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Message-Id: <20190822171733.289701089@linuxfoundation.org>
Date: Thu, 22 Aug 2019 10:19:19 -0700
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Tony Luck <tony.luck@...el.com>,
Doug Ledford <dledford@...hat.com>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 46/85] 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@...el.com>
Link: https://lore.kernel.org/r/20190731043957.GA1600@agluck-desk2.amr.corp.intel.com
Signed-off-by: Doug Ledford <dledford@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/infiniband/core/user_mad.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index c34a6852d691f..a18f3f8ad77fe 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -49,6 +49,7 @@
#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/slab.h>
+#include <linux/nospec.h>
#include <linux/uaccess.h>
@@ -868,11 +869,14 @@ 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;
}
--
2.20.1
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