From: "Haitao Huang" <haitao.huang@linux.intel.com>
To: linux-sgx@vger.kernel.org,
"Jarkko Sakkinen" <jarkko.sakkinen@linux.intel.com>
Cc: "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: Sun, 04 Oct 2020 22:27:43 -0500 [thread overview]
Message-ID: <op.0rzvwhr9wjvjmi@mqcpg7oapc828.gar.corp.intel.com> (raw)
In-Reply-To: <20201005004120.105849-1-jarkko.sakkinen@linux.intel.com>
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
next prev parent reply other threads:[~2020-10-05 3:27 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 [this message]
2020-10-05 3:43 ` Jarkko Sakkinen
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