Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756607Ab0K3UDl (ORCPT ); Tue, 30 Nov 2010 15:03:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38207 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756567Ab0K3UDj (ORCPT ); Tue, 30 Nov 2010 15:03:39 -0500 Date: Tue, 30 Nov 2010 20:56:02 +0100 From: Oleg Nesterov To: KOSAKI Motohiro , Andrew Morton , Linus Torvalds Cc: LKML , linux-mm , pageexec@freemail.hu, Solar Designer , Eugene Teo , Brad Spengler , Roland McGrath , stable@kernel.org Subject: [PATCH 2/2] exec: copy-and-paste the fixes into compat_do_execve() paths Message-ID: <20101130195602.GC11905@redhat.com> References: <20101125140253.GA29371@redhat.com> <20101125193659.GA14510@redhat.com> <20101129093803.829F.A69D9226@jp.fujitsu.com> <20101129113357.GA30657@redhat.com> <20101129182332.GA21470@redhat.com> <20101130195456.GA11905@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101130195456.GA11905@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 Content-Length: 4243 Lines: 136 Note: this patch targets 2.6.37 and tries to be as simple as possible. That is why it adds more copy-and-paste horror into fs/compat.c and uglifies fs/exec.c, this will be cleanuped later. compat_copy_strings() plays with bprm->vma/mm directly and thus has two problems: it lacks the RLIMIT_STACK check and argv/envp memory is not visible to oom killer. Export acct_arg_size() and get_arg_page(), change compat_copy_strings() to use get_arg_page(), change compat_do_execve() to do acct_arg_size(0) as do_execve() does. Add the fatal_signal_pending/cond_resched checks into compat_count() and compat_copy_strings(), this matches the code in fs/exec.c and certainly makes sense. Signed-off-by: Oleg Nesterov --- include/linux/binfmts.h | 4 ++++ fs/exec.c | 8 ++++---- fs/compat.c | 28 +++++++++++++++------------- 3 files changed, 23 insertions(+), 17 deletions(-) --- K/include/linux/binfmts.h~compat_get_arg_page 2010-11-30 18:28:54.000000000 +0100 +++ K/include/linux/binfmts.h 2010-11-30 18:30:45.000000000 +0100 @@ -60,6 +60,10 @@ struct linux_binprm{ unsigned long loader, exec; }; +extern void acct_arg_size(struct linux_binprm *bprm, unsigned long pages); +extern struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, + int write); + #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0 #define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT) --- K/fs/exec.c~compat_get_arg_page 2010-11-30 18:28:54.000000000 +0100 +++ K/fs/exec.c 2010-11-30 18:30:45.000000000 +0100 @@ -164,7 +164,7 @@ out: #ifdef CONFIG_MMU -static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) +void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) { struct mm_struct *mm = current->mm; long diff = (long)(pages - bprm->vma_pages); @@ -183,7 +183,7 @@ static void acct_arg_size(struct linux_b #endif } -static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, +struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, int write) { struct page *page; @@ -297,11 +297,11 @@ static bool valid_arg_len(struct linux_b #else -static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) +void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) { } -static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, +struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, int write) { struct page *page; --- K/fs/compat.c~compat_get_arg_page 2010-11-30 17:55:20.000000000 +0100 +++ K/fs/compat.c 2010-11-30 18:30:45.000000000 +0100 @@ -1350,6 +1350,10 @@ static int compat_count(compat_uptr_t __ argv++; if (i++ >= max) return -E2BIG; + + if (fatal_signal_pending(current)) + return -ERESTARTNOHAND; + cond_resched(); } } return i; @@ -1391,6 +1395,12 @@ static int compat_copy_strings(int argc, while (len > 0) { int offset, bytes_to_copy; + if (fatal_signal_pending(current)) { + ret = -ERESTARTNOHAND; + goto out; + } + cond_resched(); + offset = pos % PAGE_SIZE; if (offset == 0) offset = PAGE_SIZE; @@ -1407,18 +1417,8 @@ static int compat_copy_strings(int argc, if (!kmapped_page || kpos != (pos & PAGE_MASK)) { struct page *page; -#ifdef CONFIG_STACK_GROWSUP - ret = expand_stack_downwards(bprm->vma, pos); - if (ret < 0) { - /* We've exceed the stack rlimit. */ - ret = -E2BIG; - goto out; - } -#endif - ret = get_user_pages(current, bprm->mm, pos, - 1, 1, 1, &page, NULL); - if (ret <= 0) { - /* We've exceed the stack rlimit. */ + page = get_arg_page(bprm, pos, 1); + if (!page) { ret = -E2BIG; goto out; } @@ -1539,8 +1539,10 @@ int compat_do_execve(char * filename, return retval; out: - if (bprm->mm) + if (bprm->mm) { + acct_arg_size(bprm, 0); mmput(bprm->mm); + } out_file: if (bprm->file) { -- 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/