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 c5e393f8bb3f6363f47d94f42465155a2e333179..3b0a84c88b7d99404834b05b7e2e0f7c67a84311 100644 (file)
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -269,6 +269,8 @@ 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;