PCI: Bounds-check command-line resource alignment requests

[ 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>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e578d34..b7a860e 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6202,19 +6202,21 @@ 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",