* [PATCH] x86/sgx: Fix sgx_encl_may_map locking
@ 2020-10-05 0:41 Jarkko Sakkinen
2020-10-05 3:27 ` Haitao Huang
0 siblings, 1 reply; 3+ messages in thread
From: Jarkko Sakkinen @ 2020-10-05 0:41 UTC (permalink / raw)
To: linux-sgx
Cc: Jarkko Sakkinen, Haitao Huang, Sean Christopherson,
Jethro Beekman, Matthew Wilcox, Dave Hansen
Fix the issue further discussed in:
1. https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@mqcpg7oapc828.gar.corp.intel.com/
2. https://lore.kernel.org/linux-sgx/20201003195440.GD20115@casper.infradead.org/
Reported-by: Haitao Huang <haitao.huang@linux.intel.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Jethro Beekman <jethro@fortanix.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index ae45f8f0951e..a225e96c7a39 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -304,11 +304,10 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
unsigned long end, unsigned long vm_flags)
{
unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC);
- unsigned long idx_start = PFN_DOWN(start);
- unsigned long idx_end = PFN_DOWN(end - 1);
+ unsigned long start_i = PFN_DOWN(start);
+ unsigned long end_i = PFN_DOWN(end - 1);
struct sgx_encl_page *page;
-
- XA_STATE(xas, &encl->page_array, idx_start);
+ int i;
/*
* Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might
@@ -317,9 +316,14 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
if (current->personality & READ_IMPLIES_EXEC)
return -EACCES;
- xas_for_each(&xas, page, idx_end)
+ for (i = start_i; i <= end_i; i++) {
+ mutex_lock(&encl->lock);
+ page = xa_load(&encl->page_array, i);
+ mutex_unlock(&encl->lock);
+
if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
return -EACCES;
+ }
return 0;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] x86/sgx: Fix sgx_encl_may_map locking
2020-10-05 0:41 [PATCH] x86/sgx: Fix sgx_encl_may_map locking Jarkko Sakkinen
@ 2020-10-05 3:27 ` Haitao Huang
2020-10-05 3:43 ` Jarkko Sakkinen
0 siblings, 1 reply; 3+ messages in thread
From: Haitao Huang @ 2020-10-05 3:27 UTC (permalink / raw)
To: linux-sgx, Jarkko Sakkinen
Cc: Sean Christopherson, Jethro Beekman, Matthew Wilcox, Dave Hansen
On Sun, 04 Oct 2020 19:41:20 -0500, Jarkko Sakkinen
<jarkko.sakkinen@linux.intel.com> wrote:
> Fix the issue further discussed in:
>
> 1.
> https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@mqcpg7oapc828.gar.corp.intel.com/
> 2.
> https://lore.kernel.org/linux-sgx/20201003195440.GD20115@casper.infradead.org/
>
> Reported-by: Haitao Huang <haitao.huang@linux.intel.com>
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Cc: Jethro Beekman <jethro@fortanix.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c
> b/arch/x86/kernel/cpu/sgx/encl.c
> index ae45f8f0951e..a225e96c7a39 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -304,11 +304,10 @@ int sgx_encl_may_map(struct sgx_encl *encl,
> unsigned long start,
> unsigned long end, unsigned long vm_flags)
> {
> unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC);
> - unsigned long idx_start = PFN_DOWN(start);
> - unsigned long idx_end = PFN_DOWN(end - 1);
> + unsigned long start_i = PFN_DOWN(start);
> + unsigned long end_i = PFN_DOWN(end - 1);
> struct sgx_encl_page *page;
> -
> - XA_STATE(xas, &encl->page_array, idx_start);
> + int i;
> /*
> * Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might
> @@ -317,9 +316,14 @@ int sgx_encl_may_map(struct sgx_encl *encl,
> unsigned long start,
> if (current->personality & READ_IMPLIES_EXEC)
> return -EACCES;
> - xas_for_each(&xas, page, idx_end)
> + for (i = start_i; i <= end_i; i++) {
> + mutex_lock(&encl->lock);
> + page = xa_load(&encl->page_array, i);
> + mutex_unlock(&encl->lock);
> +
> if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
> return -EACCES;
> + }
> return 0;
> }
Works with no PROVE_LOCKING complaints.
Haitao
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] x86/sgx: Fix sgx_encl_may_map locking
2020-10-05 3:27 ` Haitao Huang
@ 2020-10-05 3:43 ` Jarkko Sakkinen
0 siblings, 0 replies; 3+ messages in thread
From: Jarkko Sakkinen @ 2020-10-05 3:43 UTC (permalink / raw)
To: Haitao Huang
Cc: linux-sgx, Sean Christopherson, Jethro Beekman, Matthew Wilcox,
Dave Hansen
On Sun, Oct 04, 2020 at 10:27:43PM -0500, Haitao Huang wrote:
> On Sun, 04 Oct 2020 19:41:20 -0500, Jarkko Sakkinen
> <jarkko.sakkinen@linux.intel.com> wrote:
>
> > Fix the issue further discussed in:
> >
> > 1. https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@mqcpg7oapc828.gar.corp.intel.com/
> > 2. https://lore.kernel.org/linux-sgx/20201003195440.GD20115@casper.infradead.org/
> >
> > Reported-by: Haitao Huang <haitao.huang@linux.intel.com>
> > Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> > Cc: Jethro Beekman <jethro@fortanix.com>
> > Cc: Matthew Wilcox <willy@infradead.org>
> > Cc: Dave Hansen <dave.hansen@linux.intel.com>
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> > arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++++-----
> > 1 file changed, 9 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/encl.c
> > b/arch/x86/kernel/cpu/sgx/encl.c
> > index ae45f8f0951e..a225e96c7a39 100644
> > --- a/arch/x86/kernel/cpu/sgx/encl.c
> > +++ b/arch/x86/kernel/cpu/sgx/encl.c
> > @@ -304,11 +304,10 @@ int sgx_encl_may_map(struct sgx_encl *encl,
> > unsigned long start,
> > unsigned long end, unsigned long vm_flags)
> > {
> > unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC);
> > - unsigned long idx_start = PFN_DOWN(start);
> > - unsigned long idx_end = PFN_DOWN(end - 1);
> > + unsigned long start_i = PFN_DOWN(start);
> > + unsigned long end_i = PFN_DOWN(end - 1);
> > struct sgx_encl_page *page;
> > -
> > - XA_STATE(xas, &encl->page_array, idx_start);
> > + int i;
> > /*
> > * Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might
> > @@ -317,9 +316,14 @@ int sgx_encl_may_map(struct sgx_encl *encl,
> > unsigned long start,
> > if (current->personality & READ_IMPLIES_EXEC)
> > return -EACCES;
> > - xas_for_each(&xas, page, idx_end)
> > + for (i = start_i; i <= end_i; i++) {
> > + mutex_lock(&encl->lock);
> > + page = xa_load(&encl->page_array, i);
> > + mutex_unlock(&encl->lock);
> > +
> > if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
> > return -EACCES;
> > + }
> > return 0;
> > }
>
> Works with no PROVE_LOCKING complaints.
> Haitao
Great. That is a good reference point. Thank you.
v2 should work too but needs to be checked.
/Jarkko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-10-05 0:41 [PATCH] x86/sgx: Fix sgx_encl_may_map locking Jarkko Sakkinen
2020-10-05 3:27 ` Haitao Huang
2020-10-05 3:43 ` Jarkko Sakkinen
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