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[209.85.219.177]) by smtp.gmail.com with ESMTPSA id j6-v6sm6830166ywe.107.2018.09.11.11.28.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Sep 2018 11:28:00 -0700 (PDT) Received: by mail-yb1-f177.google.com with SMTP id l16-v6so9704219ybk.11 for ; Tue, 11 Sep 2018 11:28:00 -0700 (PDT) X-Received: by 2002:a25:19c3:: with SMTP id 186-v6mr13195705ybz.410.1536690479668; Tue, 11 Sep 2018 11:27:59 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a25:5f04:0:0:0:0:0 with HTTP; Tue, 11 Sep 2018 11:27:58 -0700 (PDT) In-Reply-To: References: <20180911180542.7778-1-labbott@redhat.com> From: Kees Cook Date: Tue, 11 Sep 2018 11:27:58 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCHv2] scsi: ibmvscsis: Fix a stringop-overflow warning To: Laura Abbott Cc: "Bryant G. Ly" , Michael Cyr , "James E.J. Bottomley" , "Martin K. Petersen" , linux-scsi@vger.kernel.org, target-devel , LKML , Prarit Bhargava Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 11, 2018 at 11:24 AM, Kees Cook wrote: > On Tue, Sep 11, 2018 at 11:05 AM, Laura Abbott 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 a single snprintf instead of a strcpy + strcat to handle this >> cleanly. >> >> Signed-off-by: Laura Abbott > > Reviewed-by: Kees Cook > > -Kees > >> --- >> v2: Swtich to using snprintf per suggestion of Kees >> --- >> drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c >> index fac377320158..9305440a00a1 100644 >> --- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c >> +++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c >> @@ -3474,8 +3474,7 @@ static int ibmvscsis_probe(struct vio_dev *vdev, >> vscsi->dds.window[LOCAL].liobn, >> vscsi->dds.window[REMOTE].liobn); >> >> - strcpy(vscsi->eye, "VSCSI "); >> - strncat(vscsi->eye, vdev->name, MAX_EYE); >> + snprintf(vscsi->eye, sizeof(vscsi->eye), "VSCSI%s", vdev->name); Eek. No, I take it back: Nick Desaulniers has better eyes than me and pointed out that there should be a space after VSCSI. -Kees >> >> vscsi->dds.unit_id = vdev->unit_address; >> strncpy(vscsi->dds.partition_name, partition_name, >> -- >> 2.17.1 >> > > > > -- > Kees Cook > Pixel Security -- Kees Cook Pixel Security