[dpdk-dev] [PATCH v4 06/12] net/failsafe: add flexible device definition

[Gaëtan Rivet]

On Wed, May 31, 2017 at 08:19:36AM -0700, Stephen Hemminger wrote:
> On Mon, 29 May 2017 15:42:18 +0200
> Gaetan Rivet <gaetan.rivet at 6wind.com> wrote:
> 
> >  
> > +- **exec(<shell command>)** parameter
> > +
> > +  This parameter allows the user to provide a command to the fail-safe PMD to
> > +  execute and define a sub-device.
> > +  It is done within a regular shell context.
> > +  The first line of its output is read by the fail-safe PMD and otherwise
> > +  interpreted as if passed by the regular **dev** parameter.
> > +  Any other line is discarded.
> > +  If the command fail or output an incorrect string, the sub-device is not
> > +  initialized.
> > +  All commas within the ``shell command`` are replaced by spaces before
> > +  executing the command. This helps using scripts to specify devices.
> > +
> 
> Exec from a DPDK application seems like possible security hole since most DPDK applications
> have to run as root.
> 
> 

Users will run scripts or other programs that will launch fail-safe
instances. If a user launches a script over the fail-safe to configure
it or under it to detect devices, security seems at the same level?

> > static int
> > +fs_execute_cmd(struct sub_device *sdev, char *cmdline)
> > +{
> > +	FILE *fp;
> > +	/* store possible newline as well */
> > +	char output[DEVARGS_MAXLEN + 1];
> > +	size_t len;
> > +	int old_err;
> > +	int ret;
> > +
> > +	assert(cmdline != NULL || sdev->cmdline != NULL);
> > +	if (sdev->cmdline == NULL) {
> > +		char *new_str;
> > +		size_t i;
> > +
> > +		len = strlen(cmdline) + 1;
> > +		new_str = rte_realloc(sdev->cmdline, len,
> > +				RTE_CACHE_LINE_SIZE);
> > +		if (new_str == NULL) {
> > +			ERROR("Command line allocation failed");
> > +			return -ENOMEM;
> > +		}
> 
> Using rte_malloc for cmdline is way over optimizing. rte_malloc comes from huge page area
> which is limited. The only reason to use it is if the memory needs to be shared by primary/slave.
> Also rte_malloc has much less protection (memleak checkers, guards etc) compared to regular malloc.
> 

I agree, it should be changed.

-- 
Gaëtan Rivet
6WIND