Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753762AbaA1GDV (ORCPT ); Tue, 28 Jan 2014 01:03:21 -0500 Received: from mail-qc0-f178.google.com ([209.85.216.178]:54144 "EHLO mail-qc0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750931AbaA1GDU (ORCPT ); Tue, 28 Jan 2014 01:03:20 -0500 From: William Roberts To: linux-audit@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rgb@redhat.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, sds@tycho.nsa.gov Cc: William Roberts Subject: [PATCH v4 1/3] mm: Create utility function for accessing a tasks commandline value Date: Mon, 27 Jan 2014 22:03:21 -0800 Message-Id: <1390889003-5058-1-git-send-email-wroberts@tresys.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org introduce get_cmdline() for retreiving the value of a processes proc/self/cmdline value. Signed-off-by: William Roberts --- include/linux/mm.h | 1 + mm/util.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index f28f46e..db89a94 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1175,6 +1175,7 @@ void account_page_writeback(struct page *page); int set_page_dirty(struct page *page); int set_page_dirty_lock(struct page *page); int clear_page_dirty_for_io(struct page *page); +int get_cmdline(struct task_struct *task, char *buffer, int buflen); /* Is the vma a continuation of the stack vma above it? */ static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr) diff --git a/mm/util.c b/mm/util.c index a24aa22..8122710 100644 --- a/mm/util.c +++ b/mm/util.c @@ -445,6 +445,54 @@ unsigned long vm_commit_limit(void) return allowed; } +/** + * get_cmdline() - copy the cmdline value to a buffer. + * @task: the task whose cmdline value to copy. + * @buffer: the buffer to copy to. + * @buflen: the length of the buffer. Larger cmdline values are truncated + * to this length. + * Returns the size of the cmdline field copied. Note that the copy does + * not guarantee an ending NULL byte. + */ +int get_cmdline(struct task_struct *task, char *buffer, int buflen) +{ + int res = 0; + unsigned int len; + struct mm_struct *mm = get_task_mm(task); + if (!mm) + goto out; + if (!mm->arg_end) + goto out_mm; /* Shh! No looking before we're done */ + + len = mm->arg_end - mm->arg_start; + + if (len > buflen) + len = buflen; + + res = access_process_vm(task, mm->arg_start, buffer, len, 0); + + /* + * If the nul at the end of args has been overwritten, then + * assume application is using setproctitle(3). + */ + if (res > 0 && buffer[res-1] != '\0' && len < buflen) { + len = strnlen(buffer, res); + if (len < res) { + res = len; + } else { + len = mm->env_end - mm->env_start; + if (len > buflen - res) + len = buflen - res; + res += access_process_vm(task, mm->env_start, + buffer+res, len, 0); + res = strnlen(buffer, res); + } + } +out_mm: + mmput(mm); +out: + return res; +} /* Tracepoints definitions. */ EXPORT_TRACEPOINT_SYMBOL(kmalloc); -- 1.7.9.5 -- 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/