oom: fix oom_adjust_write() input sanity check

Andrew Morton pointed out oom_adjust_write() has very strange EIO
and new line handling. this patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 71a3425..55c4c80 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1021,21 +1021,24 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
                                size_t count, loff_t *ppos)
 {
        struct task_struct *task;
-       char buffer[PROC_NUMBUF], *end;
-       int oom_adjust;
+       char buffer[PROC_NUMBUF];
+       long oom_adjust;
        unsigned long flags;
+       int err;
 
        memset(buffer, 0, sizeof(buffer));
        if (count > sizeof(buffer) - 1)
                count = sizeof(buffer) - 1;
        if (copy_from_user(buffer, buf, count))
                return -EFAULT;
-       oom_adjust = simple_strtol(buffer, &end, 0);
+
+       err = strict_strtol(strstrip(buffer), 0, &oom_adjust);
+       if (err)
+               return -EINVAL;
        if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
             oom_adjust != OOM_DISABLE)
                return -EINVAL;
-       if (*end == '\n')
-               end++;
+
        task = get_proc_task(file->f_path.dentry->d_inode);
        if (!task)
                return -ESRCH;
@@ -1054,9 +1057,8 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 
        unlock_task_sighand(task, &flags);
        put_task_struct(task);
-       if (end - buffer == 0)
-               return -EIO;
-       return end - buffer;
+
+       return count;
 }
 
 static const struct file_operations proc_oom_adjust_operations = {