Re: [PATCH 11/21] hw/ipmi: Fix latent realize() error handling bugs

[Corey Minyard]

On Sat, Nov 30, 2019 at 08:42:30PM +0100, Markus Armbruster wrote:
> isa_ipmi_bt_realize(), ipmi_isa_realize(), pci_ipmi_bt_realize(), and
> pci_ipmi_kcs_realize() crash when IPMIInterfaceClass method init()
> fails and their @errp argument is null.  First messed up 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".
> 
> The bug can't bite as no caller actually passes null, and none of the
> init() methods can actually fail.  Fix it anyway.

Well, whatever.  It looks correct and is better style.  I've added this
to my tree.

-corey

> 
> Cc: Corey Minyard <address@hidden>
> Signed-off-by: Markus Armbruster <address@hidden>
> ---
>  hw/ipmi/isa_ipmi_bt.c  | 7 +++++--
>  hw/ipmi/isa_ipmi_kcs.c | 7 +++++--
>  hw/ipmi/pci_ipmi_bt.c  | 6 ++++--
>  hw/ipmi/pci_ipmi_kcs.c | 6 ++++--
>  4 files changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/ipmi/isa_ipmi_bt.c b/hw/ipmi/isa_ipmi_bt.c
> index 9a87ffd3f0..9fba5ed383 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 ca3ea36a3f..cc6bd817f2 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 6ed925a665..ba9cf016b5 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 eeba63baa4..99f46152f4 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);
> -- 
> 2.21.0
>