hw/ipmi: Fix realize() error API violations

isa_ipmi_bt_realize(), ipmi_isa_realize(), pci_ipmi_bt_realize(), and
pci_ipmi_kcs_realize() dereference @errp when IPMIInterfaceClass
method init() fails.  That's wrong; see the big comment in error.h.
Introduced in commit 0719029c47 "ipmi: Add an ISA KCS low-level
interface", then imitated in commit a9b74079cb "ipmi: Add a BT
low-level interface" and commit 12f983c6aa "ipmi: Add PCI IPMI
interfaces".

No caller actually passes null.

Fix anyway: splice in a local Error *err, and error_propagate().

Cc: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20191204093625.14836-9-armbru@redhat.com>

4 files changed, 18 insertions, 8 deletions

diff --git a/hw/ipmi/isa_ipmi_bt.c b/hw/ipmi/isa_ipmi_bt.c
index 9a87ffd..9fba5ed 100644
--- a/hw/ipmi/isa_ipmi_bt.c
+++ b/hw/ipmi/isa_ipmi_bt.c
@@ -70,6 +70,7 @@ static void isa_ipmi_bt_lower_irq(IPMIBT *ib)
 
 static void isa_ipmi_bt_realize(DeviceState *dev, Error **errp)
 {
+    Error *err = NULL;
     ISADevice *isadev = ISA_DEVICE(dev);
     ISAIPMIBTDevice *iib = ISA_IPMI_BT(dev);
     IPMIInterface *ii = IPMI_INTERFACE(dev);
@@ -85,9 +86,11 @@ static void isa_ipmi_bt_realize(DeviceState *dev, Error **errp)
     iib->bt.bmc->intf = ii;
     iib->bt.opaque = iib;
 
-    iic->init(ii, 0, errp);
-    if (*errp)
+    iic->init(ii, 0, &err);
+    if (err) {
+        error_propagate(errp, err);
         return;
+    }
 
     if (iib->isairq > 0) {
         isa_init_irq(isadev, &iib->irq, iib->isairq);
diff --git a/hw/ipmi/isa_ipmi_kcs.c b/hw/ipmi/isa_ipmi_kcs.c
index ca3ea36..cc6bd81 100644
--- a/hw/ipmi/isa_ipmi_kcs.c
+++ b/hw/ipmi/isa_ipmi_kcs.c
@@ -69,6 +69,7 @@ static void isa_ipmi_kcs_lower_irq(IPMIKCS *ik)
 
 static void ipmi_isa_realize(DeviceState *dev, Error **errp)
 {
+    Error *err = NULL;
     ISADevice *isadev = ISA_DEVICE(dev);
     ISAIPMIKCSDevice *iik = ISA_IPMI_KCS(dev);
     IPMIInterface *ii = IPMI_INTERFACE(dev);
@@ -84,9 +85,11 @@ static void ipmi_isa_realize(DeviceState *dev, Error **errp)
     iik->kcs.bmc->intf = ii;
     iik->kcs.opaque = iik;
 
-    iic->init(ii, 0, errp);
-    if (*errp)
+    iic->init(ii, 0, &err);
+    if (err) {
+        error_propagate(errp, err);
         return;
+    }
 
     if (iik->isairq > 0) {
         isa_init_irq(isadev, &iik->irq, iik->isairq);
diff --git a/hw/ipmi/pci_ipmi_bt.c b/hw/ipmi/pci_ipmi_bt.c
index 6ed925a..ba9cf01 100644
--- a/hw/ipmi/pci_ipmi_bt.c
+++ b/hw/ipmi/pci_ipmi_bt.c
@@ -54,6 +54,7 @@ static void pci_ipmi_lower_irq(IPMIBT *ik)
 
 static void pci_ipmi_bt_realize(PCIDevice *pd, Error **errp)
 {
+    Error *err = NULL;
     PCIIPMIBTDevice *pik = PCI_IPMI_BT(pd);
     IPMIInterface *ii = IPMI_INTERFACE(pd);
     IPMIInterfaceClass *iic = IPMI_INTERFACE_GET_CLASS(ii);
@@ -74,8 +75,9 @@ static void pci_ipmi_bt_realize(PCIDevice *pd, Error **errp)
     pik->bt.raise_irq = pci_ipmi_raise_irq;
     pik->bt.lower_irq = pci_ipmi_lower_irq;
 
-    iic->init(ii, 8, errp);
-    if (*errp) {
+    iic->init(ii, 8, &err);
+    if (err) {
+        error_propagate(errp, err);
         return;
     }
     pci_register_bar(pd, 0, PCI_BASE_ADDRESS_SPACE_IO, &pik->bt.io);
diff --git a/hw/ipmi/pci_ipmi_kcs.c b/hw/ipmi/pci_ipmi_kcs.c
index eeba63b..99f4615 100644
--- a/hw/ipmi/pci_ipmi_kcs.c
+++ b/hw/ipmi/pci_ipmi_kcs.c
@@ -54,6 +54,7 @@ static void pci_ipmi_lower_irq(IPMIKCS *ik)
 
 static void pci_ipmi_kcs_realize(PCIDevice *pd, Error **errp)
 {
+    Error *err = NULL;
     PCIIPMIKCSDevice *pik = PCI_IPMI_KCS(pd);
     IPMIInterface *ii = IPMI_INTERFACE(pd);
     IPMIInterfaceClass *iic = IPMI_INTERFACE_GET_CLASS(ii);
@@ -74,8 +75,9 @@ static void pci_ipmi_kcs_realize(PCIDevice *pd, Error **errp)
     pik->kcs.raise_irq = pci_ipmi_raise_irq;
     pik->kcs.lower_irq = pci_ipmi_lower_irq;
 
-    iic->init(ii, 8, errp);
-    if (*errp) {
+    iic->init(ii, 8, &err);
+    if (err) {
+        error_propagate(errp, err);
         return;
     }
     pci_register_bar(pd, 0, PCI_BASE_ADDRESS_SPACE_IO, &pik->kcs.io);