
- int ret = -1;
- int got;
+#ifdef _WIN32
+#include <Wincrypt.h>
+static HCRYPTPROV hCryptProv;
+#else
+static int fd; /* a file handle to either /dev/urandom or /dev/random */
+#endif
+int qcrypto_random_init(Error **errp)
+{
+#ifndef _WIN32
/* TBD perhaps also add support for BSD getentropy / Linux
* getrandom syscalls directly */
fd = open("/dev/urandom", O_RDONLY);
@@ -41,6 +43,25 @@
error_setg(errp, "No /dev/urandom or /dev/random found");
return -1;
}
+#else
+ if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
+ CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) {
+ error_setg_win32(errp, GetLastError(),
+ "Unable to create cryptographic provider");
+ return -1;
+ }
+#endif
+
+ return 0;
+}
+
+int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
+ size_t buflen G_GNUC_UNUSED,
+ Error **errp)
+{
+#ifndef _WIN32
+ int ret = -1;
+ int got;
while (buflen > 0) {
got = read(fd, buf, buflen);
@@ -59,6 +80,14 @@
ret = 0;
cleanup:
- close(fd);
return ret;
+#else
+ if (!CryptGenRandom(hCryptProv, buflen, buf)) {
+ error_setg_win32(errp, GetLastError(),
+ "Unable to read random bytes");
+ return -1;
+ }
+
+ return 0;
+#endif
}
diff --git a/include/crypto/random.h b/include/crypto/random.h
index a101353..a07229c 100644
--- a/include/crypto/random.h
+++ b/include/crypto/random.h
@@ -40,5 +40,14 @@
size_t buflen,
Error **errp);
+/**
+ * qcrypto_random_init:
+ * @errp: pointer to a NULL-initialized error object
+ *
+ * Initializes the handles used by qcrypto_random_bytes
+ *
+ * Returns 0 on success, -1 on error
+ */
+int qcrypto_random_init(Error **errp);
#endif /* QCRYPTO_RANDOM_H */
