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Mon, 22 Jun 2026 06:37:12 -0700 (PDT) X-Received: by 2002:a05:6102:3e2a:b0:633:3bf6:977c with SMTP id ada2fe7eead31-72b1402325fmr2041691137.1.1782135432502; Mon, 22 Jun 2026 06:37:12 -0700 (PDT) Received: from [192.168.120.170] ([178.235.128.140]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c0c610e12f6sm376327566b.47.2026.06.22.06.37.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Jun 2026 06:37:11 -0700 (PDT) Message-ID: Date: Mon, 22 Jun 2026 15:37:09 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH next] drivers/rpmsg: Fix copy of channel->name into open request To: David Laight Cc: Kees Cook , linux-hardening@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org, Arnd Bergmann , Bjorn Andersson , Mathieu Poirier References: <20260608095523.2606-33-david.laight.linux@gmail.com> <79c1dda2-153e-4b7a-ad18-c72db1cf4a00@oss.qualcomm.com> <20260618155939.6cdbdbac@pumpkin> Content-Language: en-US From: Konrad Dybcio In-Reply-To: <20260618155939.6cdbdbac@pumpkin> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-GUID: PySGnK3dhBYhp0ZcP65Pf8SmQ7qSy6ul X-Proofpoint-ORIG-GUID: PySGnK3dhBYhp0ZcP65Pf8SmQ7qSy6ul X-Authority-Analysis: v=2.4 cv=PuKjqQM3 c=1 sm=1 tr=0 ts=6a393a89 cx=c_pps a=+D9SDfe9YZWTjADjLiQY5g==:117 a=PRfkaYvzSr8QmIIGAkY2Sg==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=yOCtJkima9RkubShWh1s:22 a=EUspDBNiAAAA:8 a=pGLkceISAAAA:8 a=UhM6YWHzZrMyvu7RIJkA:9 a=QEXdDO2ut3YA:10 a=vmgOmaN-Xu0dpDh8OwbV:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjIyMDEzNCBTYWx0ZWRfXzkkNH9NdvgU4 cUVePxMWt+8HOFPz2jIpX2ioKor0cVaRzOS6C1SBe16MYBIeNLaEIuBBQ0n92HUM/NoZLreeDvH UOmU2rSOC5uYgsQcssy7KIkrgDo4MRI= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjIyMDEzNCBTYWx0ZWRfX3QjPszWOvjjN KXwpamLChUr8zL0eRWkYsE2CPL4YVr+SV06dNDMY6jdRix2HB1LBhoQGkCMeApB26pUIGbaISyf EY5PJU/uIjktf2dR8ttoSqTqe/futYRoXtV7EWDulaR1jhJ0ONdDTYOM4snAAtL8zPunjQhTotR 0m+TTW4EKW4aBq1He70juNSREJnUVVKfP/eEfqfW7J2Nw8FUrWNYQjR0w9ZPpDMZfEnGS9Q2eom TP7RujCCVE7/82K3NIsYn7GsKMyeothRL+/1Lum89NkTQJRfKmgFIfeFub3g1iDtsxOBXqVUfcv RQqQqrYsqtts1UjM7I3NsY59J8jGXowFwlSl0WlxdqMpOGZBOeMlm5aTiUAtGXOsrv5r6kDJzXE gnAMikiyrdH6I0Z7jdX7A5hfasfAgOX6zzZFqJ6TVKCrjn0aaslhMMECXK6zZapAjfb71l2cL2W NzzY8D7w7gzNye3x72w== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-22_02,2026-06-22_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 priorityscore=1501 phishscore=0 impostorscore=0 adultscore=0 clxscore=1015 bulkscore=0 spamscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606220134 On 6/18/26 4:59 PM, David Laight wrote: > On Thu, 18 Jun 2026 15:24:17 +0200 > Konrad Dybcio wrote: > >> On 6/8/26 11:55 AM, david.laight.linux@gmail.com wrote: >>> From: David Laight >>> >>> Nothing obvious ensures that the name is less than GLINK_CMD_OPEN (32) >> ^ GLINK_NAME_SIZE > > I was writing a lot of commit messages, most with -m 'text'. > >> [...] >> >>> @@ -481,8 +481,7 @@ static int qcom_glink_send_open_req(struct qcom_glink *glink, >>> struct glink_channel *channel) >>> { >>> DEFINE_RAW_FLEX(struct glink_msg, req, data, GLINK_NAME_SIZE); >>> - int name_len = strlen(channel->name) + 1; >>> - int req_len = ALIGN(sizeof(*req) + name_len, 8); >>> + int name_len, req_len; >>> int ret; >>> unsigned long flags; >>> >>> @@ -498,14 +497,20 @@ static int qcom_glink_send_open_req(struct qcom_glink *glink, >>> >>> channel->lcid = ret; >>> >>> + name_len = strscpy_pad(req->data, channel->name, GLINK_NAME_SIZE); >>> + if (name_len < 0) >>> + name_len = GLINK_NAME_SIZE; >>> + else >>> + name_len++; >> >> Should we perhaps do something along the lines of: >> >> WARN_ON(strlen(name) > GLINK_NAME_SIZE) >> >> to prevent silent clipping? > > strscpy() tells you whether the copy got truncated. > No point calling strlen() again. Right. > But I'm not really sure it is worth it. > Any length check of user-supplied names should be much earlier, > this is just ensuring this code doesn't overwrite its own stack. > (and ensuring stale stack doesn't get sent as padding). Fair. I'll check that out separately. Reviewed-by: Konrad Dybcio Konrad