efi/x86: Mark kernel rodata non-executable for mixed mode

commit c8502eb2d43b6b9b1dc382299a4d37031be63876 upstream.

When remapping the kernel rodata section RO in the EFI pagetables, the
protection flags that were used for the text section are being reused,
but the rodata section should not be marked executable.

Cc: <stable@vger.kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200717194526.3452089-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 8e364c4c676837382b2d9b86f6ab132a9e92eb72..7caa6583735630f4fcf8c7584a44f312350343e9 100644 (file)
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -268,6 +268,8 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
        npages = (__end_rodata - __start_rodata) >> PAGE_SHIFT;
        rodata = __pa(__start_rodata);
        pfn = rodata >> PAGE_SHIFT;
+
+       pf = _PAGE_NX | _PAGE_ENC;
        if (kernel_map_pages_in_pgd(pgd, pfn, rodata, npages, pf)) {
                pr_err("Failed to map kernel rodata 1:1\n");
                return 1;