From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40Vp723KZGzF1RV for ; Wed, 25 Apr 2018 02:04:30 +1000 (AEST) From: Christophe Leroy Subject: [PATCH v2] powerpc/signal32: Use fault_in_pages_readable() to prefault user context To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Mathieu Malaterre Message-Id: <20180424160425.DB9946C5A7@po15720vm.idsi0.si.c-s.fr> Date: Tue, 24 Apr 2018 18:04:25 +0200 (CEST) List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Use fault_in_pages_readable() to prefault user context instead of open coding Signed-off-by: Christophe Leroy --- 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 #include #include +#include #include #ifdef CONFIG_PPC64 #include @@ -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