LU-4563 Fix unsafe userspace access in many proc files

[fs/lustre-release.git] / lustre / obdclass / linux / linux-module.c

diff --git a/lustre/obdclass/linux/linux-module.c b/lustre/obdclass/linux/linux-module.c
index e96802d..1642123 100644 (file)
--- a/lustre/obdclass/linux/linux-module.c
+++ b/lustre/obdclass/linux/linux-module.c
@@ -300,15 +300,22 @@ static int obd_proc_jobid_var_seq_show(struct seq_file *m, void *v)
 }
 
 static ssize_t
-obd_proc_jobid_var_seq_write(struct file *file, const char *buffer,
-                               size_t count, loff_t *off)
+obd_proc_jobid_var_seq_write(struct file *file, const char __user *buffer,
+                            size_t count, loff_t *off)
 {
        if (!count || count > JOBSTATS_JOBID_VAR_MAX_LEN)
                return -EINVAL;
 
        memset(obd_jobid_var, 0, JOBSTATS_JOBID_VAR_MAX_LEN + 1);
+
+       /* This might leave the var invalid on error, which is probably fine.*/
+       if (copy_from_user(obd_jobid_var, buffer, count))
+               return -EFAULT;
+
        /* Trim the trailing '\n' if any */
-       memcpy(obd_jobid_var, buffer, count - (buffer[count - 1] == '\n'));
+       if (obd_jobid_var[count - 1] == '\n')
+               obd_jobid_var[count - 1] = 0;
+
        return count;
 }
 LPROC_SEQ_FOPS(obd_proc_jobid_var);