Commit 72aaf646 authored by Ashutosh Dixit's avatar Ashutosh Dixit Committed by Ben Hutchings

misc: mic: Fix for double fetch security bug in VOP driver

commit 9bf292bf upstream.

The MIC VOP driver does two successive reads from user space to read a
variable length data structure. Kernel memory corruption can result if
the data structure changes between the two reads. This patch disallows
the chance of this happening.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116651
Reported by: Pengfei Wang <wpengfeinudt@gmail.com>
Reviewed-by: default avatarSudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: default avatarAshutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16:
 - Adjust filename, context
 - goto exit on failure]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent c6287499
...@@ -456,6 +456,11 @@ static int mic_copy_dp_entry(struct mic_vdev *mvdev, ...@@ -456,6 +456,11 @@ static int mic_copy_dp_entry(struct mic_vdev *mvdev,
__func__, __LINE__, ret); __func__, __LINE__, ret);
goto exit; goto exit;
} }
/* Ensure desc has not changed between the two reads */
if (memcmp(&dd, dd_config, sizeof(dd))) {
ret = -EINVAL;
goto exit;
}
vqconfig = mic_vq_config(dd_config); vqconfig = mic_vq_config(dd_config);
for (i = 0; i < dd.num_vq; i++) { for (i = 0; i < dd.num_vq; i++) {
......
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