Re: [PATCH 4.14 38/53] IB/hfi1: Fix Spectre v1 vulnerability

[Gustavo A. R. Silva]

Hi Greg,

Can you please add these other two patches to stable:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d64062b57eeb58d4928aed945515bf53f7944913
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=737298d18836fd14b8820de6504536c998986bcd

Thanks!
--
Gustavo

On 8/5/19 8:03 AM, Greg Kroah-Hartman wrote:
> From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> 
> 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@xxxxxxxxxxxxxx/
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20190731175428.GA16736@embeddedor
> Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> ---
>  drivers/infiniband/hw/hfi1/verbs.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> --- a/drivers/infiniband/hw/hfi1/verbs.c
> +++ b/drivers/infiniband/hw/hfi1/verbs.c
> @@ -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"
> @@ -1587,6 +1588,7 @@ static int hfi1_check_ah(struct ib_devic
>  	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)
> 
>