* [PATCH ] powerpc/pkeys: Detach execute_only key on !PROT_EXEC
@ 2018-05-04 20:01 Ram Pai
2018-05-22 1:42 ` Thiago Jung Bauermann
2018-06-05 15:19 ` Michael Ellerman
0 siblings, 2 replies; 3+ messages in thread
From: Ram Pai @ 2018-05-04 20:01 UTC (permalink / raw)
To: mpe
Cc: linuxppc-dev, benh, paulus, aneesh.kumar, bsingharora, hbabu,
mhocko, bauerman, linuxram, msuchanek, Ulrich.Weigand,
dave.hansen, Shakeel Butt
Disassociate the exec_key from a VMA if the VMA permission is not
PROT_EXEC anymore. Otherwise the exec_only key continues to be
associated with the vma, causing unexpected behavior.
The problem was reported on x86 by Shakeel Butt,
which is also applicable on powerpc.
cc: Shakeel Butt <shakeelb@google.com>
Reported-by: Shakeel Butt <shakeelb@google.com>
Fixes 5586cf6 ("powerpc: introduce execute-only pkey")
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
arch/powerpc/mm/pkeys.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index e81d59e..fdeb9f5 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -425,9 +425,9 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot,
{
/*
* If the currently associated pkey is execute-only, but the requested
- * protection requires read or write, move it back to the default pkey.
+ * protection is not execute-only, move it back to the default pkey.
*/
- if (vma_is_pkey_exec_only(vma) && (prot & (PROT_READ | PROT_WRITE)))
+ if (vma_is_pkey_exec_only(vma) && (prot != PROT_EXEC))
return 0;
/*
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH ] powerpc/pkeys: Detach execute_only key on !PROT_EXEC
2018-05-04 20:01 [PATCH ] powerpc/pkeys: Detach execute_only key on !PROT_EXEC Ram Pai
@ 2018-05-22 1:42 ` Thiago Jung Bauermann
2018-06-05 15:19 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Thiago Jung Bauermann @ 2018-05-22 1:42 UTC (permalink / raw)
To: Ram Pai
Cc: mpe, linuxppc-dev, benh, paulus, aneesh.kumar, bsingharora,
hbabu, mhocko, bauerman, msuchanek, Ulrich.Weigand, dave.hansen,
Shakeel Butt
Ram Pai <linuxram@us.ibm.com> writes:
> Disassociate the exec_key from a VMA if the VMA permission is not
> PROT_EXEC anymore. Otherwise the exec_only key continues to be
> associated with the vma, causing unexpected behavior.
>
> The problem was reported on x86 by Shakeel Butt,
> which is also applicable on powerpc.
>
> cc: Shakeel Butt <shakeelb@google.com>
> Reported-by: Shakeel Butt <shakeelb@google.com>
> Fixes 5586cf6 ("powerpc: introduce execute-only pkey")
^
Missing a colon here.
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
> arch/powerpc/mm/pkeys.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
> index e81d59e..fdeb9f5 100644
> --- a/arch/powerpc/mm/pkeys.c
> +++ b/arch/powerpc/mm/pkeys.c
> @@ -425,9 +425,9 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot,
> {
> /*
> * If the currently associated pkey is execute-only, but the requested
> - * protection requires read or write, move it back to the default pkey.
> + * protection is not execute-only, move it back to the default pkey.
> */
> - if (vma_is_pkey_exec_only(vma) && (prot & (PROT_READ | PROT_WRITE)))
> + if (vma_is_pkey_exec_only(vma) && (prot != PROT_EXEC))
> return 0;
>
> /*
I think I'm slow today. It took me a while to figure out why this is
buggy. It will leave the VMA with the execute-only pkey if prot = 0.
Other bit combinations work fine IIUC.
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
--
Thiago Jung Bauermann
IBM Linux Technology Center
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: powerpc/pkeys: Detach execute_only key on !PROT_EXEC
2018-05-04 20:01 [PATCH ] powerpc/pkeys: Detach execute_only key on !PROT_EXEC Ram Pai
2018-05-22 1:42 ` Thiago Jung Bauermann
@ 2018-06-05 15:19 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2018-06-05 15:19 UTC (permalink / raw)
To: Ram Pai
Cc: dave.hansen, msuchanek, Ulrich.Weigand, linuxram, mhocko, paulus,
aneesh.kumar, bauerman, Shakeel Butt, linuxppc-dev
On Fri, 2018-05-04 at 20:01:51 UTC, Ram Pai wrote:
> Disassociate the exec_key from a VMA if the VMA permission is not
> PROT_EXEC anymore. Otherwise the exec_only key continues to be
> associated with the vma, causing unexpected behavior.
>
> The problem was reported on x86 by Shakeel Butt,
> which is also applicable on powerpc.
>
> cc: Shakeel Butt <shakeelb@google.com>
> Reported-by: Shakeel Butt <shakeelb@google.com>
> Fixes 5586cf6 ("powerpc: introduce execute-only pkey")
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/eabdb8ca8690eedd461e61ea778059
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-05-04 20:01 [PATCH ] powerpc/pkeys: Detach execute_only key on !PROT_EXEC Ram Pai
2018-05-22 1:42 ` Thiago Jung Bauermann
2018-06-05 15:19 ` Michael Ellerman
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