From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> From: Daniel Vetter <daniel.vetter@xxxxxxxx> commit de066e116306baf3a6a62691ac63cfc0b1dabddb upstream. Some of them have gaps, or fields we don't clear. Native ioctl code does full copies plus zero-extends on size mismatch, so nothing can leak. But compat is more hand-rolled so need to be careful. None of these matter for performance, so just memset. Also I didn't fix up the CONFIG_DRM_LEGACY or CONFIG_DRM_AGP ioctl, those are security holes anyway. Acked-by: Maxime Ripard <mripard@xxxxxxxxxx> Reported-by: syzbot+620cf21140fc7e772a5d@xxxxxxxxxxxxxxxxxxxxxxxxx # vblank ioctl Cc: syzbot+620cf21140fc7e772a5d@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20210222100643.400935-1-daniel.vetter@xxxxxxxx (cherry picked from commit e926c474ebee404441c838d18224cd6f246a71b7) Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/drm_ioc32.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/gpu/drm/drm_ioc32.c +++ b/drivers/gpu/drm/drm_ioc32.c @@ -99,6 +99,8 @@ static int compat_drm_version(struct fil if (copy_from_user(&v32, (void __user *)arg, sizeof(v32))) return -EFAULT; + memset(&v, 0, sizeof(v)); + v = (struct drm_version) { .name_len = v32.name_len, .name = compat_ptr(v32.name), @@ -137,6 +139,9 @@ static int compat_drm_getunique(struct f if (copy_from_user(&uq32, (void __user *)arg, sizeof(uq32))) return -EFAULT; + + memset(&uq, 0, sizeof(uq)); + uq = (struct drm_unique){ .unique_len = uq32.unique_len, .unique = compat_ptr(uq32.unique), @@ -265,6 +270,8 @@ static int compat_drm_getclient(struct f if (copy_from_user(&c32, argp, sizeof(c32))) return -EFAULT; + memset(&client, 0, sizeof(client)); + client.idx = c32.idx; err = drm_ioctl_kernel(file, drm_getclient, &client, 0); @@ -852,6 +859,8 @@ static int compat_drm_wait_vblank(struct if (copy_from_user(&req32, argp, sizeof(req32))) return -EFAULT; + memset(&req, 0, sizeof(req)); + req.request.type = req32.request.type; req.request.sequence = req32.request.sequence; req.request.signal = req32.request.signal; @@ -889,6 +898,8 @@ static int compat_drm_mode_addfb2(struct struct drm_mode_fb_cmd2 req64; int err; + memset(&req64, 0, sizeof(req64)); + if (copy_from_user(&req64, argp, offsetof(drm_mode_fb_cmd232_t, modifier))) return -EFAULT;
