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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: Roland McGrath <roland@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath 2007-11-06 15:30:38 -08:00 committed by Thomas Gleixner
parent 1a0c3ea65c
commit fd181c72a3
1 changed files with 2 additions and 8 deletions
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10
arch/x86/ia32/ptrace32.c
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@ -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);