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| author | Xie Yuanbin <xieyuanbin1@huawei.com> | 2026-07-28 03:16:42 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2026-08-05 16:15:51 +0100 |
| commit | 1039bffd6ae9c75b42b7d148d6c1106134107b66 (patch) | |
| tree | e8ee4ac80f87e2ad1b6b0c877eccbb62b0915c02 /security/ipe/Makefile | |
| download | linux-stable-1039bffd6ae9c75b42b7d148d6c1106134107b66.tar.gz linux-stable-1039bffd6ae9c75b42b7d148d6c1106134107b66.zip | |
ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted
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 <xiqi2@huawei.com>
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) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'security/ipe/Makefile')
| -rw-r--r-- | security/ipe/Makefile | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/security/ipe/Makefile b/security/ipe/Makefile new file mode 100644 index 000000000..2ffabfa63 --- /dev/null +++ b/security/ipe/Makefile @@ -0,0 +1,31 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. +# +# Makefile for building the IPE module as part of the kernel tree. +# + +quiet_cmd_polgen = IPE_POL $(2) + cmd_polgen = scripts/ipe/polgen/polgen security/ipe/boot_policy.c $(2) + +targets += boot_policy.c + +$(obj)/boot_policy.c: scripts/ipe/polgen/polgen $(CONFIG_IPE_BOOT_POLICY) FORCE + $(call if_changed,polgen,$(CONFIG_IPE_BOOT_POLICY)) + +obj-$(CONFIG_SECURITY_IPE) += \ + boot_policy.o \ + digest.o \ + eval.o \ + hooks.o \ + fs.o \ + ipe.o \ + policy.o \ + policy_fs.o \ + policy_parser.o \ + audit.o \ + +clean-files := boot_policy.c \ + +obj-$(CONFIG_SECURITY_IPE_KUNIT_TEST) += \ + policy_tests.o \ |