* [PATCH] x86/sgx: Allow RW for TCS pages
@ 2022-03-19 16:30 Jarkko Sakkinen
2022-03-28 20:28 ` Reinette Chatre
0 siblings, 1 reply; 3+ messages in thread
From: Jarkko Sakkinen @ 2022-03-19 16:30 UTC (permalink / raw)
To: linux-sgx
Cc: Jarkko Sakkinen, Dave Hansen, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
H. Peter Anvin, open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)
Not allowing to set RW for added TCS pages leads only to a special case
to be handled in the user space run-time. Thus, allow permissions to be
set RW. Originally, it would have probably made more sense to check up
that the permissions are RW.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
arch/x86/kernel/cpu/sgx/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 83df20e3e633..f79761ad0400 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -215,7 +215,7 @@ static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
* CPU will silently overwrite the permissions as zero, which means
* that we need to validate it ourselves.
*/
- if (pt == SGX_SECINFO_TCS && perm)
+ if (pt == SGX_SECINFO_TCS && (perm != 0 || perm != (PROT_READ | PROT_WRITE)))
return -EINVAL;
if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
--
2.35.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/sgx: Allow RW for TCS pages
2022-03-19 16:30 [PATCH] x86/sgx: Allow RW for TCS pages Jarkko Sakkinen
@ 2022-03-28 20:28 ` Reinette Chatre
2022-03-30 15:07 ` Jarkko Sakkinen
0 siblings, 1 reply; 3+ messages in thread
From: Reinette Chatre @ 2022-03-28 20:28 UTC (permalink / raw)
To: Jarkko Sakkinen, linux-sgx
Cc: Dave Hansen, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), H. Peter Anvin,
open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)
Hi Jarkko,
On 3/19/2022 9:30 AM, Jarkko Sakkinen wrote:
> Not allowing to set RW for added TCS pages leads only to a special case
> to be handled in the user space run-time. Thus, allow permissions to be
> set RW. Originally, it would have probably made more sense to check up
> that the permissions are RW.
>
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> arch/x86/kernel/cpu/sgx/ioctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index 83df20e3e633..f79761ad0400 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -215,7 +215,7 @@ static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
> * CPU will silently overwrite the permissions as zero, which means
> * that we need to validate it ourselves.
> */
> - if (pt == SGX_SECINFO_TCS && perm)
> + if (pt == SGX_SECINFO_TCS && (perm != 0 || perm != (PROT_READ | PROT_WRITE)))
> return -EINVAL;
>
> if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
The comments above sgx_ioc_enclave_add_pages() seem to indicate that zero
permissions are required:
"A SECINFO for a TCS is required to always contain zero permissions because
CPU silently zeros them. Allowing anything else would cause a mismatch in
the measurement."
Reinette
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/sgx: Allow RW for TCS pages
2022-03-28 20:28 ` Reinette Chatre
@ 2022-03-30 15:07 ` Jarkko Sakkinen
0 siblings, 0 replies; 3+ messages in thread
From: Jarkko Sakkinen @ 2022-03-30 15:07 UTC (permalink / raw)
To: Reinette Chatre
Cc: linux-sgx, Dave Hansen, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
H. Peter Anvin, open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)
On Mon, Mar 28, 2022 at 01:28:39PM -0700, Reinette Chatre wrote:
> Hi Jarkko,
>
> On 3/19/2022 9:30 AM, Jarkko Sakkinen wrote:
> > Not allowing to set RW for added TCS pages leads only to a special case
> > to be handled in the user space run-time. Thus, allow permissions to be
> > set RW. Originally, it would have probably made more sense to check up
> > that the permissions are RW.
> >
> > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> > ---
> > arch/x86/kernel/cpu/sgx/ioctl.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> > index 83df20e3e633..f79761ad0400 100644
> > --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> > @@ -215,7 +215,7 @@ static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
> > * CPU will silently overwrite the permissions as zero, which means
> > * that we need to validate it ourselves.
> > */
> > - if (pt == SGX_SECINFO_TCS && perm)
> > + if (pt == SGX_SECINFO_TCS && (perm != 0 || perm != (PROT_READ | PROT_WRITE)))
> > return -EINVAL;
> >
> > if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
>
> The comments above sgx_ioc_enclave_add_pages() seem to indicate that zero
> permissions are required:
>
> "A SECINFO for a TCS is required to always contain zero permissions because
> CPU silently zeros them. Allowing anything else would cause a mismatch in
> the measurement."
I think this can be left out for now but fixing the relative addressing
is an obvious fix.
BR, Jarkko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-03-19 16:30 [PATCH] x86/sgx: Allow RW for TCS pages Jarkko Sakkinen
2022-03-28 20:28 ` Reinette Chatre
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