arm64/ptrace: Preserve previous registers for short regset write - 3

commit a672401c00f82e4e19704aff361d9bad18003714 upstream.

Ensure that if userspace supplies insufficient data to
PTRACE_SETREGSET to fill all the registers, the thread's old
registers are preserved.

Fixes: 5d220ff9420f ("arm64: Better native ptrace support for compat tasks")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Will Deacon <Will.Deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dave Martin 2017-01-18 16:25:22 +00:00 committed by Greg Kroah-Hartman
parent d8263f1753
commit 03ee97d68d

View File

@ -849,7 +849,7 @@ static int compat_tls_set(struct task_struct *target,
const void __user *ubuf)
{
int ret;
compat_ulong_t tls;
compat_ulong_t tls = target->thread.tp_value;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
if (ret)