From: Andy Lutomirski Date: Wed, 25 Feb 2015 00:01:38 +0000 (-0800) Subject: x86/ptrace: Remove checks for TIF_IA32 when changing CS and SS X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=08571f1ae327bfb631cb7171bde5ea605df626c6;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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: Andy Lutomirski Cc: Borislav Petkov Cc: Denys Vlasenko Link: http://lkml.kernel.org/r/71c7ab36456855d11ae07edd4945a7dfe80f9915.1424822291.git.luto@amacapital.net Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index e510618b2e91..1e125817cf9f 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -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 + task_pt_regs(task)->cs = value; 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 + task_pt_regs(task)->ss = value; break; }