From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [Intel-gfx] [PATCH] i915/intel_tv_get_modes: fix strncpy truncation warning Date: Thu, 12 Jul 2018 15:44:01 +0300 Message-ID: <20180712124401.GZ5565@intel.com> References: <1531295175-24052-1-git-send-email-asmadeus@codewreck.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <1531295175-24052-1-git-send-email-asmadeus@codewreck.org> Sender: linux-kernel-owner@vger.kernel.org To: Dominique Martinet Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Wed, Jul 11, 2018 at 09:46:15AM +0200, Dominique Martinet wrote: > This is effectively no-op as the next line writes a nul at the final What is "This". Please write self contained commit messages. > byte of the buffer, so copying one letter less does not change the > behaviour. > > Signed-off-by: Dominique Martinet > --- > > gcc 8 gives the following warning, which I am not sure why is treated > as error for this file, thus making me fix it: > drivers/gpu/drm/i915/intel_tv.c: In function ‘intel_tv_get_modes’: > drivers/gpu/drm/i915/intel_tv.c:1358:3: error: ‘strncpy’ specified bound 32 equals destination size [-Werror=stringop-truncation] > strncpy(mode_ptr->name, input->name, DRM_DISPLAY_MODE_LEN); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors That warning should be in the actual commit message. > > > Also, as a side note, while checking if this was already sent I stumbled > uppon this: https://lists.freedesktop.org/archives/intel-gfx/2018-July/170638.html > ([Intel-gfx] [PATCH i-g-t 6/7] Fix truncate string in the strncpy) > which replaces strncpy(dest, src, sizeof(dest)) by strncpy(dest, src, > strlen(dest))... This isn't for linux but this looks like a pretty bad > idea to me... (I'm not on the list to reply there, sorry) > > drivers/gpu/drm/i915/intel_tv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c > index b55b5c157e38..f5614d07b10d 100644 > --- a/drivers/gpu/drm/i915/intel_tv.c > +++ b/drivers/gpu/drm/i915/intel_tv.c > @@ -1355,7 +1355,7 @@ intel_tv_get_modes(struct drm_connector *connector) > mode_ptr = drm_mode_create(connector->dev); > if (!mode_ptr) > continue; > - strncpy(mode_ptr->name, input->name, DRM_DISPLAY_MODE_LEN); > + strncpy(mode_ptr->name, input->name, DRM_DISPLAY_MODE_LEN - 1); > mode_ptr->name[DRM_DISPLAY_MODE_LEN - 1] = '\0'; This same pattern is used all over drm. Can you go and fix them all up? One might even consider writing a cocci patch for it ;) > > mode_ptr->hdisplay = hactive_s; > -- > 2.17.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel