[v2,1/2] PCI: endpoint: Fix API pci_epc_destroy() releasing domain_nr ID faults

Commit Message

Zijun Hu Nov. 7, 2024, 12:53 a.m. UTC

From: Zijun Hu <[e-mail]>

pci_epc_destroy() invokes pci_bus_release_domain_nr() to release domain_nr
ID, but the invocation has below 2 faults:

- The later accesses device @epc->dev which has been kfree()ed by previous
  device_unregister(), namely, it is a UAF issue.

- The later frees the domain_nr ID into @epc->dev, but the ID is actually
  allocated from @epc->dev.parent, so it will destroy domain_nr IDA.

Fix by freeing the ID to @epc->dev.parent before unregistering @epc->dev.

The file(s) affected are shown below since they indirectly use the API.
drivers/pci/controller/cadence/pcie-cadence-ep.c
drivers/pci/controller/dwc/pcie-designware-ep.c
drivers/pci/controller/pcie-rockchip-ep.c
drivers/pci/controller/pcie-rcar-ep.c

Fixes: 0328947c5032 ("PCI: endpoint: Assign PCI domain number for endpoint controllers")
Cc: Lorenzo Pieralisi <[e-mail]>
Cc: Jingoo Han <[e-mail]>
Cc: Marek Vasut <[e-mail]>
Cc: Yoshihiro Shimoda <[e-mail]>
Cc: Shawn Lin <[e-mail]>
Cc: Heiko Stuebner <[e-mail]>
Cc: [e-mail]
Signed-off-by: Zijun Hu <[e-mail]>
---
 drivers/pci/endpoint/pci-epc-core.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Manivannan Sadhasivam Nov. 12, 2024, 7:03 a.m. UTC | #1

On Thu, Nov 07, 2024 at 08:53:08AM +0800, Zijun Hu wrote:
> From: Zijun Hu <[e-mail]>
> 
> pci_epc_destroy() invokes pci_bus_release_domain_nr() to release domain_nr
> ID, but the invocation has below 2 faults:
> 
> - The later accesses device @epc->dev which has been kfree()ed by previous
>   device_unregister(), namely, it is a UAF issue.
> 
> - The later frees the domain_nr ID into @epc->dev, but the ID is actually
>   allocated from @epc->dev.parent, so it will destroy domain_nr IDA.
> 
> Fix by freeing the ID to @epc->dev.parent before unregistering @epc->dev.
> 
> The file(s) affected are shown below since they indirectly use the API.
> drivers/pci/controller/cadence/pcie-cadence-ep.c
> drivers/pci/controller/dwc/pcie-designware-ep.c
> drivers/pci/controller/pcie-rockchip-ep.c
> drivers/pci/controller/pcie-rcar-ep.c

No need to mention the callers.

> 
> Fixes: 0328947c5032 ("PCI: endpoint: Assign PCI domain number for endpoint controllers")
> Cc: Lorenzo Pieralisi <[e-mail]>
> Cc: Jingoo Han <[e-mail]>
> Cc: Marek Vasut <[e-mail]>
> Cc: Yoshihiro Shimoda <[e-mail]>
> Cc: Shawn Lin <[e-mail]>
> Cc: Heiko Stuebner <[e-mail]>
> Cc: [e-mail]
> Signed-off-by: Zijun Hu <[e-mail]>

Good catch! (not sure how I messed up in first place).

Reviewed-by: Manivannan Sadhasivam <[e-mail]>

- Mani

> ---
>  drivers/pci/endpoint/pci-epc-core.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 17f007109255..bcc9bc3d6df5 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -837,11 +837,10 @@ EXPORT_SYMBOL_GPL(pci_epc_bus_master_enable_notify);
>  void pci_epc_destroy(struct pci_epc *epc)
>  {
>  	pci_ep_cfs_remove_epc_group(epc->group);
> -	device_unregister(&epc->dev);
> -
>  #ifdef CONFIG_PCI_DOMAINS_GENERIC
> -	pci_bus_release_domain_nr(&epc->dev, epc->domain_nr);
> +	pci_bus_release_domain_nr(epc->dev.parent, epc->domain_nr);
>  #endif
> +	device_unregister(&epc->dev);
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_destroy);
>  
> 
> -- 
> 2.34.1
>

quic_zijuhu Nov. 12, 2024, 7:18 a.m. UTC | #2

On 11/12/2024 3:03 PM, Manivannan Sadhasivam wrote:
> On Thu, Nov 07, 2024 at 08:53:08AM +0800, Zijun Hu wrote:
>> From: Zijun Hu <[e-mail]>
>>
>> pci_epc_destroy() invokes pci_bus_release_domain_nr() to release domain_nr
>> ID, but the invocation has below 2 faults:
>>
>> - The later accesses device @epc->dev which has been kfree()ed by previous
>>   device_unregister(), namely, it is a UAF issue.
>>
>> - The later frees the domain_nr ID into @epc->dev, but the ID is actually
>>   allocated from @epc->dev.parent, so it will destroy domain_nr IDA.
>>
>> Fix by freeing the ID to @epc->dev.parent before unregistering @epc->dev.
>>
>> The file(s) affected are shown below since they indirectly use the API.
>> drivers/pci/controller/cadence/pcie-cadence-ep.c
>> drivers/pci/controller/dwc/pcie-designware-ep.c
>> drivers/pci/controller/pcie-rockchip-ep.c
>> drivers/pci/controller/pcie-rcar-ep.c
> 
> No need to mention the callers.
> 

thank you Manivannan for code review.
good suggestions, i will take them for further similar patches.(^^)

>>
>> Fixes: 0328947c5032 ("PCI: endpoint: Assign PCI domain number for endpoint controllers")
>> Cc: Lorenzo Pieralisi <[e-mail]>
>> Cc: Jingoo Han <[e-mail]>
>> Cc: Marek Vasut <[e-mail]>
>> Cc: Yoshihiro Shimoda <[e-mail]>
>> Cc: Shawn Lin <[e-mail]>
>> Cc: Heiko Stuebner <[e-mail]>
>> Cc: [e-mail]
>> Signed-off-by: Zijun Hu <[e-mail]>
> 
> Good catch! (not sure how I messed up in first place).
> 
> Reviewed-by: Manivannan Sadhasivam <[e-mail]>
> 
> - Mani
> 
>> ---

[snip]

>>
>

Patch

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 17f007109255..bcc9bc3d6df5 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -837,11 +837,10 @@  EXPORT_SYMBOL_GPL(pci_epc_bus_master_enable_notify);
 void pci_epc_destroy(struct pci_epc *epc)
 {
 	pci_ep_cfs_remove_epc_group(epc->group);
-	device_unregister(&epc->dev);
-
 #ifdef CONFIG_PCI_DOMAINS_GENERIC
-	pci_bus_release_domain_nr(&epc->dev, epc->domain_nr);
+	pci_bus_release_domain_nr(epc->dev.parent, epc->domain_nr);
 #endif
+	device_unregister(&epc->dev);
 }
 EXPORT_SYMBOL_GPL(pci_epc_destroy);