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/linux-3.5.y-queue
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
------
>From c0614f3697a7cbaa3ef53b8ef64866797e5112c0 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Wed, 16 Oct 2013 11:22:44 +0100
Subject: drm: Prevent overwriting from userspace underallocating core ioctl
structs
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commit b062672e305ce071f21eb9e18b102c2a430e0999 upstream.
Apply the protections from
commit 1b2f1489633888d4a06028315dc19d65768a1c05
Author: Dave Airlie <airlied@xxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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
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