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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4620b1083e3sm20845830f8f.20.2026.06.18.07.59.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Jun 2026 07:59:41 -0700 (PDT) Date: Thu, 18 Jun 2026 15:59:39 +0100 From: David Laight To: Konrad Dybcio 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 Subject: Re: [PATCH next] drivers/rpmsg: Fix copy of channel->name into open request Message-ID: <20260618155939.6cdbdbac@pumpkin> In-Reply-To: <79c1dda2-153e-4b7a-ad18-c72db1cf4a00@oss.qualcomm.com> References: <20260608095523.2606-33-david.laight.linux@gmail.com> <79c1dda2-153e-4b7a-ad18-c72db1cf4a00@oss.qualcomm.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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. 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). David > > Konrad