[LTP] [PATCH v2] sctp_big_chunk: Do not use md5 hmac algo if fips is enabled

[Petr Vorel]

Hi,

> MD5 is not FIPS compliant. But still md5 is used as the default algorithm for sctp
> even when fips is enabled. Due to this, sctp_big_chunk testcase is failing because listen()
> system call in setup_server() is failing in fips environment.

> Fix is to not use md5 algorithm while setting up server, instead set it to none

> Signed-Off by: Ashwin Dayanand Kamat <kashwindayan@vmware.com>
> ----
> v2:
> As per the review comments given by Petr, did below changes in v2,
>         * Moved the logic to sctp_server() function
>         * Setting none as the default algo
>         * make sure cookie_hmac_alg file is present before accessing it
BTW I suggested modprobe, because I'm not aware of other way to trigger it.
But maybe creating SCTP socket would trigger it, e.g.
socket(PF_INET, SOCK_STREAM, IPPROTO_SCTP);

If yes, IMHO it'd be more elegant solution and (likely) we would not depend on
modprobe.

Kind regards,
Petr

> ---
>  testcases/network/sctp/sctp_big_chunk.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)

> diff --git a/testcases/network/sctp/sctp_big_chunk.c b/testcases/network/sctp/sctp_big_chunk.c
> index a6a326ea2..31786dd39 100644
> --- a/testcases/network/sctp/sctp_big_chunk.c
> +++ b/testcases/network/sctp/sctp_big_chunk.c
> @@ -34,6 +34,24 @@ static int addr_num = 3273;

>  static void setup_server(void)
>  {
> +	const char *const cmd_modprobe[] = {"modprobe", "sctp", NULL};
> +	const char hmac_algo_path[] = "/proc/sys/net/sctp/cookie_hmac_alg";
> +	char hmac_algo[CHAR_MAX];
> +	int hmac_algo_changed = 0;
> +
> +	/* Disable md5 if fips is enabled. Set it to none */
> +	if (tst_fips_enabled()) {
> +		if (access(hmac_algo_path, F_OK) < 0) {
> +			SAFE_CMD(cmd_modprobe, NULL, NULL);
> +		}
> +
> +		if (!access(hmac_algo_path, F_OK)) {
> +			SAFE_FILE_SCANF(hmac_algo_path, "%s", hmac_algo);
> +			SAFE_FILE_PRINTF(hmac_algo_path, "%s", "none");
> +			hmac_algo_changed = 1;
> +		}
> +	}
> +
>  	loc.sin6_family = AF_INET6;
>  	loc.sin6_addr = in6addr_loopback;

> @@ -46,6 +64,9 @@ static void setup_server(void)
>  	SAFE_LISTEN(sfd, 1);

>  	srand(port);
> +
> +	if (hmac_algo_changed)
> +		SAFE_FILE_PRINTF(hmac_algo_path, "%s", hmac_algo);
>  }

>  static void update_packet_field(size_t *off, void *buf, size_t buf_len)