[PATCH 3.18 002/185] MIPS: Fix ptrace(2) PTRACE_PEEKUSR and PTRACE_POKEUSR accesses to o32 FGRs

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 12:50:07 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Maciej W. Rozycki <macro@xxxxxxxx>

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@xxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 3.14+
Signed-off-by: James Hogan <jhogan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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
@@ -702,7 +702,7 @@ 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
@@ -796,7 +796,7 @@ long arch_ptrace(struct task_struct *chi
child->thread.fpu.fcr31 = 0;
}
#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
@@ -97,7 +97,7 @@ 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
@@ -203,7 +203,7 @@ 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