drm_get_format_name() de-references the buf parameter without checking
if the pointer was not NULL. Given that the function is EXPORT-ed, lets
sanitise the parameters before proceeding.
v2: Use BUG_ON() to annoy users that did not pass valid parameters to function.
Fixes: b3c11ac267d461d3d5 ("drm: move allocation out of drm_get_format_name())
Cc: Eric Engestrom <e...@engestrom.ch>
Cc: Rob Clark <robdcl...@gmail.com>
Cc: Jani Nikula <jani.nik...@intel.com>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Signed-off-by: Liviu Dudau <liviu.du...@arm.com>
---
I still think sanity checking the parameters of an exported function is worth
doing, even if the way one triggers the NULL pointer crash is priviledged. Not
a big fan of the verbosity of BUG_ON() and would rather silently reject NULL buf
pointer, but that is a matter of taste.
drivers/gpu/drm/drm_fourcc.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index 90d2cc8..6d80239 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -85,6 +85,8 @@ EXPORT_SYMBOL(drm_mode_legacy_fb_format);
*/
const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf
*buf)
{
+ BUG_ON(!buf);
+
snprintf(buf->str, sizeof(buf->str),
"%c%c%c%c %s-endian (0x%08x)",
printable_char(format & 0xff),
--
2.10.2
