From: Roland McGrath Date: Tue, 6 Nov 2007 23:30:38 +0000 (-0800) Subject: x86_64: ia32 ptrace THREAD_AREA fix X-Git-Tag: v2.6.24-rc3~166 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fd181c72a3c202a3986bcee7551c0838265aec2a;p=linux-2.6 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 Signed-off-by: Thomas Gleixner --- diff --git a/arch/x86/ia32/ptrace32.c b/arch/x86/ia32/ptrace32.c index f52770ef0e..4a233ad626 100644 --- a/arch/x86/ia32/ptrace32.c +++ b/arch/x86/ia32/ptrace32.c @@ -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);