From 1039bffd6ae9c75b42b7d148d6c1106134107b66 Mon Sep 17 00:00:00 2001 From: Xie Yuanbin Date: Tue, 28 Jul 2026 03:16:42 +0100 Subject: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock. Co-developed-by: Qi Xi Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults") Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com Acked-by: Lorenzo Stoakes (ARM) Reviewed-by: Linus Walleij Signed-off-by: Qi Xi Signed-off-by: Xie Yuanbin Signed-off-by: Russell King --- include/crypto/internal/engine.h | 58 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 include/crypto/internal/engine.h (limited to 'include/crypto/internal/engine.h') diff --git a/include/crypto/internal/engine.h b/include/crypto/internal/engine.h new file mode 100644 index 000000000..6a1d27880 --- /dev/null +++ b/include/crypto/internal/engine.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Crypto engine API + * + * Copyright (c) 2016 Baolin Wang + * Copyright (c) 2023 Herbert Xu + */ +#ifndef _CRYPTO_INTERNAL_ENGINE_H +#define _CRYPTO_INTERNAL_ENGINE_H + +#include +#include +#include +#include +#include + +#define ENGINE_NAME_LEN 30 + +struct device; + +/* + * struct crypto_engine - crypto hardware engine + * @name: the engine name + * @busy: request pump is busy + * @running: the engine is on working + * @retry_support: indication that the hardware allows re-execution + * of a failed backlog request + * crypto-engine, in head position to keep order + * @rt: whether this queue is set to run as a realtime task + * @list: link with the global crypto engine list + * @queue_lock: spinlock to synchronise access to request queue + * @queue: the crypto queue of the engine + * @kworker: kthread worker struct for request pump + * @pump_requests: work struct for scheduling work to the request pump + * @priv_data: the engine private data + * @cur_req: the current request which is on processing + */ +struct crypto_engine { + char name[ENGINE_NAME_LEN]; + bool busy; + bool running; + + bool retry_support; + bool rt; + + struct list_head list; + spinlock_t queue_lock; + struct crypto_queue queue __guarded_by(&queue_lock); + struct device *dev; + + struct kthread_worker *kworker; + struct kthread_work pump_requests; + + void *priv_data; + struct crypto_async_request *cur_req; +}; + +#endif -- cgit v1.3.1