This is a note to let you know that I have just added a patch titled

drm: Prevent overwriting from userspace underallocating core ioctl

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at:

http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linu...

If you, or anyone else, feels it should not be added to this tree, please reply to this email.

For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks. -Luis

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From c0614f3697a7cbaa3ef53b8ef64866797e5112c0 Mon Sep 17 00:00:00 2001

From: Chris Wilson chris@chris-wilson.co.uk 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 airlied@redhat.com 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 chris@chris-wilson.co.uk Cc: Dave Airlie airlied@redhat.com Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: Dave Airlie airlied@redhat.com [ luis: backported to 3.5: adjusted context ] Signed-off-by: Luis Henriques luis.henriques@canonical.com --- 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 8a9d079..df54da9 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -422,9 +422,16 @@ long drm_ioctl(struct file *filp, asize = drv_size; } 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;

-- 1.8.3.2