Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fd181c72 authored by Roland McGrath's avatar Roland McGrath Committed by Thomas Gleixner
Browse files

x86_64: ia32 ptrace THREAD_AREA fix 



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: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 1a0c3ea6

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);