From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominique Martinet Subject: =?UTF-8?q?=5BPATCH=5D=20i915/intel=5Ftv=5Fget=5Fmodes=3A=20fix=20strncpy=20truncation=20warning?= Date: Wed, 11 Jul 2018 09:46:15 +0200 Message-ID: <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: Sender: linux-kernel-owner@vger.kernel.org To: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi Cc: David Airlie , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dominique Martinet List-Id: dri-devel@lists.freedesktop.org This is effectively no-op as the next line writes a nul at the final 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 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'; mode_ptr->hdisplay = hactive_s; -- 2.17.1