net/smc: fix access to parent of an ib device

The parent of an ib device is used to retrieve the PCI device attributes. It turns out that there are possible cases when an ib device has no parent set in the device structure, which may lead to page faults when trying to access this memory. Fix that by checking the parent pointer and consolidate the pci device specific processing in a new function. Fixes: a3db10e ("net/smc: Add support for obtaining SMCR device list") Reported-by: [email protected] Signed-off-by: Karsten Graul <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
berg · Dec 16, 2020 · 995433b · 995433b
1 parent ef72cd3
commit 995433b
Showing 1 changed file with 23 additions and 13 deletions.
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
@@ -394,6 +394,22 @@ static int smc_nl_handle_dev_port(struct sk_buff *skb,
 	return -EMSGSIZE;
 }
 
+static bool smc_nl_handle_pci_values(const struct smc_pci_dev *smc_pci_dev,
+				     struct sk_buff *skb)
+{
+	if (nla_put_u32(skb, SMC_NLA_DEV_PCI_FID, smc_pci_dev->pci_fid))
+		return false;
+	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_CHID, smc_pci_dev->pci_pchid))
+		return false;
+	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_VENDOR, smc_pci_dev->pci_vendor))
+		return false;
+	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_DEVICE, smc_pci_dev->pci_device))
+		return false;
+	if (nla_put_string(skb, SMC_NLA_DEV_PCI_ID, smc_pci_dev->pci_id))
+		return false;
+	return true;
+}
+
 static int smc_nl_handle_smcr_dev(struct smc_ib_device *smcibdev,
 				  struct sk_buff *skb,
 				  struct netlink_callback *cb)
@@ -417,19 +433,13 @@ static int smc_nl_handle_smcr_dev(struct smc_ib_device *smcibdev,
 	is_crit = smcr_diag_is_dev_critical(&smc_lgr_list, smcibdev);
 	if (nla_put_u8(skb, SMC_NLA_DEV_IS_CRIT, is_crit))
 		goto errattr;
-	memset(&smc_pci_dev, 0, sizeof(smc_pci_dev));
-	pci_dev = to_pci_dev(smcibdev->ibdev->dev.parent);
-	smc_set_pci_values(pci_dev, &smc_pci_dev);
-	if (nla_put_u32(skb, SMC_NLA_DEV_PCI_FID, smc_pci_dev.pci_fid))
-		goto errattr;
-	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_CHID, smc_pci_dev.pci_pchid))
-		goto errattr;
-	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_VENDOR, smc_pci_dev.pci_vendor))
-		goto errattr;
-	if (nla_put_u16(skb, SMC_NLA_DEV_PCI_DEVICE, smc_pci_dev.pci_device))
-		goto errattr;
-	if (nla_put_string(skb, SMC_NLA_DEV_PCI_ID, smc_pci_dev.pci_id))
-		goto errattr;
+	if (smcibdev->ibdev->dev.parent) {
+		memset(&smc_pci_dev, 0, sizeof(smc_pci_dev));
+		pci_dev = to_pci_dev(smcibdev->ibdev->dev.parent);
+		smc_set_pci_values(pci_dev, &smc_pci_dev);
+		if (!smc_nl_handle_pci_values(&smc_pci_dev, skb))
+			goto errattr;
+	}
 	snprintf(smc_ibname, sizeof(smc_ibname), "%s", smcibdev->ibdev->name);
 	if (nla_put_string(skb, SMC_NLA_DEV_IB_NAME, smc_ibname))
 		goto errattr;