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To: Piotr Azarewicz <piotrx.t.azarewicz@intel.com>, dev@dpdk.org
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From: Declan Doherty <declan.doherty@intel.com>
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Date: Wed, 13 Jul 2016 16:55:43 +0100
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Subject: Re: [dpdk-dev] [PATCH v1 1/1] examples/l2fwd-crypto: improve random
 key generator
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On 05/25/2016 02:34 PM, Piotr Azarewicz wrote:
> This patch improve generate_random_key() function by replacing rand()
> function with reading from /dev/urandom.
>
> CID 120136 : Calling risky function (DC.WEAK_CRYPTO)
> dont_call: rand should not be used for security related applications, as
> linear congruential algorithms are too easy to break
>
> Coverity issue: 120136
>
> Signed-off-by: Piotr Azarewicz <piotrx.t.azarewicz@intel.com>
> ---
>  examples/l2fwd-crypto/main.c |   18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/examples/l2fwd-crypto/main.c b/examples/l2fwd-crypto/main.c
> index d18c813..e1f0a1e 100644
> --- a/examples/l2fwd-crypto/main.c
> +++ b/examples/l2fwd-crypto/main.c
> @@ -45,6 +45,8 @@
>  #include <ctype.h>
>  #include <errno.h>
>  #include <getopt.h>
> +#include <fcntl.h>
> +#include <unistd.h>
>
>  #include <rte_atomic.h>
>  #include <rte_branch_prediction.h>
> @@ -581,10 +583,18 @@ l2fwd_simple_forward(struct rte_mbuf *m, unsigned portid)
>  static void
>  generate_random_key(uint8_t *key, unsigned length)
>  {
> -	unsigned i;
> +	int fd;
> +	int ret;
> +
> +	fd = open("/dev/urandom", O_RDONLY);
> +	if (fd < 0)
> +		rte_exit(EXIT_FAILURE, "Failed to generate random key\n");
>
> -	for (i = 0; i < length; i++)
> -		key[i] = rand() % 0xff;
> +	ret = read(fd, key, length);
> +	close(fd);
> +
> +	if (ret != (signed)length)
> +		rte_exit(EXIT_FAILURE, "Failed to generate random key\n");
>  }
>
>  static struct rte_cryptodev_sym_session *
> @@ -1180,8 +1190,6 @@ l2fwd_crypto_parse_timer_period(struct l2fwd_crypto_options *options,
>  static void
>  l2fwd_crypto_default_options(struct l2fwd_crypto_options *options)
>  {
> -	srand(time(NULL));
> -
>  	options->portmask = 0xffffffff;
>  	options->nb_ports_per_lcore = 1;
>  	options->refresh_period = 10000;
>

Acked-by: Declan Doherty <declan.doherty@intel.com>