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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4548ec6cd75sm19908276f8f.16.2026.05.10.15.08.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 10 May 2026 15:08:55 -0700 (PDT) Date: Sun, 10 May 2026 23:08:53 +0100 From: David Laight To: "Alexander A. Klimov" Cc: Shubhrajyoti Datta , Borislav Petkov , Tony Luck , Kees Cook , Arnd Bergmann , Greg Kroah-Hartman , Nick Li , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , linux-edac@vger.kernel.org, Linux Kernel Mailing List , linux-sound@vger.kernel.org Subject: Re: [PATCH] Fix possible strscpy() buffer overflows Message-ID: <20260510230853.154050a2@pumpkin> In-Reply-To: <7cb7d771-5bf1-4d26-ac0f-c8968372bfba@al2klimov.de> References: <7cb7d771-5bf1-4d26-ac0f-c8968372bfba@al2klimov.de> 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 Sun, 10 May 2026 20:24:41 +0200 "Alexander A. Klimov" wrote: > In the changed files, strings were copied like this: > > strscpy(DST, SRC, strlen(SRC)); > > A buffer overflow would happen if strlen(SRC) > sizeof(DST). > Actually, strscpy() must be used this way: > > strscpy(DST, SRC, sizeof(DST)); > strscpy(DST, SRC); // defaults to sizeof(DST) Nak. This is test code and deliberately doing things 'wrong'. -- David > > Signed-off-by: Alexander A. Klimov > --- > drivers/edac/versalnet_edac.c | 3 +-- > drivers/misc/lkdtm/fortify.c | 6 +----- > sound/soc/codecs/fs210x.c | 2 +- > 3 files changed, 3 insertions(+), 8 deletions(-) > > diff --git a/drivers/edac/versalnet_edac.c b/drivers/edac/versalnet_edac.c > index ec13155824..daa140f4db 100644 > --- a/drivers/edac/versalnet_edac.c > +++ b/drivers/edac/versalnet_edac.c > @@ -728,8 +728,7 @@ static int rpmsg_probe(struct rpmsg_device *rpdev) > pg = (struct mc_priv *)amd_rpmsg_id_table[0].driver_data; > chinfo.src = RPMSG_ADDR_ANY; > chinfo.dst = rpdev->dst; > - strscpy(chinfo.name, amd_rpmsg_id_table[0].name, > - strlen(amd_rpmsg_id_table[0].name)); > + strscpy(chinfo.name, amd_rpmsg_id_table[0].name); > > pg->ept = rpmsg_create_ept(rpdev, rpmsg_cb, NULL, chinfo); > if (!pg->ept) > diff --git a/drivers/misc/lkdtm/fortify.c b/drivers/misc/lkdtm/fortify.c > index 7615a02dfc..9a9159a120 100644 > --- a/drivers/misc/lkdtm/fortify.c > +++ b/drivers/misc/lkdtm/fortify.c > @@ -174,11 +174,7 @@ static void lkdtm_FORTIFY_STRSCPY(void) > /* Restore src to its initial value. */ > src[3] = 'b'; > > - /* > - * Use strlen here so size cannot be known at compile time and there is > - * a runtime write overflow. > - */ > - strscpy(dst, src, strlen(src)); > + strscpy(dst, src); > > pr_err("FAIL: strscpy() overflow not detected!\n"); > pr_expected_config(CONFIG_FORTIFY_SOURCE); > diff --git a/sound/soc/codecs/fs210x.c b/sound/soc/codecs/fs210x.c > index e6195b71ad..eda716f817 100644 > --- a/sound/soc/codecs/fs210x.c > +++ b/sound/soc/codecs/fs210x.c > @@ -968,7 +968,7 @@ static int fs210x_effect_scene_info(struct snd_kcontrol *kcontrol, > if (scene->name) > name = scene->name; > > - strscpy(uinfo->value.enumerated.name, name, strlen(name) + 1); > + strscpy(uinfo->value.enumerated.name, name); > > return 0; > }