From 8528076a9922966b93b7b12e104cd3fdcd8fee3f Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 16 Oct 2013 11:22:44 +0100 Subject: drm: Prevent overwriting from userspace underallocating core ioctl structs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit b062672e305ce071f21eb9e18b102c2a430e0999 upstream. Apply the protections from commit 1b2f1489633888d4a06028315dc19d65768a1c05 Author: Dave Airlie Date: Sat Aug 14 20:20:34 2010 +1000 drm: block userspace under allocating buffer and having drivers overwrite it (v2) to the core ioctl structs as well, for we found one instance where there is a 32-/64-bit size mismatch and were guilty of writing beyond the end of the user's buffer. Signed-off-by: Chris Wilson Cc: Dave Airlie Reviewed-by: Ville Syrjälä Cc: dri-devel@lists.freedesktop.org Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_drv.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 99fcd7c32ea2..6dd71735cab4 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -407,9 +407,16 @@ long drm_ioctl(struct file *filp, cmd = ioctl->cmd_drv; } else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) { + u32 drv_size; + ioctl = &drm_ioctls[nr]; - cmd = ioctl->cmd; + + drv_size = _IOC_SIZE(ioctl->cmd); usize = asize = _IOC_SIZE(cmd); + if (drv_size > asize) + asize = drv_size; + + cmd = ioctl->cmd; } else goto err_i1; -- cgit v1.2.3