Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932446AbVJYWGl (ORCPT ); Tue, 25 Oct 2005 18:06:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932432AbVJYWFl (ORCPT ); Tue, 25 Oct 2005 18:05:41 -0400 Received: from [151.97.230.9] ([151.97.230.9]:56805 "EHLO ssc.unict.it") by vger.kernel.org with ESMTP id S932428AbVJYWFc (ORCPT ); Tue, 25 Oct 2005 18:05:32 -0400 From: "Paolo 'Blaisorblade' Giarrusso" Subject: [PATCH 02/11] Uml: fix access_ok Date: Wed, 26 Oct 2005 00:01:10 +0200 To: Jeff Dike Cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net Message-Id: <20051025220107.20010.57705.stgit@zion.home.lan> In-Reply-To: <20051025220053.20010.56979.stgit@zion.home.lan> References: <20051025220053.20010.56979.stgit@zion.home.lan> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6887 Lines: 188 From: Paolo 'Blaisorblade' Giarrusso The access_ok_tt() macro is bogus, in that a read access is unconditionally considered valid. I couldn't find in SCM logs the introduction of this check, but I went back to 2.4.20-1um and the definition was the same. Possibly this was done to avoid problems with missing set_fs() calls, but there can't be any I think because they would fail with SKAS mode. TT-specific code is still to check. Also, this patch joins common code together, and makes the "address range wrapping" check happen for all cases, rather than for only some. This may, possibly, be reoptimized at some time, but the current code doesn't seem clever, just confused. * Important: I've also had to change references to access_ok_{tt,skas} back to access_ok - the kernel wasn't that happy otherwise. Signed-off-by: Paolo 'Blaisorblade' Giarrusso --- arch/um/include/um_uaccess.h | 19 ++++++++++++++++++- arch/um/kernel/skas/include/uaccess-skas.h | 10 ++-------- arch/um/kernel/skas/uaccess.c | 8 ++++---- arch/um/kernel/tt/include/uaccess-tt.h | 8 +------- arch/um/kernel/tt/uaccess.c | 8 ++++---- 5 files changed, 29 insertions(+), 24 deletions(-) diff --git a/arch/um/include/um_uaccess.h b/arch/um/include/um_uaccess.h --- a/arch/um/include/um_uaccess.h +++ b/arch/um/include/um_uaccess.h @@ -17,8 +17,25 @@ #include "uaccess-skas.h" #endif +#define __under_task_size(addr, size) \ + (((unsigned long) (addr) < TASK_SIZE) && \ + (((unsigned long) (addr) + (size)) < TASK_SIZE)) + +#define __access_ok_vsyscall(type, addr, size) \ + ((type == VERIFY_READ) && \ + ((unsigned long) (addr) >= FIXADDR_USER_START) && \ + ((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \ + ((unsigned long) (addr) + (size) >= (unsigned long)(addr))) + +#define __addr_range_nowrap(addr, size) \ + ((unsigned long) (addr) <= ((unsigned long) (addr) + (size))) + #define access_ok(type, addr, size) \ - CHOOSE_MODE_PROC(access_ok_tt, access_ok_skas, type, addr, size) + (__addr_range_nowrap(addr, size) && \ + (__under_task_size(addr, size) || \ + __access_ok_vsyscall(type, addr, size) || \ + segment_eq(get_fs(), KERNEL_DS) || \ + CHOOSE_MODE_PROC(access_ok_tt, access_ok_skas, type, addr, size))) static inline int copy_from_user(void *to, const void __user *from, int n) { diff --git a/arch/um/kernel/skas/include/uaccess-skas.h b/arch/um/kernel/skas/include/uaccess-skas.h --- a/arch/um/kernel/skas/include/uaccess-skas.h +++ b/arch/um/kernel/skas/include/uaccess-skas.h @@ -9,14 +9,8 @@ #include "asm/errno.h" #include "asm/fixmap.h" -#define access_ok_skas(type, addr, size) \ - ((segment_eq(get_fs(), KERNEL_DS)) || \ - (((unsigned long) (addr) < TASK_SIZE) && \ - ((unsigned long) (addr) + (size) <= TASK_SIZE)) || \ - ((type == VERIFY_READ ) && \ - ((unsigned long) (addr) >= FIXADDR_USER_START) && \ - ((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \ - ((unsigned long) (addr) + (size) >= (unsigned long)(addr)))) +/* No SKAS-specific checking. */ +#define access_ok_skas(type, addr, size) 0 extern int copy_from_user_skas(void *to, const void __user *from, int n); extern int copy_to_user_skas(void __user *to, const void *from, int n); diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c --- a/arch/um/kernel/skas/uaccess.c +++ b/arch/um/kernel/skas/uaccess.c @@ -143,7 +143,7 @@ int copy_from_user_skas(void *to, const return(0); } - return(access_ok_skas(VERIFY_READ, from, n) ? + return(access_ok(VERIFY_READ, from, n) ? buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to): n); } @@ -164,7 +164,7 @@ int copy_to_user_skas(void __user *to, c return(0); } - return(access_ok_skas(VERIFY_WRITE, to, n) ? + return(access_ok(VERIFY_WRITE, to, n) ? buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) : n); } @@ -193,7 +193,7 @@ int strncpy_from_user_skas(char *dst, co return(strnlen(dst, count)); } - if(!access_ok_skas(VERIFY_READ, src, 1)) + if(!access_ok(VERIFY_READ, src, 1)) return(-EFAULT); n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user, @@ -221,7 +221,7 @@ int clear_user_skas(void __user *mem, in return(0); } - return(access_ok_skas(VERIFY_WRITE, mem, len) ? + return(access_ok(VERIFY_WRITE, mem, len) ? buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len); } diff --git a/arch/um/kernel/tt/include/uaccess-tt.h b/arch/um/kernel/tt/include/uaccess-tt.h --- a/arch/um/kernel/tt/include/uaccess-tt.h +++ b/arch/um/kernel/tt/include/uaccess-tt.h @@ -19,19 +19,13 @@ extern unsigned long end_vm; extern unsigned long uml_physmem; -#define under_task_size(addr, size) \ - (((unsigned long) (addr) < TASK_SIZE) && \ - (((unsigned long) (addr) + (size)) < TASK_SIZE)) - #define is_stack(addr, size) \ (((unsigned long) (addr) < STACK_TOP) && \ ((unsigned long) (addr) >= STACK_TOP - ABOVE_KMEM) && \ (((unsigned long) (addr) + (size)) <= STACK_TOP)) #define access_ok_tt(type, addr, size) \ - ((type == VERIFY_READ) || (segment_eq(get_fs(), KERNEL_DS)) || \ - (((unsigned long) (addr) <= ((unsigned long) (addr) + (size))) && \ - (under_task_size(addr, size) || is_stack(addr, size)))) + (is_stack(addr, size)) extern unsigned long get_fault_addr(void); diff --git a/arch/um/kernel/tt/uaccess.c b/arch/um/kernel/tt/uaccess.c --- a/arch/um/kernel/tt/uaccess.c +++ b/arch/um/kernel/tt/uaccess.c @@ -8,7 +8,7 @@ int copy_from_user_tt(void *to, const void __user *from, int n) { - if(!access_ok_tt(VERIFY_READ, from, n)) + if(!access_ok(VERIFY_READ, from, n)) return(n); return(__do_copy_from_user(to, from, n, ¤t->thread.fault_addr, @@ -17,7 +17,7 @@ int copy_from_user_tt(void *to, const vo int copy_to_user_tt(void __user *to, const void *from, int n) { - if(!access_ok_tt(VERIFY_WRITE, to, n)) + if(!access_ok(VERIFY_WRITE, to, n)) return(n); return(__do_copy_to_user(to, from, n, ¤t->thread.fault_addr, @@ -28,7 +28,7 @@ int strncpy_from_user_tt(char *dst, cons { int n; - if(!access_ok_tt(VERIFY_READ, src, 1)) + if(!access_ok(VERIFY_READ, src, 1)) return(-EFAULT); n = __do_strncpy_from_user(dst, src, count, @@ -47,7 +47,7 @@ int __clear_user_tt(void __user *mem, in int clear_user_tt(void __user *mem, int len) { - if(!access_ok_tt(VERIFY_WRITE, mem, len)) + if(!access_ok(VERIFY_WRITE, mem, len)) return(len); return(__do_clear_user(mem, len, ¤t->thread.fault_addr, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/