From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> stable inclusion from stable-v5.10.253 commit 46a60ee8956ef1975f00455f614761c7ecedc09d category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14531 CVE: CVE-2026-31781 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit f8995c2df519f382525ca4bc90553ad2ec611067 upstream. The drm compat ioctl path takes a user controlled pointer, and then dereferences it into a table of function pointers, the signature method of spectre problems. Fix this up by calling array_index_nospec() on the index to the function pointer list. Fixes: 505b5240329b ("drm/ioctl: Fix Spectre v1 vulnerabilities") Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: David Airlie <airlied@gmail.com> Cc: Simona Vetter <simona@ffwll.ch> Cc: stable <stable@kernel.org> Assisted-by: gkh_clanker_2000 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Maxime Ripard <mripard@kernel.org> Reviewed-by: Simona Vetter <simona@ffwll.ch> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Link: https://patch.msgid.link/2026032451-playing-rummage-8fa2@gregkh Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ziming Du <duziming2@huawei.com> --- drivers/gpu/drm/drm_ioc32.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c index ed20dbae66070..21236d06a3b67 100644 --- a/drivers/gpu/drm/drm_ioc32.c +++ b/drivers/gpu/drm/drm_ioc32.c @@ -28,6 +28,7 @@ * IN THE SOFTWARE. */ #include <linux/compat.h> +#include <linux/nospec.h> #include <linux/ratelimit.h> #include <linux/export.h> @@ -967,6 +968,7 @@ long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) if (nr >= ARRAY_SIZE(drm_compat_ioctls)) return drm_ioctl(filp, cmd, arg); + nr = array_index_nospec(nr, ARRAY_SIZE(drm_compat_ioctls)); fn = drm_compat_ioctls[nr].fn; if (!fn) return drm_ioctl(filp, cmd, arg); -- 2.43.0