From 56b04d568f880a48d892e840cfaf4efc0f0ce39b Mon Sep 17 00:00:00 2001 From: Christophe Leroy 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 Reviewed-by: Mathieu Malaterre Signed-off-by: Michael Ellerman --- 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 342ac78f620f..5eedbb282d42 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #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; /*