Commit a0af3d11 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

PCI/MSI: Prevent UAF in error path 



When the core MSI allocation fails, then the PCI/MSI code uses an already
freed MSI descriptor to unmask the MSI mask register in order to bring it back
into reset state.

Remove MSI_FLAG_FREE_MSI_DESCS from the PCI/MSI irqdomain flags and let the
PCI/MSI code free the MSI descriptors after usage.

Fixes: 0f62d941 ("genirq/msi: Provide msi_domain_alloc/free_irqs_descs_locked()")
Reported-by: default avatarTong Zhang <ztong0001@gmail.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarTong Zhang <ztong0001@gmail.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/87r1938vbn.ffs@tglx
parent 1d1df41c

drivers/pci/msi/irqdomain.c

+2 −2
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ void pci_msi_teardown_msi_irqs(struct pci_dev *dev) 
		msi_domain_free_irqs_descs_locked(domain, &dev->dev);

	else

		pci_msi_legacy_teardown_msi_irqs(dev);

	msi_free_msi_descs(&dev->dev);

}



/**
@@ -171,8 +172,7 @@ struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode, 
	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)

		pci_msi_domain_update_chip_ops(info);



	info->flags |= MSI_FLAG_ACTIVATE_EARLY | MSI_FLAG_DEV_SYSFS |

		       MSI_FLAG_FREE_MSI_DESCS;

	info->flags |= MSI_FLAG_ACTIVATE_EARLY | MSI_FLAG_DEV_SYSFS;

	if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))

		info->flags |= MSI_FLAG_MUST_REACTIVATE;

drivers/pci/msi/legacy.c

+0 −1
Original line number Diff line number Diff line
@@ -77,5 +77,4 @@ void pci_msi_legacy_teardown_msi_irqs(struct pci_dev *dev) 
{

	msi_device_destroy_sysfs(&dev->dev);

	arch_teardown_msi_irqs(dev);

	msi_free_msi_descs(&dev->dev);

}