[PATCH][next] smack: fix two memory leaks in smack_add_opt

[Al Viro]

On Sat, Dec 22, 2018 at 12:27:50PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> Currently if s is null or when returning via the error exit label
> out_opt_err leaks of the allocated opts can occur. Fix the leak
> on the null s case by checking s is null before the allocation. Fix
> the leak on the exit path by checking if opts was allocated by
> kfree'ing opts.
> 
> Detected by CoverityScan, CID#1475953 ("Resource leak")
> 
> Fixes: b2130173efae ("smack: take the guts of smack_parse_opts_str() into a new helper")
> Signed-off-by: Colin Ian King <colin.king at canonical.com>

There's a better fix in local tree, will go into -next tonight.