From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- net/devres.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 net/devres.c (limited to 'net/devres.c') diff --git a/net/devres.c b/net/devres.c new file mode 100644 index 000000000..5ccf6ca31 --- /dev/null +++ b/net/devres.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * This file contains all networking devres helpers. + */ + +#include +#include +#include + +struct net_device_devres { + struct net_device *ndev; +}; + +static void devm_free_netdev(struct device *dev, void *this) +{ + struct net_device_devres *res = this; + + free_netdev(res->ndev); +} + +struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv, + unsigned int txqs, unsigned int rxqs) +{ + struct net_device_devres *dr; + + dr = devres_alloc(devm_free_netdev, sizeof(*dr), GFP_KERNEL); + if (!dr) + return NULL; + + dr->ndev = alloc_etherdev_mqs(sizeof_priv, txqs, rxqs); + if (!dr->ndev) { + devres_free(dr); + return NULL; + } + + devres_add(dev, dr); + + return dr->ndev; +} +EXPORT_SYMBOL(devm_alloc_etherdev_mqs); + +static void devm_unregister_netdev(struct device *dev, void *this) +{ + struct net_device_devres *res = this; + + unregister_netdev(res->ndev); +} + +static int netdev_devres_match(struct device *dev, void *this, void *match_data) +{ + struct net_device_devres *res = this; + struct net_device *ndev = match_data; + + return ndev == res->ndev; +} + +/** + * devm_register_netdev - resource managed variant of register_netdev() + * @dev: managing device for this netdev - usually the parent device + * @ndev: device to register + * + * This is a devres variant of register_netdev() for which the unregister + * function will be called automatically when the managing device is + * detached. Note: the net_device used must also be resource managed by + * the same struct device. + */ +int devm_register_netdev(struct device *dev, struct net_device *ndev) +{ + struct net_device_devres *dr; + int ret; + + /* struct net_device must itself be managed. For now a managed netdev + * can only be allocated by devm_alloc_etherdev_mqs() so the check is + * straightforward. + */ + if (WARN_ON(!devres_find(dev, devm_free_netdev, + netdev_devres_match, ndev))) + return -EINVAL; + + dr = devres_alloc(devm_unregister_netdev, sizeof(*dr), GFP_KERNEL); + if (!dr) + return -ENOMEM; + + ret = register_netdev(ndev); + if (ret) { + devres_free(dr); + return ret; + } + + dr->ndev = ndev; + devres_add(ndev->dev.parent, dr); + + return 0; +} +EXPORT_SYMBOL(devm_register_netdev); -- cgit v1.3.1