From 090afc1e40f411144e112431da279bafe7e734ff Mon Sep 17 00:00:00 2001 From: Nicholas Kazlauskas Date: Fri, 20 Jul 2018 10:17:29 -0400 Subject: [PATCH] drm/amd/display: Fix overflow/truncation from strncpy. [Why] New GCC warnings for stringop-truncation and stringop-overflow help catch common misuse of strncpy. This patch suppresses these warnings by fixing bugs identified by them. [How] Since the parameter passed for name in amdpgu_dm_create_common_mode has no fixed length, if the string is >= DRM_DISPLAY_MODE_LEN then mode->name will not be null-terminated. The truncation in fill_audio_info won't actually occur (and the string will be null-terminated since the buffer is initialized to zero), but the warning can be suppressed by using the proper buffer size. This patch fixes both issues by using the real size for the buffer and making use of strscpy (which always terminates). Signed-off-by: Nicholas Kazlauskas Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 33b605b259c2..5a6edf65c9ea 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2554,9 +2554,9 @@ static void fill_audio_info(struct audio_info *audio_info, cea_revision = drm_connector->display_info.cea_rev; - strncpy(audio_info->display_name, + strscpy(audio_info->display_name, edid_caps->display_name, - AUDIO_INFO_DISPLAY_NAME_SIZE_IN_CHARS - 1); + AUDIO_INFO_DISPLAY_NAME_SIZE_IN_CHARS); if (cea_revision >= 3) { audio_info->mode_count = edid_caps->audio_mode_count; @@ -3652,7 +3652,7 @@ amdgpu_dm_create_common_mode(struct drm_encoder *encoder, mode->hdisplay = hdisplay; mode->vdisplay = vdisplay; mode->type &= ~DRM_MODE_TYPE_PREFERRED; - strncpy(mode->name, name, DRM_DISPLAY_MODE_LEN); + strscpy(mode->name, name, DRM_DISPLAY_MODE_LEN); return mode;