mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-05 00:20:32 +00:00
drm/ioctl: Fix Spectre v1 vulnerabilities
commit 505b524032
upstream.
nr is indirectly controlled by user-space, hence leading to a
potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
drivers/gpu/drm/drm_ioctl.c:805 drm_ioctl() warn: potential spectre issue 'dev->driver->ioctls' [r]
drivers/gpu/drm/drm_ioctl.c:810 drm_ioctl() warn: potential spectre issue 'drm_ioctls' [r] (local cap)
drivers/gpu/drm/drm_ioctl.c:892 drm_ioctl_flags() warn: potential spectre issue 'drm_ioctls' [r] (local cap)
Fix this by sanitizing nr before using it to index dev->driver->ioctls
and drm_ioctls.
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181220000015.GA18973@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
6bb4132116
commit
7f3ebea197
1 changed files with 8 additions and 2 deletions
|
@ -37,6 +37,7 @@
|
|||
|
||||
#include <linux/pci.h>
|
||||
#include <linux/export.h>
|
||||
#include <linux/nospec.h>
|
||||
|
||||
/**
|
||||
* DOC: getunique and setversion story
|
||||
|
@ -794,13 +795,17 @@ long drm_ioctl(struct file *filp,
|
|||
|
||||
if (is_driver_ioctl) {
|
||||
/* driver ioctl */
|
||||
if (nr - DRM_COMMAND_BASE >= dev->driver->num_ioctls)
|
||||
unsigned int index = nr - DRM_COMMAND_BASE;
|
||||
|
||||
if (index >= dev->driver->num_ioctls)
|
||||
goto err_i1;
|
||||
ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE];
|
||||
index = array_index_nospec(index, dev->driver->num_ioctls);
|
||||
ioctl = &dev->driver->ioctls[index];
|
||||
} else {
|
||||
/* core ioctl */
|
||||
if (nr >= DRM_CORE_IOCTL_COUNT)
|
||||
goto err_i1;
|
||||
nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
|
||||
ioctl = &drm_ioctls[nr];
|
||||
}
|
||||
|
||||
|
@ -882,6 +887,7 @@ bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
|
|||
|
||||
if (nr >= DRM_CORE_IOCTL_COUNT)
|
||||
return false;
|
||||
nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
|
||||
|
||||
*flags = drm_ioctls[nr].flags;
|
||||
return true;
|
||||
|
|
Loading…
Reference in a new issue