From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Haitao Huang <haitao.huang@linux.intel.com>
Cc: linux-sgx@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
Jethro Beekman <jethro@fortanix.com>,
Matthew Wilcox <willy@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH] x86/sgx: Fix sgx_encl_may_map locking
Date: Mon, 5 Oct 2020 06:43:53 +0300 [thread overview]
Message-ID: <20201005034353.GA159163@linux.intel.com> (raw)
In-Reply-To: <op.0rzvwhr9wjvjmi@mqcpg7oapc828.gar.corp.intel.com>
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
prev parent reply other threads:[~2020-10-05 3:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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