[PATCH 4.19 50/61] arm64: use the correct function type for __arm64_sys_ni_syscall

From: Greg Kroah-Hartman
Date: Thu Jun 20 2019 - 14:21:46 EST


[ Upstream commit 1e29ab3186e33c77dbb2d7566172a205b59fa390 ]

Calling sys_ni_syscall through a syscall_fn_t pointer trips indirect
call Control-Flow Integrity checking due to a function type
mismatch. Use SYSCALL_DEFINE0 for __arm64_sys_ni_syscall instead and
remove the now unnecessary casts.

Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/arm64/kernel/sys.c | 14 +++++++++-----
arch/arm64/kernel/sys32.c | 7 ++-----
2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index 162a95ed0881..fe20c461582a 100644
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -47,22 +47,26 @@ SYSCALL_DEFINE1(arm64_personality, unsigned int, personality)
return ksys_personality(personality);
}

+asmlinkage long sys_ni_syscall(void);
+
+asmlinkage long __arm64_sys_ni_syscall(const struct pt_regs *__unused)
+{
+ return sys_ni_syscall();
+}
+
/*
* Wrappers to pass the pt_regs argument.
*/
#define __arm64_sys_personality __arm64_sys_arm64_personality

-asmlinkage long sys_ni_syscall(const struct pt_regs *);
-#define __arm64_sys_ni_syscall sys_ni_syscall
-
#undef __SYSCALL
#define __SYSCALL(nr, sym) asmlinkage long __arm64_##sym(const struct pt_regs *);
#include <asm/unistd.h>

#undef __SYSCALL
-#define __SYSCALL(nr, sym) [nr] = (syscall_fn_t)__arm64_##sym,
+#define __SYSCALL(nr, sym) [nr] = __arm64_##sym,

const syscall_fn_t sys_call_table[__NR_syscalls] = {
- [0 ... __NR_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
+ [0 ... __NR_syscalls - 1] = __arm64_sys_ni_syscall,
#include <asm/unistd.h>
};
diff --git a/arch/arm64/kernel/sys32.c b/arch/arm64/kernel/sys32.c
index 0f8bcb7de700..3c80a40c1c9d 100644
--- a/arch/arm64/kernel/sys32.c
+++ b/arch/arm64/kernel/sys32.c
@@ -133,17 +133,14 @@ COMPAT_SYSCALL_DEFINE6(aarch32_fallocate, int, fd, int, mode,
return ksys_fallocate(fd, mode, arg_u64(offset), arg_u64(len));
}

-asmlinkage long sys_ni_syscall(const struct pt_regs *);
-#define __arm64_sys_ni_syscall sys_ni_syscall
-
#undef __SYSCALL
#define __SYSCALL(nr, sym) asmlinkage long __arm64_##sym(const struct pt_regs *);
#include <asm/unistd32.h>

#undef __SYSCALL
-#define __SYSCALL(nr, sym) [nr] = (syscall_fn_t)__arm64_##sym,
+#define __SYSCALL(nr, sym) [nr] = __arm64_##sym,

const syscall_fn_t compat_sys_call_table[__NR_compat_syscalls] = {
- [0 ... __NR_compat_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
+ [0 ... __NR_compat_syscalls - 1] = __arm64_sys_ni_syscall,
#include <asm/unistd32.h>
};
--
2.20.1