RE: [PATCH] Tools: hv: verify origin of netlink connector message

[KY Srinivasan]

> -----Original Message-----
> From: Olaf Hering [mailto:olaf@xxxxxxxxx]
> Sent: Thursday, May 31, 2012 10:40 AM
> To: KY Srinivasan; Greg Kroah-Hartman
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] Tools: hv: verify origin of netlink connector message
> 
> The SuSE security team suggested to use recvfrom instead of recv to be
> certain that the connector message is originated from kernel.

Thanks Olaf.

> 
> Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

Signed-off-by:  K. Y. Srinivasan <kys@xxxxxxxxxxxxx>

> 
> ---
>  tools/hv/hv_kvp_daemon.c |   10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> Index: linux-3.4/tools/hv/hv_kvp_daemon.c
> ==============================================================
> =====
> --- linux-3.4.orig/tools/hv/hv_kvp_daemon.c
> +++ linux-3.4/tools/hv/hv_kvp_daemon.c
> @@ -701,14 +701,18 @@ int main(void)
>  	pfd.fd = fd;
> 
>  	while (1) {
> +		struct sockaddr *addr_p = (struct sockaddr *) &addr;
> +		socklen_t addr_l = sizeof(addr);
>  		pfd.events = POLLIN;
>  		pfd.revents = 0;
>  		poll(&pfd, 1, -1);
> 
> -		len = recv(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0);
> +		len = recvfrom(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0,
> +				addr_p, &addr_l);
> 
> -		if (len < 0) {
> -			syslog(LOG_ERR, "recv failed; error:%d", len);
> +		if (len < 0 || addr.nl_pid) {
> +			syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
> +					addr.nl_pid, errno, strerror(errno));
>  			close(fd);
>  			return -1;
>  		}
> 
> 

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