Re: [PATCH v5 2/3] proc: Update get proc_pid_cmdline() to use mm.h helpers

From: Richard Guy Briggs
Date: Tue Feb 11 2014 - 12:59:16 EST


On 14/02/06, William Roberts wrote:
> Re-factor proc_pid_cmdline() to use get_cmdline() helper
> from mm.h.
>
> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
> Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>

Acked-by: Richard Guy Briggs <rgb@xxxxxxxxxx>

> Signed-off-by: William Roberts <wroberts@xxxxxxxxxx>
> ---
> fs/proc/base.c | 36 ++----------------------------------
> 1 file changed, 2 insertions(+), 34 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 5150706..f0c5927 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -200,41 +200,9 @@ static int proc_root_link(struct dentry *dentry, struct path *path)
> return result;
> }
>
> -static int proc_pid_cmdline(struct task_struct *task, char * buffer)
> +static int proc_pid_cmdline(struct task_struct *task, char *buffer)
> {
> - 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 > PAGE_SIZE)
> - len = PAGE_SIZE;
> -
> - 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 < PAGE_SIZE) {
> - len = strnlen(buffer, res);
> - if (len < res) {
> - res = len;
> - } else {
> - len = mm->env_end - mm->env_start;
> - if (len > PAGE_SIZE - res)
> - len = PAGE_SIZE - res;
> - res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
> - res = strnlen(buffer, res);
> - }
> - }
> -out_mm:
> - mmput(mm);
> -out:
> - return res;
> + return get_cmdline(task, buffer, PAGE_SIZE);
> }
>
> static int proc_pid_auxv(struct task_struct *task, char *buffer)
> --
> 1.7.9.5
>

- RGB

--
Richard Guy Briggs <rbriggs@xxxxxxxxxx>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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