Commit 61f25982 authored by Tony Luck's avatar Tony Luck Committed by Doug Ledford
Browse files

IB/core: Add mitigation for Spectre V1 



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


Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 708637e6

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 <linux/uaccess.h>
@@ -884,11 +885,14 @@ 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;

	}