x86_64: ia32 ptrace THREAD_AREA fix (fd181c72) · Commits · 戴 / test

The addr argument to PTRACE_GET_THREAD_AREA and PTRACE_SET_THREAD_AREA is not a magic constant. It's derived from the segment register values being used, which are computed originally from the index used with set_thread_area. The value does not need to match what a native i386 kernel would accept. It needs to match the segment selectors that can actually be in use in this 32-bit process. The 64-bit ptrace support for PTRACE_GET_THREAD_AREA (normally used only on 32-bit processes) is correct, but the 32-bit emulation of ptrace is broken. Signed-off-by:

Roland McGrath <roland@redhat.com> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

arch/x86/ia32/ptrace32.c

+2 −8

Original line number	Diff line number	Diff line
		@@ -228,8 +228,6 @@ static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
		return ret;
		}

		#define COMPAT_GDT_ENTRY_TLS_MIN 6

		asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
		{
		struct task_struct *child;
		@@ -248,6 +246,8 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
		case PTRACE_SYSCALL:
		case PTRACE_OLDSETOPTIONS:
		case PTRACE_SETOPTIONS:
		case PTRACE_SET_THREAD_AREA:
		case PTRACE_GET_THREAD_AREA:
		return sys_ptrace(request, pid, addr, data);

		default:
		@@ -271,12 +271,6 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
		case PTRACE_SETSIGINFO:
		case PTRACE_GETSIGINFO:
		return ptrace32_siginfo(request, pid, addr, data);

		case PTRACE_SET_THREAD_AREA:
		case PTRACE_GET_THREAD_AREA:
		return sys_ptrace(request, pid,
		addr + GDT_ENTRY_TLS_MIN - COMPAT_GDT_ENTRY_TLS_MIN,
		data);
		}

		child = ptrace_get_task_struct(pid);

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