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From: Sami Tolvanen <samitolvanen@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Kees Cook <keescook@chromium.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH] x86: use the correct function type for native_set_fixmap
Date: Fri, 13 Sep 2019 14:14:02 -0700	[thread overview]
Message-ID: <20190913211402.193018-1-samitolvanen@google.com> (raw)

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>
---
 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 9da8cccdf3fb..6a295acd3de6 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -157,7 +157,7 @@ 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
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 44816ff6411f..d0ad35e3de74 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -647,8 +647,8 @@ 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;
-- 
2.23.0.237.gc6a4ce50a0-goog


             reply	other threads:[~2019-09-13 21:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-13 21:14 Sami Tolvanen [this message]
2019-09-23 23:27 ` [PATCH] x86: use the correct function type for native_set_fixmap Kees Cook
2019-09-24 19:51   ` Sami Tolvanen
2019-10-08 22:18     ` Sami Tolvanen
2019-10-11 11:22 ` [tip: x86/entry] x86/mm: Use the correct function type for native_set_fixmap() tip-bot2 for Sami Tolvanen

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