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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 7 Jun 2022 14:26:40 -0700
Message-ID: <CAKwvOdkpA-P5763rt39q4HRjOdqC2Ca_Wu4suHU-qxpz3FkO8Q@mail.gmail.com>
Subject: Re: [PATCH 5/5] selinux: drop unnecessary NULL check
To:     Paul Moore <paul@paul-moore.com>
Cc:     =?UTF-8?Q?Christian_G=C3=B6ttsche?= <cgzones@googlemail.com>,
        selinux@vger.kernel.org,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        Eric Paris <eparis@parisplace.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Ondrej Mosnacek <omosnace@redhat.com>,
        Serge Hallyn <serge@hallyn.com>,
        Austin Kim <austin.kim@lge.com>,
        Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Yang Li <yang.lee@linux.alibaba.com>,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev
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On Tue, Jun 7, 2022 at 2:22 PM Paul Moore <paul@paul-moore.com> wrote:
>
> On Thu, Feb 17, 2022 at 9:22 AM Christian G=C3=B6ttsche
> <cgzones@googlemail.com> wrote:
> >
> > Commit e3489f8974e1 ("selinux: kill selinux_sb_get_mnt_opts()")
> > introduced a NULL check on the context after a successful call to
> > security_sid_to_context().  This is on the one hand redundant after
> > checking for success and on the other hand insufficient on an actual
> > NULL pointer, since the context is passed to seq_escape() leading to a
> > call of strlen() on it.
> >
> > Reported by Clang analyzer:
> >
> >     In file included from security/selinux/hooks.c:28:
> >     In file included from ./include/linux/tracehook.h:50:
> >     In file included from ./include/linux/memcontrol.h:13:
> >     In file included from ./include/linux/cgroup.h:18:
> >     ./include/linux/seq_file.h:136:25: warning: Null pointer passed as =
1st argument to string length function [unix.cstring.NullArg]
> >             seq_escape_mem(m, src, strlen(src), flags, esc);
> >                                    ^~~~~~~~~~~
> >
> > Signed-off-by: Christian G=C3=B6ttsche <cgzones@googlemail.com>
> > ---
> >  security/selinux/hooks.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> I was waiting for Nick to reply, but he never did, and this looks good
> to me so I just merged it into selinux/next.  Thanks for your patience
> Christian.

LGTM; you can ping me on irc #ndesaulniers on most kernel channels if
you're waiting on me. ;)

>
> --
> paul-moore.com


--=20
Thanks,
~Nick Desaulniers