From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f177.google.com (mail-qc0-f177.google.com [209.85.216.177]) by kanga.kvack.org (Postfix) with ESMTP id 031726B0037 for ; Wed, 15 Jan 2014 13:02:21 -0500 (EST) Received: by mail-qc0-f177.google.com with SMTP id i8so1272396qcq.22 for ; Wed, 15 Jan 2014 10:02:21 -0800 (PST) Received: from mail-qa0-x234.google.com (mail-qa0-x234.google.com [2607:f8b0:400d:c00::234]) by mx.google.com with ESMTPS id x4si6351075qad.172.2014.01.15.10.02.19 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 15 Jan 2014 10:02:19 -0800 (PST) Received: by mail-qa0-f52.google.com with SMTP id j15so1187557qaq.39 for ; Wed, 15 Jan 2014 10:02:18 -0800 (PST) From: William Roberts Subject: [PATCH v3 1/3] mm: Create utility function for accessing a tasks commandline value Date: Wed, 15 Jan 2014 13:02:12 -0500 Message-Id: <1389808934-4446-1-git-send-email-wroberts@tresys.com> Sender: owner-linux-mm@kvack.org List-ID: 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 introduce get_cmdline() for retreiving the value of a processes proc/self/cmdline value. Acked-by: David Rientjes Acked-by: Stephen Smalley 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 3552717..01e7970 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1134,6 +1134,7 @@ 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 808f375..43b4419 100644 --- a/mm/util.c +++ b/mm/util.c @@ -413,6 +413,54 @@ unsigned long vm_commit_limit(void) * sysctl_overcommit_ratio / 100) + total_swap_pages; } +/** + * 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org