Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain;
        charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.20\))
Subject: Re: [PATCH 06/12] append_pathname: check the value returned by
 realloc to avoid segfault
From:   =?utf-8?B?0JHQu9Cw0LPQvtC00LDRgNC10L3QutC+INCQ0YDRgtGR0Lw=?= 
        <artem.blagodarenko@gmail.com>
In-Reply-To: <07fe127f-3814-7d12-dea6-b84d9ab4410e@huawei.com>
Date:   Tue, 25 May 2021 12:37:13 +0300
Cc:     linux-ext4@vger.kernel.org, liuzhiqiang26@huawei.com,
        linfeilong@huawei.com
Content-Transfer-Encoding: quoted-printable
Message-Id: <1979B168-38E8-4D35-B8D7-2D47D04ED344@gmail.com>
References: <266bc52e-e279-ce84-0e1f-1405b9bc6174@huawei.com>
 <07fe127f-3814-7d12-dea6-b84d9ab4410e@huawei.com>
To:     Wu Guanghao <wuguanghao3@huawei.com>
Precedence: bulk

Hello Wu,

Thanks for the patch.

> On 24 May 2021, at 14:23, Wu Guanghao <wuguanghao3@huawei.com> wrote:
>=20
> In append_pathname(), we need to add a new path to save the value =
returned by realloc,
> otherwise the name->path may be NULL, causing segfault
>=20
> Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
> ---
> contrib/fsstress.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>=20
> diff --git a/contrib/fsstress.c b/contrib/fsstress.c
> index 2a983482..530bd920 100644
> --- a/contrib/fsstress.c
> +++ b/contrib/fsstress.c
> @@ -599,7 +599,7 @@ void add_to_flist(int ft, int id, int parent)
> void append_pathname(pathname_t * name, char *str)
> {
> 	int len;
> -
> +	char *path;:
> 	len =3D strlen(str);
> #ifdef DEBUG
> 	if (len && *str =3D=3D '/' && name->len =3D=3D 0) {
> @@ -609,7 +609,13 @@ void append_pathname(pathname_t * name, char =
*str)
>=20
> 	}
> #endif
> -	name->path =3D realloc(name->path, name->len + 1 + len);
> +	path =3D realloc(name->path, name->len + 1 + len);
> +	if (path =3D=3D NULL) {
> +		fprintf(stderr, "fsstress: append_pathname realloc =
failed\n");
> +		chadir(homedir);

Did you mean chdir() here?

> +		abort();
> +	}
> +	name->path =3D path;
> 	strcpy(&name->path[name->len], str);
> 	name->len +=3D len;
> }
> --=20


Thanks,
Best regards,
Artem Blagodarenko.