commit
6497d0a9c53df6e98b25e2b79f2295d7caa47b6e upstream.
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/
20180423164740.GY17484@dhcp22.suse.cz/
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20190731175428.GA16736@embeddedor
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <rdma/opa_addr.h>
+#include <linux/nospec.h>
#include "hfi.h"
#include "common.h"
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)