linux-kernel - Re: [PATCH] scsi: ibmvscsis: Fix a stringop-overflow warning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGXu5j+-RNeEr+FUc6maamvzYpY7W0VJ-yYGDHnFTuNPeOUMFw@mail.gmail.com>
Date:   Mon, 10 Sep 2018 16:30:46 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Laura Abbott <labbott@...hat.com>
Cc:     "Bryant G. Ly" <bryantly@...ux.vnet.ibm.com>,
        Michael Cyr <mikecyr@...ux.vnet.ibm.com>,
        "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org,
        target-devel <target-devel@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Prarit Bhargava <prarit@...hat.com>
Subject: Re: [PATCH] scsi: ibmvscsis: Fix a stringop-overflow warning

On Mon, Sep 10, 2018 at 3:37 PM, Laura Abbott <labbott@...hat.com> wrote:
> There's currently a warning about string overflow with strncat:
>
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_probe':
> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:3479:2: error: 'strncat' specified
> bound 64 equals destination size [-Werror=stringop-overflow=]
>   strncat(vscsi->eye, vdev->name, MAX_EYE);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Switch to using strlcat which correctly accounts for lengths that
> are equal to the destination buffer.
>
> Signed-off-by: Laura Abbott <labbott@...hat.com>
> ---
>  drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> index fac377320158..53d344d8dc43 100644
> --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
> @@ -3475,7 +3475,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
>                 vscsi->dds.window[REMOTE].liobn);
>
>         strcpy(vscsi->eye, "VSCSI ");
> -       strncat(vscsi->eye, vdev->name, MAX_EYE);
> +       strlcat(vscsi->eye, vdev->name, MAX_EYE);

Can this just get switched to snprintf() instead?

snprintf(vscsi->eye, sizeof(vscsi->eye), "VSCSI%s", vdev->name);

>         vscsi->dds.unit_id = vdev->unit_address;
>         strncpy(vscsi->dds.partition_name, partition_name,

And does this strncpy need a NUL-termination and/or trailing padding?

-Kees

-- 
Kees Cook
Pixel Security