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Commit 08571f1a authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/ptrace: Remove checks for TIF_IA32 when changing CS and SS 



The ability for modified CS and/or SS to be useful has nothing
to do with TIF_IA32.  Similarly, if there's an exploit involving
changing CS or SS, it's exploitable with or without a TIF_IA32
check.

So just delete the check.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Link: http://lkml.kernel.org/r/71c7ab36456855d11ae07edd4945a7dfe80f9915.1424822291.git.luto@amacapital.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 719d359d

arch/x86/kernel/ptrace.c

+2 −8
Original line number Diff line number Diff line
@@ -364,18 +364,12 @@ static int set_segment_reg(struct task_struct *task, 
	case offsetof(struct user_regs_struct,cs):

		if (unlikely(value == 0))

			return -EIO;

#ifdef CONFIG_IA32_EMULATION

		if (test_tsk_thread_flag(task, TIF_IA32))

		task_pt_regs(task)->cs = value;

#endif

		break;

	case offsetof(struct user_regs_struct,ss):

		if (unlikely(value == 0))

			return -EIO;

#ifdef CONFIG_IA32_EMULATION

		if (test_tsk_thread_flag(task, TIF_IA32))

		task_pt_regs(task)->ss = value;

#endif

		break;

	}