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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Fri, 4 Aug 2023 08:49:48 -0700
Message-ID: <CAKwvOd=1pEE=pspfg7fcofYF5=eziFvcLJgC0_ohG7jq+rbVyg@mail.gmail.com>
Subject: Re: [PATCH v2] fs: lockd: avoid possible wrong NULL parameter
To:     Su Hui <suhui@nfschina.com>
Cc:     trond.myklebust@hammerspace.com, anna@kernel.org,
        chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de,
        kolga@netapp.com, Dai.Ngo@oracle.com, tom@talpey.com,
        nathan@kernel.org, trix@redhat.com, bfields@fieldses.org,
        linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, kernel-janitors@vger.kernel.org
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On Thu, Aug 3, 2023 at 6:28=E2=80=AFPM Su Hui <suhui@nfschina.com> wrote:
>
> clang's static analysis warning: fs/lockd/mon.c: line 293, column 2:
> Null pointer passed as 2nd argument to memory copy function.
>
> Assuming 'hostname' is NULL and calling 'nsm_create_handle()', this will
> pass NULL as 2nd argument to memory copy function 'memcpy()'. So return
> NULL if 'hostname' is invalid.
>
> Fixes: 77a3ef33e2de ("NSM: More clean up of nsm_get_handle()")
> Signed-off-by: Su Hui <suhui@nfschina.com>

Thanks for the patch! And thanks for checking clang static analysis reports=
!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
> v2:
>  - move NULL check to the callee "nsm_create_handle()"
>  fs/lockd/mon.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
> index 1d9488cf0534..87a0f207df0b 100644
> --- a/fs/lockd/mon.c
> +++ b/fs/lockd/mon.c
> @@ -276,6 +276,9 @@ static struct nsm_handle *nsm_create_handle(const str=
uct sockaddr *sap,
>  {
>         struct nsm_handle *new;
>
> +       if (!hostname)
> +               return NULL;
> +
>         new =3D kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
>         if (unlikely(new =3D=3D NULL))
>                 return NULL;
> --
> 2.30.2
>


--=20
Thanks,
~Nick Desaulniers