netdev - Re: [PATCH iproute2 2/2] lib/fs: Fix single return points for get_cgroup2

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Date:   Sat, 19 Dec 2020 00:29:05 +0100
From:   Andrea Claudi <aclaudi@...hat.com>
To:     Phil Sutter <phil@....cc>, Andrea Claudi <aclaudi@...hat.com>,
        linux-netdev <netdev@...r.kernel.org>,
        Stephen Hemminger <stephen@...workplumber.org>,
        David Ahern <dsahern@...il.com>
Subject: Re: [PATCH iproute2 2/2] lib/fs: Fix single return points for get_cgroup2_*

On Sat, Dec 19, 2020 at 12:08 AM Phil Sutter <phil@....cc> wrote:
>
> On Fri, Dec 18, 2020 at 08:09:23PM +0100, Andrea Claudi wrote:
> > Functions get_cgroup2_id() and get_cgroup2_path() uncorrectly performs
> > cleanup on the single return point. Both of them may get to use close()
> > with a negative argument, if open() fails.
> >
> > Fix this adding proper labels and gotos to make sure we clean up only
> > resources we are effectively used before.
>
> Since free(NULL) is OK according to POSIX, the fds are initialized to -1
> and open() returns -1 on error, you may simplify these
> changes down to making the close() calls conditional:
>
> | if (fd >= 0)
> |       close(fd);
>
> Cheers, Phil
>

Thanks for the suggestion, Phil. Will do in v2.