Re: [Qemu-devel] [PATCH v3] crypto: qcrypto_random_bytes() now works on windows w/o any other crypto lib

[Eric Blake <eblake@redhat.com>]

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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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