[PATCH] powerpc/signal32: Use fault_in_pages_readable() to prefault user context
From: Christophe Leroy <hidden>
Date: 2018-04-24 14:18:04
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Use fault_in_pages_readable() to prefault user context instead of open coding Signed-off-by: Christophe Leroy <redacted> --- 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..cfacb2726152 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, 1)) return -EFAULT; /*
--
2.13.3