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; } -- 2.25.1
