[PATCH 4.16 006/272] MIPS: Fix ptrace(2) PTRACE_PEEKUSR and PTRACE_POKEUSR accesses to o32 FGRs

Greg Kroah-Hartman
2018-05-28T11:04:38Z

From: Maciej W. Rozycki <macro@mips.com>

commit 9a3a92ccfe3620743d4ae57c987dc8e9c5f88996 upstream.

Check the TIF_32BIT_FPREGS task setting of the tracee rather than the
tracer in determining the layout of floating-point general registers in
the floating-point context, correcting access to odd-numbered registers
for o32 tracees where the setting disagrees between the two processes.

Fixes: 597ce1723e0f ("MIPS: Support for 64-bit FP with O32 binaries")
Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.14+
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/kernel/ptrace.c | 4 ++--
arch/mips/kernel/ptrace32.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -807,7 +807,7 @@ long arch_ptrace(struct task_struct *chi
fregs = get_fpu_regs(child);

#ifdef CONFIG_32BIT
- if (test_thread_flag(TIF_32BIT_FPREGS)) {
+ if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) {
/*
* The odd registers are actually the high
* order bits of the values stored in the even
@@ -902,7 +902,7 @@ long arch_ptrace(struct task_struct *chi

init_fp_ctx(child);
#ifdef CONFIG_32BIT
- if (test_thread_flag(TIF_32BIT_FPREGS)) {
+ if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) {
/*
* The odd registers are actually the high
* order bits of the values stored in the even
--- a/arch/mips/kernel/ptrace32.c
+++ b/arch/mips/kernel/ptrace32.c
@@ -99,7 +99,7 @@ long compat_arch_ptrace(struct task_stru
break;
}
fregs = get_fpu_regs(child);
- if (test_thread_flag(TIF_32BIT_FPREGS)) {
+ if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) {
/*
* The odd registers are actually the high
* order bits of the values stored in the even
@@ -212,7 +212,7 @@ long compat_arch_ptrace(struct task_stru
sizeof(child->thread.fpu));
child->thread.fpu.fcr31 = 0;
}
- if (test_thread_flag(TIF_32BIT_FPREGS)) {
+ if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) {
/*
* The odd registers are actually the high
* order bits of the values stored in the even