From: Nick Desaulniers <ndesaulniers@google.com>
To: Tom Rix <trix@redhat.com>
Cc: john.johansen@canonical.com, James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Nathan Chancellor <natechancellor@gmail.com>,
linux-security-module@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] apparmor: fix error check
Date: Mon, 21 Dec 2020 11:22:11 -0800 [thread overview]
Message-ID: <CAKwvOdnjEDnReJ8+dK=S+FaQW29gR8q+9d5XSuUXrTrvWoiM5w@mail.gmail.com> (raw)
In-Reply-To: <20201004142422.5717-1-trix@redhat.com>
On Sun, Oct 4, 2020 at 7:24 AM <trix@redhat.com> wrote:
>
> From: Tom Rix <trix@redhat.com>
>
> clang static analysis reports this representative problem:
>
> label.c:1463:16: warning: Assigned value is garbage or undefined
> label->hname = name;
> ^ ~~~~
Right, so if aa_label_acntsxprint() fails, it won't assign to its
first param. In the caller, this means assigning uninitialized memory
(UB) when aa_label_acntsxprint() returns -ENOMEM for example. Thanks
for the patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
>
> In aa_update_label_name(), this the problem block of code
>
> if (aa_label_acntsxprint(&name, ...) == -1)
> return res;
>
> On failure, aa_label_acntsxprint() has a more complicated return
> that just -1. So check for a negative return.
>
> It was also noted that the aa_label_acntsxprint() main comment refers
> to a nonexistent parameter, so clean up the comment.
>
> Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels")
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
> security/apparmor/label.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/security/apparmor/label.c b/security/apparmor/label.c
> index e68bcedca976..6222fdfebe4e 100644
> --- a/security/apparmor/label.c
> +++ b/security/apparmor/label.c
> @@ -1454,7 +1454,7 @@ bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp)
> if (label->hname || labels_ns(label) != ns)
> return res;
>
> - if (aa_label_acntsxprint(&name, ns, label, FLAGS_NONE, gfp) == -1)
> + if (aa_label_acntsxprint(&name, ns, label, FLAGS_NONE, gfp) < 0)
> return res;
>
> ls = labels_set(label);
> @@ -1704,7 +1704,7 @@ int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
>
> /**
> * aa_label_acntsxprint - allocate a __counted string buffer and print label
> - * @strp: buffer to write to. (MAY BE NULL if @size == 0)
> + * @strp: buffer to write to.
> * @ns: namespace profile is being viewed from
> * @label: label to view (NOT NULL)
> * @flags: flags controlling what label info is printed
> --
> 2.18.1
>
> --
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--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2020-12-21 19:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-04 14:24 [PATCH] apparmor: fix error check trix
2020-12-21 19:22 ` Nick Desaulniers [this message]
2021-02-07 11:27 ` John Johansen
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