From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f50.google.com (mail-yh0-f50.google.com [209.85.213.50]) by kanga.kvack.org (Postfix) with ESMTP id 4A7106B0031 for ; Wed, 15 Jan 2014 09:16:22 -0500 (EST) Received: by mail-yh0-f50.google.com with SMTP id f10so554901yha.37 for ; Wed, 15 Jan 2014 06:16:21 -0800 (PST) Received: from nsa.gov (emvm-gh1-uea09.nsa.gov. [63.239.67.10]) by mx.google.com with ESMTP id t28si1513914yhd.286.2014.01.15.06.16.19 for ; Wed, 15 Jan 2014 06:16:20 -0800 (PST) Message-ID: <52D6980D.1010206@tycho.nsa.gov> Date: Wed, 15 Jan 2014 09:15:41 -0500 From: Stephen Smalley MIME-Version: 1.0 Subject: Re: [RFC][PATCH v2 1/3] mm: Create utility function for accessing a tasks commandline value References: <1389632555-7039-1-git-send-email-wroberts@tresys.com> In-Reply-To: <1389632555-7039-1-git-send-email-wroberts@tresys.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: William Roberts , 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 Cc: William Roberts On 01/13/2014 12:02 PM, William Roberts wrote: > introduce get_cmdline() for retreiving the value of a processes > proc/self/cmdline value. > > Signed-off-by: William Roberts Acked-by: Stephen Smalley > --- > 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 f7bc209..5285ff0 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -410,6 +410,54 @@ 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); > -- 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