From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Mathieu Malaterre <malat@debian.org>
Subject: [PATCH v2] powerpc/signal32: Use fault_in_pages_readable() to prefault user context
Date: Tue, 24 Apr 2018 18:04:25 +0200 (CEST) [thread overview]
Message-ID: <20180424160425.DB9946C5A7@po15720vm.idsi0.si.c-s.fr> (raw)
Use fault_in_pages_readable() to prefault user context
instead of open coding
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
v2: using sizeof(*ctx) as size of ctx instead of 1
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 492f03451877..4a9e4d6d555b 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>
#ifdef CONFIG_PPC64
#include <linux/syscalls.h>
@@ -1045,7 +1046,6 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
struct ucontext __user *new_ctx,
int ctx_size, int r6, int r7, int r8, struct pt_regs *regs)
{
- unsigned char tmp __maybe_unused;
int ctx_has_vsx_region = 0;
#ifdef CONFIG_PPC64
@@ -1109,9 +1109,8 @@ long sys_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;
/*
@@ -1231,7 +1230,6 @@ int sys_debug_setcontext(struct ucontext __user *ctx,
{
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;
@@ -1287,9 +1285,8 @@ int sys_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;
/*
--
2.13.3
next reply other threads:[~2018-04-24 16:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-24 16:04 Christophe Leroy [this message]
2018-04-24 18:53 ` [PATCH v2] powerpc/signal32: Use fault_in_pages_readable() to prefault user context Mathieu Malaterre
2018-06-04 14:10 ` [v2] " Michael Ellerman
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