From: Daniel Vetter daniel.vetter@ffwll.ch
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@kernel.org Reported-by: syzbot+620cf21140fc7e772a5d@syzkaller.appspotmail.com # vblank ioctl Cc: syzbot+620cf21140fc7e772a5d@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter daniel.vetter@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20210222100643.400935-1-daniel... (cherry picked from commit e926c474ebee404441c838d18224cd6f246a71b7) Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/drm_ioc32.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/drivers/gpu/drm/drm_ioc32.c b/drivers/gpu/drm/drm_ioc32.c index f8672238d444b..ab8847c7dd964 100644 --- a/drivers/gpu/drm/drm_ioc32.c +++ b/drivers/gpu/drm/drm_ioc32.c @@ -96,6 +96,8 @@ static int compat_drm_version(struct file *file, unsigned int cmd, 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), @@ -134,6 +136,9 @@ static int compat_drm_getunique(struct file *file, unsigned int cmd,
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), @@ -260,6 +265,8 @@ static int compat_drm_getclient(struct file *file, unsigned int cmd, 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, DRM_UNLOCKED); @@ -842,6 +849,8 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd, 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; @@ -879,6 +888,8 @@ static int compat_drm_mode_addfb2(struct file *file, unsigned int cmd, 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;