From 56b04d568f880a48d892e840cfaf4efc0f0ce39b Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@c-s.fr>
Date: Tue, 24 Apr 2018 18:04:25 +0200
Subject: [PATCH] powerpc/signal32: Use fault_in_pages_readable() to prefault
user context
Use fault_in_pages_readable() to prefault user context
instead of open coding
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/kernel/signal_32.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 342ac78f620f5..5eedbb282d42f 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -25,6 +25,7 @@
#include <linux/errno.h>
#include <linux/elf.h>
#include <linux/ptrace.h>
+#include <linux/pagemap.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
#ifdef CONFIG_PPC64
@@ -1049,7 +1050,6 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
#endif
{
struct pt_regs *regs = current_pt_regs();
- unsigned char tmp __maybe_unused;
int ctx_has_vsx_region = 0;
#ifdef CONFIG_PPC64
@@ -1113,9 +1113,8 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
}
if (new_ctx == NULL)
return 0;
- if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
- || __get_user(tmp, (u8 __user *) new_ctx)
- || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
+ if (!access_ok(VERIFY_READ, new_ctx, ctx_size) ||
+ fault_in_pages_readable((u8 __user *)new_ctx, ctx_size))
return -EFAULT;
/*
@@ -1242,7 +1241,6 @@ SYSCALL_DEFINE3(debug_setcontext, struct ucontext __user *, ctx,
struct pt_regs *regs = current_pt_regs();
struct sig_dbg_op op;
int i;
- unsigned char tmp __maybe_unused;
unsigned long new_msr = regs->msr;
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
unsigned long new_dbcr0 = current->thread.debug.dbcr0;
@@ -1298,9 +1296,8 @@ SYSCALL_DEFINE3(debug_setcontext, struct ucontext __user *, ctx,
current->thread.debug.dbcr0 = new_dbcr0;
#endif
- if (!access_ok(VERIFY_READ, ctx, sizeof(*ctx))
- || __get_user(tmp, (u8 __user *) ctx)
- || __get_user(tmp, (u8 __user *) (ctx + 1) - 1))
+ if (!access_ok(VERIFY_READ, ctx, sizeof(*ctx)) ||
+ fault_in_pages_readable((u8 __user *)ctx, sizeof(*ctx)))
return -EFAULT;
/*
--
2.30.2