linux-kernel - [PATCH 8/8] PCI: Don't scan random busses in pci_scan

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1390510768-5652-9-git-send-email-andreas.noever@gmail.com>
Date:	Thu, 23 Jan 2014 21:59:28 +0100
From:	Andreas Noever <andreas.noever@...il.com>
To:	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	bhelgaas@...gle.com
Cc:	Andreas Noever <andreas.noever@...il.com>
Subject: [PATCH 8/8] PCI: Don't scan random busses in pci_scan_bridge.

When assigning a new bus number in pci_scan_bridge we check whether
max+1 is free by calling pci_find_bus. If it does already exists then we
assume that we are rescanning and that this is the right bus to scan.

This is fragile. If max+1 lies outside of bus->busn_res.end then we will
rescan some random bus from somewhere else in the hierachy. This patch
checks for this case and prints a warning.

Signed-off-by: Andreas Noever <andreas.noever@...il.com>
---
 drivers/pci/probe.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 74bc644..0a94de2 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -830,12 +830,16 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
 			goto out;
 		}
 
+		if (max >= bus->busn_res.end) {
+			dev_warn(&dev->dev,
+				"parent bus ran out of bus numbers, cannot allocate child bus\n");
+			goto out;
+		}
+
 		/* Clear errors */
 		pci_write_config_word(dev, PCI_STATUS, 0xffff);
 
-		/* Prevent assigning a bus number that already exists.
-		 * This can happen when a bridge is hot-plugged, so in
-		 * this case we only re-scan this bus. */
+		/* The bus will already exist if we are rescanning */
 		child = pci_find_bus(pci_domain_nr(bus), max+1);
 		if (!child) {
 			child = pci_add_new_bus(bus, dev, max+1);
-- 
1.8.5.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/