diff options
| author | Andi Kleen <ak@suse.de> | 2007-09-21 16:16:18 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-09-21 09:52:07 -0700 |
| commit | 176df2457ef6207156ca1a40991c54ca01fef567 (patch) | |
| tree | dddbc675ad695d1bae8f32a1c877b47c3a548a09 | |
| parent | 335fb8fc71692830aca0a5a5fe7f60016ee0d0aa (diff) | |
| download | linux-176df2457ef6207156ca1a40991c54ca01fef567.tar.bz2 | |
x86_64: Zero extend all registers after ptrace in 32bit entry path.
Strictly it's only needed for eax.
It actually does a little more than strictly needed -- the other registers
are already zero extended.
Also remove the now unnecessary and non functional compat task check
in ptrace.
This is CVE-2007-4573
Found by Wojciech Purczynski
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86_64/ia32/ia32entry.S | 18 | ||||
| -rw-r--r-- | arch/x86_64/kernel/ptrace.c | 4 |
2 files changed, 15 insertions, 7 deletions
diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S index 938278697e20..18b231810908 100644 --- a/arch/x86_64/ia32/ia32entry.S +++ b/arch/x86_64/ia32/ia32entry.S @@ -38,6 +38,18 @@ movq %rax,R8(%rsp) .endm + .macro LOAD_ARGS32 offset + movl \offset(%rsp),%r11d + movl \offset+8(%rsp),%r10d + movl \offset+16(%rsp),%r9d + movl \offset+24(%rsp),%r8d + movl \offset+40(%rsp),%ecx + movl \offset+48(%rsp),%edx + movl \offset+56(%rsp),%esi + movl \offset+64(%rsp),%edi + movl \offset+72(%rsp),%eax + .endm + .macro CFI_STARTPROC32 simple CFI_STARTPROC \simple CFI_UNDEFINED r8 @@ -152,7 +164,7 @@ sysenter_tracesys: movq $-ENOSYS,RAX(%rsp) /* really needed? */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */ + LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST movl %ebp, %ebp /* no need to do an access_ok check here because rbp has been @@ -255,7 +267,7 @@ cstar_tracesys: movq $-ENOSYS,RAX(%rsp) /* really needed? */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */ + LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST movl RSP-ARGOFFSET(%rsp), %r8d /* no need to do an access_ok check here because r8 has been @@ -334,7 +346,7 @@ ia32_tracesys: movq $-ENOSYS,RAX(%rsp) /* really needed? */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */ + LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST jmp ia32_do_syscall END(ia32_syscall) diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c index e83cc67155ac..eea3702427b4 100644 --- a/arch/x86_64/kernel/ptrace.c +++ b/arch/x86_64/kernel/ptrace.c @@ -232,10 +232,6 @@ static int putreg(struct task_struct *child, { unsigned long tmp; - /* Some code in the 64bit emulation may not be 64bit clean. - Don't take any chances. */ - if (test_tsk_thread_flag(child, TIF_IA32)) - value &= 0xffffffff; switch (regno) { case offsetof(struct user_regs_struct,fs): if (value && (value & 3) != 3) |