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 --- drivers/reset/reset-ath79.c | 127 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 drivers/reset/reset-ath79.c (limited to 'drivers/reset/reset-ath79.c') diff --git a/drivers/reset/reset-ath79.c b/drivers/reset/reset-ath79.c new file mode 100644 index 000000000..1a2c0f8a5 --- /dev/null +++ b/drivers/reset/reset-ath79.c @@ -0,0 +1,127 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * AR71xx Reset Controller Driver + * Author: Alban Bedel + * + * Copyright (C) 2015 Alban Bedel + */ + +#include +#include +#include +#include +#include + +struct ath79_reset { + struct reset_controller_dev rcdev; + void __iomem *base; + spinlock_t lock; +}; + +#define FULL_CHIP_RESET 24 + +static int ath79_reset_update(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct ath79_reset *ath79_reset = + container_of(rcdev, struct ath79_reset, rcdev); + unsigned long flags; + u32 val; + + spin_lock_irqsave(&ath79_reset->lock, flags); + val = readl(ath79_reset->base); + if (assert) + val |= BIT(id); + else + val &= ~BIT(id); + writel(val, ath79_reset->base); + spin_unlock_irqrestore(&ath79_reset->lock, flags); + + return 0; +} + +static int ath79_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return ath79_reset_update(rcdev, id, true); +} + +static int ath79_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return ath79_reset_update(rcdev, id, false); +} + +static int ath79_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct ath79_reset *ath79_reset = + container_of(rcdev, struct ath79_reset, rcdev); + u32 val; + + val = readl(ath79_reset->base); + + return !!(val & BIT(id)); +} + +static const struct reset_control_ops ath79_reset_ops = { + .assert = ath79_reset_assert, + .deassert = ath79_reset_deassert, + .status = ath79_reset_status, +}; + +static int ath79_reset_restart_handler(struct sys_off_data *data) +{ + struct ath79_reset *ath79_reset = data->cb_data; + + ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET); + + return NOTIFY_DONE; +} + +static int ath79_reset_probe(struct platform_device *pdev) +{ + struct ath79_reset *ath79_reset; + int err; + + ath79_reset = devm_kzalloc(&pdev->dev, + sizeof(*ath79_reset), GFP_KERNEL); + if (!ath79_reset) + return -ENOMEM; + + ath79_reset->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ath79_reset->base)) + return PTR_ERR(ath79_reset->base); + + spin_lock_init(&ath79_reset->lock); + ath79_reset->rcdev.ops = &ath79_reset_ops; + ath79_reset->rcdev.owner = THIS_MODULE; + ath79_reset->rcdev.of_node = pdev->dev.of_node; + ath79_reset->rcdev.of_reset_n_cells = 1; + ath79_reset->rcdev.nr_resets = 32; + + err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev); + if (err) + return err; + + err = devm_register_restart_handler(&pdev->dev, ath79_reset_restart_handler, ath79_reset); + if (err) + dev_warn(&pdev->dev, "Failed to register restart handler\n"); + + return 0; +} + +static const struct of_device_id ath79_reset_dt_ids[] = { + { .compatible = "qca,ar7100-reset", }, + { }, +}; + +static struct platform_driver ath79_reset_driver = { + .probe = ath79_reset_probe, + .driver = { + .name = "ath79-reset", + .of_match_table = ath79_reset_dt_ids, + .suppress_bind_attrs = true, + }, +}; +builtin_platform_driver(ath79_reset_driver); -- cgit v1.3.1