[PATCH 4.4 026/137] x86/mm: Use the correct function type for native_set_fixmap()

Greg Kroah-Hartman
2020-01-02T22:42:31Z

From: Sami Tolvanen <samitolvanen@google.com>

[ Upstream commit f53e2cd0b8ab7d9e390414470bdbd830f660133f ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/include/asm/fixmap.h | 2 +-
arch/x86/mm/pgtable.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index f80d70009ff8..d0e39f54feee 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -147,7 +147,7 @@ extern pgprot_t kmap_prot;
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
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 50f75768aadd..3ed4753280aa 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -567,8 +567,8 @@ 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)
{
__native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
}
--
2.20.1