On Sun, 04 Oct 2020 19:41:20 -0500, Jarkko Sakkinen
<jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
Fix the issue further discussed in:
1.
https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
2.
https://lore.kernel.org/linux-sgx/20201003195440.GD20115@xxxxxxxxxxxxxxxxxxxx/
Reported-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: Jethro Beekman <jethro@xxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
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
