On Tue, 2018-05-29 at 22:57 +1000, Michael Ellerman wrote:
> From: Al Viro <v...@zeniv.linux.org.uk>
>
> In PPC_PTRACE_GETHWDBGINFO and PPC_PTRACE_SETHWDEBUG we do an
> access_ok() check and then __copy_{from,to}_user().
>
> Instead we should just use copy_{from,to}_user() which does all that
> for us and is less error prone.
>
> Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
> Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Reviewed-by: Samuel Mendoza-Jonas <s...@mendozajonas.com>
> ---
> arch/powerpc/kernel/ptrace.c | 20 ++++++--------------
> 1 file changed, 6 insertions(+), 14 deletions(-)
>
> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index 0f63dd5972e9..9667666eb18e 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -3082,27 +3082,19 @@ long arch_ptrace(struct task_struct *child, long
> request,
> #endif /* CONFIG_HAVE_HW_BREAKPOINT */
> #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
>
> - if (!access_ok(VERIFY_WRITE, datavp,
> - sizeof(struct ppc_debug_info)))
> + if (copy_to_user(datavp, &dbginfo,
> + sizeof(struct ppc_debug_info)))
> return -EFAULT;
> - ret = __copy_to_user(datavp, &dbginfo,
> - sizeof(struct ppc_debug_info)) ?
> - -EFAULT : 0;
> - break;
> + return 0;
> }
>
> case PPC_PTRACE_SETHWDEBUG: {
> struct ppc_hw_breakpoint bp_info;
>
> - if (!access_ok(VERIFY_READ, datavp,
> - sizeof(struct ppc_hw_breakpoint)))
> + if (copy_from_user(&bp_info, datavp,
> + sizeof(struct ppc_hw_breakpoint)))
> return -EFAULT;
> - ret = __copy_from_user(&bp_info, datavp,
> - sizeof(struct ppc_hw_breakpoint)) ?
> - -EFAULT : 0;
> - if (!ret)
> - ret = ppc_set_hwdebug(child, &bp_info);
> - break;
> + return ppc_set_hwdebug(child, &bp_info);
> }
>
> case PPC_PTRACE_DELHWDEBUG: {
