"len" hasn't been properly range checked so we shouldn't use it as an array offset. This can only be written to by root but it would still be annoying to accidentally write more than 3 characters and corrupt your memory. Signed-off-by: Dan Carpenter <error27@xxxxxxxxx> --- I don't have a cross compile environment to compile this. Sorry. :/ diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c index f449c69..72c2e90 100644 --- a/drivers/s390/char/sclp_async.c +++ b/drivers/s390/char/sclp_async.c @@ -84,7 +84,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write, rc = copy_from_user(buf, buffer, sizeof(buf)); if (rc != 0) return -EFAULT; - buf[len - 1] = '\0'; + buf[sizeof(buf) - 1] = '\0'; if (strict_strtoul(buf, 0, &val) != 0) return -EINVAL; if (val != 0 && val != 1) @@ -99,6 +99,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write, static struct ctl_table callhome_table[] = { { .procname = "callhome", + .maxlen = 3, .mode = 0644, .proc_handler = proc_handler_callhome, }, -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html