[PATCH 5.18 18/70] x86/vsyscall_emu/64: Dont use RET in vsyscall emulation

Greg Kroah-Hartman
2022-07-22T09:09:16Z

From: Peter Zijlstra <peterz@infradead.org>

commit 15583e514eb16744b80be85dea0774ece153177d upstream.

This is userspace code and doesn't play by the normal kernel rules.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/entry/vsyscall/vsyscall_emu_64.S | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/arch/x86/entry/vsyscall/vsyscall_emu_64.S
+++ b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
@@ -19,17 +19,20 @@ __vsyscall_page:

mov $__NR_gettimeofday, %rax
syscall
- RET
+ ret
+ int3

.balign 1024, 0xcc
mov $__NR_time, %rax
syscall
- RET
+ ret
+ int3

.balign 1024, 0xcc
mov $__NR_getcpu, %rax
syscall
- RET
+ ret
+ int3

.balign 4096, 0xcc