Commit f53e2cd0 authored Sep 13, 2019 by Sami Tolvanen Committed by Ingo Molnar Oct 11, 2019

x86/mm: Use the correct function type for native_set_fixmap()



We call native_set_fixmap indirectly through the function pointer
struct pv_mmu_ops::set_fixmap, which expects the first parameter to be
'unsigned' instead of 'enum fixed_addresses'. This patch changes the
function type for native_set_fixmap to match the pointer, which fixes
indirect call mismatches with Control-Flow Integrity (CFI) checking.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H . Peter Anvin <hpa@zytor.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190913211402.193018-1-samitolvanen@google.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 6e484764

arch/x86/include/asm/fixmap.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -156,7 +156,7 @@ extern pte_t *kmap_pte;
		extern pte_t *pkmap_page_table;

		void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
		void native_set_fixmap(enum fixed_addresses idx,
		void native_set_fixmap(unsigned /* enum fixed_addresses */ idx,
		phys_addr_t phys, pgprot_t flags);

		#ifndef CONFIG_PARAVIRT_XXL

arch/x86/mm/pgtable.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -643,8 +643,8 @@ void __native_set_fixmap(enum fixed_addresses idx, pte_t pte)
		fixmaps_set++;
		}

		void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
		pgprot_t flags)
		void native_set_fixmap(unsigned /* enum fixed_addresses */ idx,
		phys_addr_t phys, pgprot_t flags)
		{
		/* Sanitize 'prot' against any unsupported bits: */
		pgprot_val(flags) &= __default_kernel_pte_mask;

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