include/crypto/random.h | 9 +++++++++ 5 files changed, 57 insertions(+), 8 deletions(-)
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 openeing neither file worked 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 initalizes 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>
---
crypto/init.c | 6 ++++++
crypto/random-gcrypt.c | 2 ++
crypto/random-gnutls.c | 3 +++
crypto/random-platform.c | 45
+++++++++++++++++++++++++++++++++++++--------
include/crypto/random.h | 9 +++++++++
5 files changed, 57 insertions(+), 8 deletions(-)
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 @@ int qcrypto_init(Error **errp)
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..2446142 100644
--- a/crypto/random-gcrypt.c
+++ b/crypto/random-gcrypt.c
@@ -31,3 +31,5 @@ int qcrypto_random_bytes(uint8_t *buf,
gcry_randomize(buf, buflen, GCRY_STRONG_RANDOM);
return 0;
}
+
+int qcrpto_random_init(Error **errp G_GNUC_UNUSED) { return 0; }
diff --git a/crypto/random-gnutls.c b/crypto/random-gnutls.c
index 04b45a8..d80c786 100644
--- a/crypto/random-gnutls.c
+++ b/crypto/random-gnutls.c
@@ -41,3 +41,6 @@ int qcrypto_random_bytes(uint8_t *buf,
return 0;
}
+
+
+int qcrpto_random_init(Error **errp G_GNUC_UNUSED) { return 0; }
diff --git a/crypto/random-platform.c b/crypto/random-platform.c
index 82b755a..c613b23 100644
--- a/crypto/random-platform.c
+++ b/crypto/random-platform.c
@@ -22,14 +22,23 @@
#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)
+{
+#ifdef _WIN32
+ if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
+ CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) {
+ error_setg_win32(errp, GetLastError(),
+ "Unable to create cryptographic provider");
+ return -1;
+ }
+#else
/* TBD perhaps also add support for BSD getentropy / Linux
* getrandom syscalls directly */
fd = open("/dev/urandom", O_RDONLY);
@@ -41,6 +50,18 @@ int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
error_setg(errp, "No /dev/urandom or /dev/random found");
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 @@ int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
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..82a3209 100644
--- a/include/crypto/random.h
+++ b/include/crypto/random.h
@@ -40,5 +40,14 @@ int qcrypto_random_bytes(uint8_t *buf,
size_t buflen,
Error **errp);
+/**
+ * qcrypto_random_init:
+ * @errp: pointer to a NULL-initialized error object
+ *
+ * Initalizes the handles used by qcrypto_random_bytes
+ *
+ * Returns 0 on success, -1 on error
+ */
+int qcrypto_random_init(Error **errp);
#endif /* QCRYPTO_RANDOM_H */
--
2.10.1.windows.1
On Tue, Apr 25, 2017 at 07:28:07PM +0200, Geert Martin Ijewski wrote: > 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 openeing neither file worked 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 initalizes 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> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> I'll add this to my queue unless someone raises further comments. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On 04/25/2017 12:28 PM, Geert Martin Ijewski wrote:
> 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 openeing neither file worked it
s/openeing/opening/
s/opening neither file worked/opening both files failed/
> 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 initalizes the (platform specific) handles that
s/initalizes/initializes/
> 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>
> ---
> +int qcrypto_random_init(Error **errp)
> +{
> +#ifdef _WIN32
Weird that you use #ifdef _WIN32 here...
> +int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
> + size_t buflen G_GNUC_UNUSED,
> + Error **errp)
> +{
> +#ifndef _WIN32
...but #ifndef here. It would be more consistent if all dual-implemented
functions have the #ifdefs in the same order, so that I can focus on
first or second half without having to check sense.
> +++ b/include/crypto/random.h
> @@ -40,5 +40,14 @@ int qcrypto_random_bytes(uint8_t *buf,
> size_t buflen,
> Error **errp);
>
> +/**
> + * qcrypto_random_init:
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Initalizes the handles used by qcrypto_random_bytes
s/Initalizes/Initializes/
> + *
> + * Returns 0 on success, -1 on error
> + */
> +int qcrypto_random_init(Error **errp);
>
> #endif /* QCRYPTO_RANDOM_H */
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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