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IB/hfi1: Fix Spectre v1 vulnerability

PATCH Applied Gustavo A. R. Silva 2 participants 2 messages Jul 31, 2019 – Aug 1, 2019

Subsystems (2)
InfiniBand HFI1 driver
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Gustavo A. R. Silva

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#0 lore raw

PATCH 1/1 IB/hfi1: Fix Spectre v1 vulnerability

sl is controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.

Fix this by sanitizing sl before using it to index ibp->sl_to_sc.

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://lore.kernel.org/lkml/[email protected]/

Cc [email protected]
Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/infiniband/hw/hfi1/verbs.c | 2 ++
 1 file changed, 2 insertions(+)
drivers/infiniband/hw/hfi1/verbs.c +2 -0
index f4ca436118ab..9f53f63b1453 100644
@@ -54,6 +54,7 @@
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
 #include <rdma/opa_addr.h>
+#include <linux/nospec.h>
 
 #include "hfi.h"
 #include "common.h"

@@ -1537,6 +1538,7 @@ static int hfi1_check_ah(struct ib_device *ibdev, struct rdma_ah_attr *ah_attr)
 	sl = rdma_ah_get_sl(ah_attr);
 	if (sl >= ARRAY_SIZE(ibp->sl_to_sc))
 		return -EINVAL;
+	sl = array_index_nospec(sl, ARRAY_SIZE(ibp->sl_to_sc));
 
 	sc5 = ibp->sl_to_sc[sl];
 	if (sc_to_vlt(dd, sc5) > num_vls && sc_to_vlt(dd, sc5) != 0xf)
Signature · 1 line
2.22.0
Applied
#1 lore raw
Quoted 9 lines · Gustavo A. R. Silva

sl is controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.

Fix this by sanitizing sl before using it to index ibp->sl_to_sc.

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].

Quoted 6 lines

[1]
https://lore.kernel.org/lkml/[email protected]/

Cc [email protected]
Signed-off-by Gustavo A. R. Silva <[email protected]>

---

Thanks, applied to for-rc.

Signature · 3 lines
Doug Ledford <[email protected]>
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