linux-kernel - [PATCH] ACPI/PCI: Fix bus range comparation in pci_mcfg

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 for Android: free password hash cracker in your pocket

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

Date:   Wed, 4 Jan 2017 15:00:06 +0800
From:   Zhou Wang <wangzhou1@...ilicon.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Tomasz Nowicki <tn@...ihalf.com>,
        Jayachandran C <jchandra@...adcom.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        jorn Helgaas <bhelgaas@...gle.com>
CC:     <liudongdong3@...wei.com>, <gabriele.paoloni@...wei.com>,
        <xuwei5@...ilicon.com>, <linux-acpi@...r.kernel.org>,
        <linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Zhou Wang <wangzhou1@...ilicon.com>
Subject: [PATCH] ACPI/PCI: Fix bus range comparation in pci_mcfg_lookup

The configuration data provided by an MCFG region (ie PCI segment and
bus range) may span multiple host bridges.

Current code in pci_mcfg_lookup() carries out an exact match of host
bridge bus range start value against the MCFG region(s) bus range start
value which would cause configurations like the following:

MCFG region:
	bus range: 0x00~0xff.
	segment: 0.

PCI host bridges configuration (segment numbers and bus ranges):
	host bridge 1:
		bus range: 0x00~0x1f.
		segment: 0.
	host bridge 2:
		bus range: 0x20~0x4f.
		segment: 0.

to fail, in that the bus range start value for host bridge 2 does
not match the bus range start value of the respective MCFG region.

Relax the bus range check in pci_mcfg_lookup() to cater for
PCI configurations with multiple host bridges sharing the same
MCFG region.

Signed-off-by: Zhou Wang <wangzhou1@...ilicon.com>
Reviewed-by: Tomasz Nowicki <tn@...ihalf.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
---
 drivers/acpi/pci_mcfg.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index a6a4cea..2944353 100644
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -195,11 +195,10 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
 		goto skip_lookup;
 
 	/*
-	 * We expect exact match, unless MCFG entry end bus covers more than
-	 * specified by caller.
+	 * We expect the range in bus_res in the coverage of MCFG bus range.
 	 */
 	list_for_each_entry(e, &pci_mcfg_list, list) {
-		if (e->segment == seg && e->bus_start == bus_res->start &&
+		if (e->segment == seg && e->bus_start <= bus_res->start &&
 		    e->bus_end >= bus_res->end) {
 			root->mcfg_addr = e->addr;
 		}
-- 
1.9.1