[PATCH 4.19 180/346] PCI: Bounds-check command-line resource alignment requests

Greg Kroah-Hartman
2020-12-28T13:29:05Z

From: Bjorn Helgaas <bhelgaas@google.com>

[ Upstream commit 6534aac198b58309ff2337981d3f893e0be1d19d ]

32-bit BARs are limited to 2GB size (2^31). By extension, I assume 64-bit
BARs are limited to 2^63 bytes. Limit the alignment requested by the
"pci=resource_alignment=" command-line parameter to 2^63.

Link: https://lore.kernel.org/r/20201007123045.GS4282@kadam
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/pci.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 57a87a001b4f4..5103d4b140ee3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5840,19 +5840,21 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
while (*p) {
count = 0;
if (sscanf(p, "%d%n", &align_order, &count) == 1 &&
- p[count] == '@') {
+ p[count] == '@') {
p += count + 1;
+ if (align_order > 63) {
+ pr_err("PCI: Invalid requested alignment (order %d)\n",
+ align_order);
+ align_order = PAGE_SHIFT;
+ }
} else {
- align_order = -1;
+ align_order = PAGE_SHIFT;
}

ret = pci_dev_str_match(dev, p, &p);
if (ret == 1) {
*resize = true;
- if (align_order == -1)
- align = PAGE_SIZE;
- else
- align = 1 << align_order;
+ align = 1 << align_order;
break;
} else if (ret < 0) {
pr_err("PCI: Can't parse resource_alignment parameter: %s\n",
--
2.27.0