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From: Colin King <colin.king@canonical.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-pci@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] x86/PCI: Fix Broadcom CNB20LE unintended sign extension (redux)
Date: Thu, 25 Oct 2018 14:52:31 +0100	[thread overview]
Message-ID: <20181025135231.27817-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

In the expression "word1 << 16", word1 starts as u16, but is promoted to
a signed int, then sign-extended to resource_size_t, which is probably
not what was intended.  Cast to resource_size_t to avoid the sign
extension.

This fixes an identical issue as fixed by commit 0b2d70764bb3
("x86/PCI: Fix Broadcom CNB20LE unintended sign extension") back in 2014.

Detected by CoverityScan, CID#138749, 138750 ("Unintended sign extension")

Fixes: 3f6ea84a3035 ("PCI: read memory ranges out of Broadcom CNB20LE host bridge")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 arch/x86/pci/broadcom_bus.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/broadcom_bus.c b/arch/x86/pci/broadcom_bus.c
index 526536c81ddc..d09c401a300d 100644
--- a/arch/x86/pci/broadcom_bus.c
+++ b/arch/x86/pci/broadcom_bus.c
@@ -50,8 +50,8 @@ static void __init cnb20le_res(u8 bus, u8 slot, u8 func)
 	word1 = read_pci_config_16(bus, slot, func, 0xc0);
 	word2 = read_pci_config_16(bus, slot, func, 0xc2);
 	if (word1 != word2) {
-		res.start = (word1 << 16) | 0x0000;
-		res.end   = (word2 << 16) | 0xffff;
+		res.start = ((resource_size_t) word1 << 16) | 0x0000;
+		res.end   = ((resource_size_t) word2 << 16) | 0xffff;
 		res.flags = IORESOURCE_MEM;
 		update_res(info, res.start, res.end, res.flags, 0);
 	}
-- 
2.19.1


WARNING: multiple messages have this Message-ID (diff)
From: Colin King <colin.king@canonical.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-pci@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] x86/PCI: Fix Broadcom CNB20LE unintended sign extension (redux)
Date: Thu, 25 Oct 2018 13:52:31 +0000	[thread overview]
Message-ID: <20181025135231.27817-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

In the expression "word1 << 16", word1 starts as u16, but is promoted to
a signed int, then sign-extended to resource_size_t, which is probably
not what was intended.  Cast to resource_size_t to avoid the sign
extension.

This fixes an identical issue as fixed by commit 0b2d70764bb3
("x86/PCI: Fix Broadcom CNB20LE unintended sign extension") back in 2014.

Detected by CoverityScan, CID#138749, 138750 ("Unintended sign extension")

Fixes: 3f6ea84a3035 ("PCI: read memory ranges out of Broadcom CNB20LE host bridge")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 arch/x86/pci/broadcom_bus.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/broadcom_bus.c b/arch/x86/pci/broadcom_bus.c
index 526536c81ddc..d09c401a300d 100644
--- a/arch/x86/pci/broadcom_bus.c
+++ b/arch/x86/pci/broadcom_bus.c
@@ -50,8 +50,8 @@ static void __init cnb20le_res(u8 bus, u8 slot, u8 func)
 	word1 = read_pci_config_16(bus, slot, func, 0xc0);
 	word2 = read_pci_config_16(bus, slot, func, 0xc2);
 	if (word1 != word2) {
-		res.start = (word1 << 16) | 0x0000;
-		res.end   = (word2 << 16) | 0xffff;
+		res.start = ((resource_size_t) word1 << 16) | 0x0000;
+		res.end   = ((resource_size_t) word2 << 16) | 0xffff;
 		res.flags = IORESOURCE_MEM;
 		update_res(info, res.start, res.end, res.flags, 0);
 	}
-- 
2.19.1

             reply	other threads:[~2018-10-25 13:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-25 13:52 Colin King [this message]
2018-10-25 13:52 ` [PATCH] x86/PCI: Fix Broadcom CNB20LE unintended sign extension (redux) Colin King
2018-11-09  0:02 ` Bjorn Helgaas
2018-11-09  0:02   ` Bjorn Helgaas

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