Re: [PATCH] powerpc/ptrace: Use copy_{from, to}_user() rather than open-coding
From: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Date: 2018-05-30 06:48:56
On Tue, 2018-05-29 at 22:57 +1000, Michael Ellerman wrote:
From: Al Viro <viro@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 <viro@zeniv.linux.org.uk>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
quoted hunk ↗ jump to hunk
--- 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: {