| Date | Tue, 24 Aug 2010 15:45:42 -0700 | From | Greg KH <> | Subject | [097/114] drm: stop information leak of old kernel stack. |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Dave Airlie <airlied@redhat.com>
commit b9f0aee83335db1f3915f4e42a5e21b351740afd upstream.
non-critical issue, CVE-2010-2803
Userspace controls the amount of memory to be allocate, so it can get the ioctl to allocate more memory than the kernel uses, and get access to kernel stack. This can only be done for processes authenticated to the X server for DRI access, and if the user has DRI access.
Fix is to just memset the data to 0 if the user doesn't copy into it in the first place.
Reported-by: Kees Cook <kees@ubuntu.com> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/gpu/drm/drm_drv.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -502,7 +502,9 @@ long drm_ioctl(struct file *filp, retcode = -EFAULT; goto err_i1; } - } + } else + memset(kdata, 0, _IOC_SIZE(cmd)); + if (ioctl->flags & DRM_UNLOCKED) retcode = func(dev, kdata, file_priv); else {
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