From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753286Ab1CFRL7 (ORCPT ); Sun, 6 Mar 2011 12:11:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4129 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750726Ab1CFRL4 (ORCPT ); Sun, 6 Mar 2011 12:11:56 -0500 Date: Sun, 6 Mar 2011 18:02:37 +0100 From: Oleg Nesterov To: Andrew Morton Cc: LKML , linux-mm , pageexec@freemail.hu, Solar Designer , Eugene Teo , Brad Spengler , Roland McGrath , Milton Miller , Linus Torvalds , KOSAKI Motohiro Subject: [PATCH v5 2/4] exec: introduce struct user_arg_ptr Message-ID: <20110306170237.GC24175@redhat.com> References: <20110305203040.GA7546@redhat.com> <20110306210334.6CD5.A69D9226@jp.fujitsu.com> <20110306170156.GA24175@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110306170156.GA24175@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org No functional changes, preparation. Introduce struct user_arg_ptr, change do_execve() paths to use it instead of "char __user * const __user *argv". This makes the argv/envp arguments opaque, we are ready to handle the compat case which needs argv pointing to compat_uptr_t. Suggested-by: Linus Torvalds Signed-off-by: Oleg Nesterov Reviewed-by: KOSAKI Motohiro Tested-by: KOSAKI Motohiro --- fs/exec.c | 42 ++++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 12 deletions(-) --- 38/fs/exec.c~2_typedef_for_argv 2011-03-06 17:51:01.000000000 +0100 +++ 38/fs/exec.c 2011-03-06 17:51:44.000000000 +0100 @@ -395,12 +395,15 @@ err: return err; } -static const char __user * -get_user_arg_ptr(const char __user * const __user *argv, int nr) +struct user_arg_ptr { + const char __user *const __user *native; +}; + +static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) { const char __user *ptr; - if (get_user(ptr, argv + nr)) + if (get_user(ptr, argv.native + nr)) return ERR_PTR(-EFAULT); return ptr; @@ -409,11 +412,11 @@ get_user_arg_ptr(const char __user * con /* * count() counts the number of strings in array ARGV. */ -static int count(const char __user * const __user * argv, int max) +static int count(struct user_arg_ptr argv, int max) { int i = 0; - if (argv != NULL) { + if (argv.native != NULL) { for (;;) { const char __user *p = get_user_arg_ptr(argv, i); @@ -439,7 +442,7 @@ static int count(const char __user * con * processes's memory to the new process's stack. The call to get_user_pages() * ensures the destination page is created and not swapped out. */ -static int copy_strings(int argc, const char __user *const __user *argv, +static int copy_strings(int argc, struct user_arg_ptr argv, struct linux_binprm *bprm) { struct page *kmapped_page = NULL; @@ -530,14 +533,19 @@ out: /* * Like copy_strings, but get argv and its values from kernel memory. */ -int copy_strings_kernel(int argc, const char *const *argv, +int copy_strings_kernel(int argc, const char *const *__argv, struct linux_binprm *bprm) { int r; mm_segment_t oldfs = get_fs(); + struct user_arg_ptr argv = { + .native = (const char __user *const __user *)__argv, + }; + set_fs(KERNEL_DS); - r = copy_strings(argc, (const char __user *const __user *)argv, bprm); + r = copy_strings(argc, argv, bprm); set_fs(oldfs); + return r; } EXPORT_SYMBOL(copy_strings_kernel); @@ -1387,10 +1395,10 @@ EXPORT_SYMBOL(search_binary_handler); /* * sys_execve() executes a new program. */ -int do_execve(const char * filename, - const char __user *const __user *argv, - const char __user *const __user *envp, - struct pt_regs * regs) +static int do_execve_common(const char *filename, + struct user_arg_ptr argv, + struct user_arg_ptr envp, + struct pt_regs *regs) { struct linux_binprm *bprm; struct file *file; @@ -1497,6 +1505,16 @@ out_ret: return retval; } +int do_execve(const char *filename, + const char __user *const __user *__argv, + const char __user *const __user *__envp, + struct pt_regs *regs) +{ + struct user_arg_ptr argv = { .native = __argv }; + struct user_arg_ptr envp = { .native = __envp }; + return do_execve_common(filename, argv, envp, regs); +} + void set_binfmt(struct linux_binfmt *new) { struct mm_struct *mm = current->mm;