[PATCH AUTOSEL 4.19 051/177] syscalls/x86: Use COMPAT_SYSCALL_DEFINE0 for IA32 (rt_)sigreturn

Sasha Levin
2019-12-10T21:44:32Z

From: Sami Tolvanen <samitolvanen@google.com>

[ Upstream commit 00198a6eaf66609de5e4de9163bb42c7ca9dd7b7 ]

Use COMPAT_SYSCALL_DEFINE0 to define (rt_)sigreturn() syscalls to
replace sys32_sigreturn() and sys32_rt_sigreturn(). This fixes indirect
call 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/20191008224049.115427-4-samitolvanen@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/entry/syscalls/syscall_32.tbl | 4 ++--
arch/x86/ia32/ia32_signal.c | 5 +++--
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 3cf7b533b3d13..273e99c0b9110 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -130,7 +130,7 @@
116 i386 sysinfo sys_sysinfo __ia32_compat_sys_sysinfo
117 i386 ipc sys_ipc __ia32_compat_sys_ipc
118 i386 fsync sys_fsync __ia32_sys_fsync
-119 i386 sigreturn sys_sigreturn sys32_sigreturn
+119 i386 sigreturn sys_sigreturn __ia32_compat_sys_sigreturn
120 i386 clone sys_clone __ia32_compat_sys_x86_clone
121 i386 setdomainname sys_setdomainname __ia32_sys_setdomainname
122 i386 uname sys_newuname __ia32_sys_newuname
@@ -184,7 +184,7 @@
170 i386 setresgid sys_setresgid16 __ia32_sys_setresgid16
171 i386 getresgid sys_getresgid16 __ia32_sys_getresgid16
172 i386 prctl sys_prctl __ia32_sys_prctl
-173 i386 rt_sigreturn sys_rt_sigreturn sys32_rt_sigreturn
+173 i386 rt_sigreturn sys_rt_sigreturn __ia32_compat_sys_rt_sigreturn
174 i386 rt_sigaction sys_rt_sigaction __ia32_compat_sys_rt_sigaction
175 i386 rt_sigprocmask sys_rt_sigprocmask __ia32_sys_rt_sigprocmask
176 i386 rt_sigpending sys_rt_sigpending __ia32_compat_sys_rt_sigpending
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 513ba49c204fe..35ddf2c9848c6 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -21,6 +21,7 @@
#include <linux/personality.h>
#include <linux/compat.h>
#include <linux/binfmts.h>
+#include <linux/syscalls.h>
#include <asm/ucontext.h>
#include <linux/uaccess.h>
#include <asm/fpu/internal.h>
@@ -118,7 +119,7 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
return err;
}

-asmlinkage long sys32_sigreturn(void)
+COMPAT_SYSCALL_DEFINE0(sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
@@ -144,7 +145,7 @@ asmlinkage long sys32_sigreturn(void)
return 0;
}

-asmlinkage long sys32_rt_sigreturn(void)
+COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe_ia32 __user *frame;
--
2.20.1