6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Danilo Krummrich [ Upstream commit 10a4206a24013be4d558d476010cbf2eb4c9fa64 ] When a driver is probed through __driver_attach(), the bus' match() callback is called without the device lock held, thus accessing the driver_override field without a lock, which can cause a UAF. Fix this by using the driver-core driver_override infrastructure taking care of proper locking internally. Note that calling match() from __driver_attach() without the device lock held is intentional. [1] Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1] Reported-by: Gui-Dong Han Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789 Fixes: 782a985d7af2 ("PCI: Introduce new device binding path using pci_dev.driver_override") Acked-by: Bjorn Helgaas Acked-by: Alex Williamson Tested-by: Gui-Dong Han Reviewed-by: Gui-Dong Han Link: https://patch.msgid.link/20260324005919.2408620-6-dakr@kernel.org Signed-off-by: Danilo Krummrich Signed-off-by: Sasha Levin --- drivers/pci/pci-driver.c | 11 +++++++---- drivers/pci/pci-sysfs.c | 28 ---------------------------- drivers/pci/probe.c | 1 - drivers/vfio/pci/vfio_pci_core.c | 4 ++-- drivers/xen/xen-pciback/pci_stub.c | 6 ++++-- include/linux/pci.h | 6 ------ 6 files changed, 13 insertions(+), 43 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index cfb8b81250db6..9b4a8bc416453 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -138,9 +138,11 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv, { struct pci_dynid *dynid; const struct pci_device_id *found_id = NULL, *ids; + int ret; /* When driver_override is set, only bind to the matching driver */ - if (dev->driver_override && strcmp(dev->driver_override, drv->name)) + ret = device_match_driver_override(&dev->dev, &drv->driver); + if (ret == 0) return NULL; /* Look at the dynamic ids first, before the static ones */ @@ -164,7 +166,7 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv, * matching. */ if (found_id->override_only) { - if (dev->driver_override) + if (ret > 0) return found_id; } else { return found_id; @@ -172,7 +174,7 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv, } /* driver_override will always match, send a dummy id */ - if (dev->driver_override) + if (ret > 0) return &pci_device_id_any; return NULL; } @@ -432,7 +434,7 @@ void __weak pcibios_free_irq(struct pci_dev *dev) static inline bool pci_device_can_probe(struct pci_dev *pdev) { return (!pdev->is_virtfn || pdev->physfn->sriov->drivers_autoprobe || - pdev->driver_override); + device_has_driver_override(&pdev->dev)); } #else static inline bool pci_device_can_probe(struct pci_dev *pdev) @@ -1683,6 +1685,7 @@ static void pci_dma_cleanup(struct device *dev) struct bus_type pci_bus_type = { .name = "pci", + .driver_override = true, .match = pci_bus_match, .uevent = pci_uevent, .probe = pci_device_probe, diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 346630f3a6f28..857bfe349cf5c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -608,33 +608,6 @@ static ssize_t devspec_show(struct device *dev, static DEVICE_ATTR_RO(devspec); #endif -static ssize_t driver_override_store(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) -{ - struct pci_dev *pdev = to_pci_dev(dev); - int ret; - - ret = driver_set_override(dev, &pdev->driver_override, buf, count); - if (ret) - return ret; - - return count; -} - -static ssize_t driver_override_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct pci_dev *pdev = to_pci_dev(dev); - ssize_t len; - - device_lock(dev); - len = sysfs_emit(buf, "%s\n", pdev->driver_override); - device_unlock(dev); - return len; -} -static DEVICE_ATTR_RW(driver_override); - static struct attribute *pci_dev_attrs[] = { &dev_attr_power_state.attr, &dev_attr_resource.attr, @@ -662,7 +635,6 @@ static struct attribute *pci_dev_attrs[] = { #ifdef CONFIG_OF &dev_attr_devspec.attr, #endif - &dev_attr_driver_override.attr, &dev_attr_ari_enabled.attr, NULL, }; diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index d90ffbb47f0e2..9701917ce8380 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2371,7 +2371,6 @@ static void pci_release_dev(struct device *dev) pci_release_of_node(pci_dev); pcibios_release_device(pci_dev); pci_bus_put(pci_dev->bus); - kfree(pci_dev->driver_override); bitmap_free(pci_dev->dma_alias_mask); dev_dbg(dev, "device released\n"); kfree(pci_dev); diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index db31aeb9df70c..76c252bf999fc 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -1938,8 +1938,8 @@ static int vfio_pci_bus_notifier(struct notifier_block *nb, pdev->is_virtfn && physfn == vdev->pdev) { pci_info(vdev->pdev, "Captured SR-IOV VF %s driver_override\n", pci_name(pdev)); - pdev->driver_override = kasprintf(GFP_KERNEL, "%s", - vdev->vdev.ops->name); + WARN_ON(device_set_driver_override(&pdev->dev, + vdev->vdev.ops->name)); } else if (action == BUS_NOTIFY_BOUND_DRIVER && pdev->is_virtfn && physfn == vdev->pdev) { struct pci_driver *drv = pci_dev_driver(pdev); diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c index e34b623e4b41f..42e630239b9b0 100644 --- a/drivers/xen/xen-pciback/pci_stub.c +++ b/drivers/xen/xen-pciback/pci_stub.c @@ -555,6 +555,8 @@ static int pcistub_seize(struct pci_dev *dev, return err; } +static struct pci_driver xen_pcibk_pci_driver; + /* Called when 'bind'. This means we must _NOT_ call pci_reset_function or * other functions that take the sysfs lock. */ static int pcistub_probe(struct pci_dev *dev, const struct pci_device_id *id) @@ -566,8 +568,8 @@ static int pcistub_probe(struct pci_dev *dev, const struct pci_device_id *id) match = pcistub_match(dev); - if ((dev->driver_override && - !strcmp(dev->driver_override, PCISTUB_DRIVER_NAME)) || + if (device_match_driver_override(&dev->dev, + &xen_pcibk_pci_driver.driver) > 0 || match) { if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL diff --git a/include/linux/pci.h b/include/linux/pci.h index db4d82aae1343..bef23297fb801 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -529,12 +529,6 @@ struct pci_dev { u16 acs_cap; /* ACS Capability offset */ phys_addr_t rom; /* Physical address if not from BAR */ size_t romlen; /* Length if not from BAR */ - /* - * Driver name to force a match. Do not set directly, because core - * frees it. Use driver_set_override() to set or clear it. - */ - const char *driver_override; - unsigned long priv_flags; /* Private flags for the PCI driver */ /* These methods index pci_reset_fn_methods[] */ -- 2.53.0