Subject: Re: [PATCH] powernv: eeh: fix possible buffer overrun in ioda_eeh_phb_diag()

From: Gavin Shan <[email-masked]>
Date: Fri, 20 Dec 2013 09:59:37 +0800

On Fri, Dec 20, 2013 at 09:35:39AM +0800, Gavin Shan wrote:
>On Thu, Dec 19, 2013 at 05:14:07PM -0600, Brian W Hart wrote:
>>PHB diagnostic buffer may be smaller than PAGE_SIZE, especially when
>>PAGE_SIZE > 4KB.
>>
>
>I think you're talking about that PAGE_SIZE could be configured
>to have variable size (e.g. 4KB). So it's not safe to pass PAGE_SIZE
>to OPAL API opal_pci_get_phb_diag_data2(). Instead, we should pass
>PNV_PCI_DIAG_BUF_SIZE and it makes sense to me :-)
>
>Also, it needs to be backported to stable kernel as well.
>
>>Signed-off-by: Brian W Hart <[email-masked]>
>
>Acked-by: Gavin Shan <[email-masked]>
>

Sorry, Brian. It has been fixed as part of the following commit, which
has been put into Ben's powerpc-next branch :-)

commit 93aef2a789778e7ec787179fc9b34ca4885a5ef3

    161  static void ioda_eeh_phb_diag(struct pci_controller *hose)
    162  {
    163         struct pnv_phb *phb = hose->private_data;
    164 -       struct OpalIoPhbErrorCommon *common;
    165         long rc;
    166  
    167 -       common = (struct OpalIoPhbErrorCommon *)phb->diag.blob;
    168 -       rc = opal_pci_get_phb_diag_data2(phb->opal_id, common, PAGE_SIZE);
    169 +       rc = opal_pci_get_phb_diag_data2(phb->opal_id, phb->diag.blob,
    170 +                                        PNV_PCI_DIAG_BUF_SIZE);

>>---
>> arch/powerpc/platforms/powernv/eeh-ioda.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
>>index 02245ce..8184ef5 100644
>>--- a/arch/powerpc/platforms/powernv/eeh-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/eeh-ioda.c
>>@@ -820,14 +820,15 @@ static void ioda_eeh_phb_diag(struct pci_controller *hose)
>> 	struct OpalIoPhbErrorCommon *common;
>> 	long rc;
>>
>>-	common = (struct OpalIoPhbErrorCommon *)phb->diag.blob;
>>-	rc = opal_pci_get_phb_diag_data2(phb->opal_id, common, PAGE_SIZE);
>>+	rc = opal_pci_get_phb_diag_data2(phb->opal_id, phb->diag.blob,
>>+					 PNV_PCI_DIAG_BUF_SIZE);
>> 	if (rc != OPAL_SUCCESS) {
>> 		pr_warning("%s: Failed to get diag-data for PHB#%x (%ld)\n",
>> 			    __func__, hose->global_number, rc);
>> 		return;
>> 	}
>>
>>+	common = (struct OpalIoPhbErrorCommon *)phb->diag.blob;
>> 	switch (common->ioType) {
>> 	case OPAL_PHB_ERROR_DATA_TYPE_P7IOC:
>> 		ioda_eeh_p7ioc_phb_diag(hose, common);
>

Thanks,
Gavin