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* [PATCH] i915/intel_tv_get_modes: fix strncpy truncation warning
@ 2018-07-11  7:46 Dominique Martinet
  2018-07-11 14:48   ` Chris Wilson
                   ` (4 more replies)
  0 siblings, 5 replies; 15+ messages in thread
From: Dominique Martinet @ 2018-07-11  7:46 UTC (permalink / raw)
  To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi
  Cc: David Airlie, intel-gfx, dri-devel, linux-kernel,
	Dominique Martinet

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 <asmadeus@codewreck.org>
---

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

^ permalink raw reply related	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2018-07-12 23:33 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-07-11  7:46 [PATCH] i915/intel_tv_get_modes: fix strncpy truncation warning Dominique Martinet
2018-07-11 14:48 ` Chris Wilson
2018-07-11 14:48   ` Chris Wilson
2018-07-11 14:58 ` ✓ Fi.CI.BAT: success for " Patchwork
2018-07-11 23:24 ` [PATCH v2] " Dominique Martinet
2018-07-12  7:39   ` Chris Wilson
2018-07-12  7:39     ` Chris Wilson
2018-07-12  9:19   ` Chris Wilson
2018-07-12  9:19     ` Chris Wilson
2018-07-12 12:44 ` [Intel-gfx] [PATCH] " Ville Syrjälä
2018-07-12 13:55   ` Dominique Martinet
2018-07-12 14:10     ` Ville Syrjälä
2018-07-12 14:10       ` [Intel-gfx] " Ville Syrjälä
2018-07-12 14:30       ` Dominique Martinet
2018-07-12 23:33 ` ✗ Fi.CI.BAT: failure for i915/intel_tv_get_modes: fix strncpy truncation warning (rev2) Patchwork

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