Commit b88f8f19 authored Jul 30, 2019 by Tony Luck Committed by Greg Kroah-Hartman Aug 25, 2019

IB/core: Add mitigation for Spectre V1



[ Upstream commit 61f259821dd3306e49b7d42a3f90fb5a4ff3351b ]

Some processors may mispredict an array bounds check and
speculatively access memory that they should not. With
a user supplied array index we like to play things safe
by masking the value with the array size before it is
used as an index.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20190731043957.GA1600@agluck-desk2.amr.corp.intel.com


Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 81882762

drivers/infiniband/core/user_mad.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -49,6 +49,7 @@
		#include <linux/sched.h>
		#include <linux/semaphore.h>
		#include <linux/slab.h>
		#include <linux/nospec.h>

		#include <asm/uaccess.h>

		@@ -842,11 +843,14 @@ static int ib_umad_unreg_agent(struct ib_umad_file file, u32 __user arg)

		if (get_user(id, arg))
		return -EFAULT;
		if (id >= IB_UMAD_MAX_AGENTS)
		return -EINVAL;

		mutex_lock(&file->port->file_mutex);
		mutex_lock(&file->mutex);

		if (id >= IB_UMAD_MAX_AGENTS \|\| !__get_agent(file, id)) {
		id = array_index_nospec(id, IB_UMAD_MAX_AGENTS);
		if (!__get_agent(file, id)) {
		ret = -EINVAL;
		goto out;
		}