From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935016AbdKGBEK (ORCPT ); Mon, 6 Nov 2017 20:04:10 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52580 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755258AbdKFXyJ (ORCPT ); Mon, 6 Nov 2017 18:54:09 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Arnd Bergmann" , "Kalle Valo" Date: Mon, 06 Nov 2017 23:03:02 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 254/294] hostap: avoid uninitialized variable use in hfa384x_get_rid In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit 48dc5fb3ba53b20418de8514700f63d88c5de3a3 upstream. The driver reads a value from hfa384x_from_bap(), which may fail, and then assigns the value to a local variable. gcc detects that in in the failure case, the 'rlen' variable now contains uninitialized data: In file included from ../drivers/net/wireless/intersil/hostap/hostap_pci.c:220:0: drivers/net/wireless/intersil/hostap/hostap_hw.c: In function 'hfa384x_get_rid': drivers/net/wireless/intersil/hostap/hostap_hw.c:842:5: warning: 'rec' may be used uninitialized in this function [-Wmaybe-uninitialized] if (le16_to_cpu(rec.len) == 0) { This restructures the function as suggested by Russell King, to make it more readable and get more reliable error handling, by handling each failure mode using a goto. Signed-off-by: Arnd Bergmann Signed-off-by: Kalle Valo Signed-off-by: Ben Hutchings --- drivers/net/wireless/hostap/hostap_hw.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/drivers/net/wireless/hostap/hostap_hw.c +++ b/drivers/net/wireless/hostap/hostap_hw.c @@ -836,25 +836,30 @@ static int hfa384x_get_rid(struct net_de spin_lock_bh(&local->baplock); res = hfa384x_setup_bap(dev, BAP0, rid, 0); - if (!res) - res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec)); + if (res) + goto unlock; + + res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec)); + if (res) + goto unlock; if (le16_to_cpu(rec.len) == 0) { /* RID not available */ res = -ENODATA; + goto unlock; } rlen = (le16_to_cpu(rec.len) - 1) * 2; - if (!res && exact_len && rlen != len) { + if (exact_len && rlen != len) { printk(KERN_DEBUG "%s: hfa384x_get_rid - RID len mismatch: " "rid=0x%04x, len=%d (expected %d)\n", dev->name, rid, rlen, len); res = -ENODATA; } - if (!res) - res = hfa384x_from_bap(dev, BAP0, buf, len); + res = hfa384x_from_bap(dev, BAP0, buf, len); +unlock: spin_unlock_bh(&local->baplock); mutex_unlock(&local->rid_bap_mtx);