Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20211009063053.187953-1-cuigaosheng1@huawei.com>
In-Reply-To: <20211009063053.187953-1-cuigaosheng1@huawei.com>
From:   Paul Moore <paul@paul-moore.com>
Date:   Tue, 12 Oct 2021 10:15:34 -0400
Message-ID: <CAHC9VhRopU95Vxroaa4JxWkt=gK7KgJjvK+t9kmkQZTor63p_g@mail.gmail.com>
Subject: Re: [PATCH -next] integrity: return early if audit_log_start return NULL
To:     Gaosheng Cui <cuigaosheng1@huawei.com>
Cc:     James Morris <jmorris@namei.org>, Serge Hallyn <serge@hallyn.com>,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, xiujianfeng@huawei.com,
        wangweiyang2@huawei.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Sat, Oct 9, 2021 at 2:28 AM Gaosheng Cui <cuigaosheng1@huawei.com> wrote:
>
> audit_log_start() may return NULL in below cases:
>   - when audit is not initialized.
>   - when audit backlog limit exceeds.
>
> After the call to audit_log_start() is made and then possible NULL audit
> buffer argument is passed to audit_log_*() functions, audit_log_*()
> functions return immediately in case of a NULL audit buffer argument.
>
> It is not necessary for audit_log_*() functions to be called with
> NULL audit buffer argument, so return early when audit_log_start()
> returns NULL.
>
> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> ---
>  security/integrity/integrity_audit.c | 2 ++
>  1 file changed, 2 insertions(+)

Acked-by: Paul Moore <paul@paul-moore.com>

> diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
> index 29220056207f..fbc032185d72 100644
> --- a/security/integrity/integrity_audit.c
> +++ b/security/integrity/integrity_audit.c
> @@ -45,6 +45,8 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
>                 return;
>
>         ab = audit_log_start(audit_context(), GFP_KERNEL, audit_msgno);
> +       if (unlikely(!ab))
> +               return;
>         audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u",
>                          task_pid_nr(current),
>                          from_kuid(&init_user_ns, current_uid()),
> --
> 2.30.0

-- 
paul moore
www.paul-moore.com