[PATCH AUTOSEL 5.4 099/350] syscalls/x86: Use the correct function type in SYSCALL_DEFINE0

Sasha Levin
2019-12-10T21:48:42Z

From: Sami Tolvanen <samitolvanen@google.com>

[ Upstream commit 8661d769ab77c675b5eb6c3351a372b9fbc1bf40 ]

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid type mismatches
with Control-Flow Integrity (CFI) checking.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H . Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191008224049.115427-2-samitolvanen@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/include/asm/syscall_wrapper.h | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index e046a405743d8..90eb70df0b18d 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -48,12 +48,13 @@
* To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias
* named __ia32_sys_*()
*/
-#define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- asmlinkage long __x64_sys_##sname(void); \
- ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
- SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \
- asmlinkage long __x64_sys_##sname(void)
+
+#define SYSCALL_DEFINE0(sname) \
+ SYSCALL_METADATA(_##sname, 0); \
+ asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\
+ ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
+ SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \
+ asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused)

#define COND_SYSCALL(name) \
cond_syscall(__x64_sys_##name); \
@@ -181,11 +182,11 @@
* macros to work correctly.
*/
#ifndef SYSCALL_DEFINE0
-#define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- asmlinkage long __x64_sys_##sname(void); \
- ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
- asmlinkage long __x64_sys_##sname(void)
+#define SYSCALL_DEFINE0(sname) \
+ SYSCALL_METADATA(_##sname, 0); \
+ asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\
+ ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
+ asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused)
#endif

#ifndef COND_SYSCALL
--
2.20.1