From ed1e7db33c3354e4f8b594738c5e793690213b43 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov <0x7f454c46@gmail.com> Date: Thu, 20 Oct 2016 00:53:08 +0300 Subject: [PATCH] x86/signal: Remove bogus user_64bit_mode() check from sigaction_compat_abi() The recent introduction of SA_X32/IA32 sa_flags added a check for user_64bit_mode() into sigaction_compat_abi(). user_64bit_mode() is true for native 64-bit processes and x32 processes. Due to that the function returns w/o setting the SA_X32_ABI flag for X32 processes. In consequence the kernel attempts to deliver the signal to the X32 process in native 64-bit mode causing the process to segfault. Remove the check, so the actual check for X32 mode which sets the ABI flag can be reached. There is no side effect for native 64-bit mode. [ tglx: Rewrote changelog ] Fixes: 6846351052e6 ("x86/signal: Add SA_{X32,IA32}_ABI sa_flags") Reported-by: Mikulas Patocka Tested-by: Adam Borowski Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Dmitry Safonov Cc: Oleg Nesterov Cc: linux-mm@kvack.org Cc: Cyrill Gorcunov Cc: Pavel Emelyanov Link: http://lkml.kernel.org/r/CAJwJo6Z8ZWPqNfT6t-i8GW1MKxQrKDUagQqnZ%2B0%2B697%3DMyVeGg@mail.gmail.com Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/kernel/signal_compat.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c index 40df33753bae..ec1f756f9dc9 100644 --- a/arch/x86/kernel/signal_compat.c +++ b/arch/x86/kernel/signal_compat.c @@ -105,9 +105,6 @@ void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact) /* Don't let flags to be set from userspace */ act->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI); - if (user_64bit_mode(current_pt_regs())) - return; - if (in_ia32_syscall()) act->sa.sa_flags |= SA_IA32_ABI; if (in_x32_syscall()) -- 2.20.1