linux-kernel - [PATCH 1/6] ptrace: move clearing of TIF_SYSCALL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190228183220.15626-2-sudeep.holla@arm.com>
Date:   Thu, 28 Feb 2019 18:32:15 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     x86@...nel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Oleg Nesterov <oleg@...hat.com>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Richard Weinberger <richard@....at>, jdike@...toit.com,
        Steve Capper <Steve.Capper@....com>,
        Haibo Xu <haibo.xu@....com>, Bin Lu <bin.lu@....com>
Subject: [PATCH 1/6] ptrace: move clearing of TIF_SYSCALL_EMU flag to core

While the TIF_SYSCALL_EMU is set in ptrace_resume independent of any
architecture, currently only powerpc and x86 unset the TIF_SYSCALL_EMU
flag in ptrace_disable which gets called from ptrace_detach.

Let's move the clearing of TIF_SYSCALL_EMU flag to ptrace_detach after
we return from ptrace_disable to ensure there's no change in the flow.

Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 arch/powerpc/kernel/ptrace.c | 1 -
 arch/x86/kernel/ptrace.c     | 3 ---
 kernel/ptrace.c              | 4 ++++
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index cdd5d1d3ae41..cb7e1439cafb 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -2508,7 +2508,6 @@ void ptrace_disable(struct task_struct *child)
 {
 	/* make sure the single step bit is not set. */
 	user_disable_single_step(child);
-	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 }
 
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 4b8ee05dd6ad..45792dbd2443 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -746,9 +746,6 @@ static int ioperm_get(struct task_struct *target,
 void ptrace_disable(struct task_struct *child)
 {
 	user_disable_single_step(child);
-#ifdef TIF_SYSCALL_EMU
-	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
-#endif
 }
 
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 771e93f9c43f..4fa3b7f4c3c7 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -534,6 +534,10 @@ static int ptrace_detach(struct task_struct *child, unsigned int data)
 	/* Architecture-specific hardware disable .. */
 	ptrace_disable(child);
 
+#ifdef TIF_SYSCALL_EMU
+	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+#endif
+
 	write_lock_irq(&tasklist_lock);
 	/*
 	 * We rely on ptrace_freeze_traced(). It can't be killed and
-- 
2.17.1