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* ACPI: Drop the custom_method debugfs interfaceRafael J. Wysocki2024-02-221-103/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ACPI custom_method debugfs interface is security-sensitive and concurrent access to it is broken [1]. Moreover, the recipe for preparing a customized version of a given control method has changed at one point due to ACPICA changes, which has not been reflected in its documentation, so whoever used it before has had to adapt and it had gone unnoticed for a long time. This interface was a bad idea to start with and its implementation is fragile at the design level. It's been always conceptually questionable, problematic from the security standpoint and implemented poorly. Patches fixing its most apparent functional issues (for example, [2]) don't actually address much of the above. Granted, at the time it was introduced, there was no alternative, but there is the AML debugger in the kernel now and there is the configfs interface allowing custom ACPI tables to be loaded. The former can be used for extensive AML debugging and the latter can be use for testing new AML. [3] Accordingly, drop custom_method along with its (outdated anyway) documentation. Link: https://lore.kernel.org/linux-acpi/20221227063335.61474-1-zh.nvgt@gmail.com/ # [1] Link: https://lore.kernel.org/linux-acpi/20231111132402.4142-1-shiqiang.deng213@gmail.com/ [2] Link: https://stackoverflow.com/questions/62849113/how-to-unload-an-overlay-loaded-using-acpi-config-sysfs # [3] Reported-by: Hang Zhang <zh.nvgt@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Zhang Rui <rui.zhang@intel.com> Reviewed-by: Kees Cook <keescook@chromium.org>
* ACPI: custom_method: fix a possible memory leakMark Langsdorf2021-04-281-0/+2
| | | | | | | | | | | | | | In cm_write(), if the 'buf' is allocated memory but not fully consumed, it is possible to reallocate the buffer without freeing it by passing '*ppos' as 0 on a subsequent call. Add an explicit kfree() before kzalloc() to prevent the possible memory leak. Fixes: 526b4af47f44 ("ACPI: Split out custom_method functionality into an own driver") Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: custom_method: fix potential use-after-free issueMark Langsdorf2021-04-281-1/+1
| | | | | | | | | | | | | | | | In cm_write(), buf is always freed when reaching the end of the function. If the requested count is less than table.length, the allocated buffer will be freed but subsequent calls to cm_write() will still try to access it. Remove the unconditional kfree(buf) at the end of the function and set the buf to NULL in the -EINVAL error path to match the rest of function. Fixes: 03d1571d9513 ("ACPI: custom_method: fix memory leaks") Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: custom_method: fix a coding style issueXiaofei Tan2021-04-081-1/+1
| | | | | | | | | | | Fix the following coding style issue reported by checkpatch.pl ERROR: "foo * bar" should be "foo *bar" FILE: drivers/acpi/custom_method.c:22: +static ssize_t cm_write(struct file *file, const char __user * user_buf, Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: custom_method: Remove dead ACPICA debug codeHanjun Guo2020-09-251-2/+0
| | | | | | | | | ACPICA debug code _COMPONENT and ACPI_MODULE_NAME() is not used in custom_method.c, remove it. Signed-off-by: Hanjun Guo <guohanjun@huawei.com> [ rjw: Subject edit ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge branch 'next-lockdown' of ↵Linus Torvalds2019-09-281-0/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull kernel lockdown mode from James Morris: "This is the latest iteration of the kernel lockdown patchset, from Matthew Garrett, David Howells and others. From the original description: This patchset introduces an optional kernel lockdown feature, intended to strengthen the boundary between UID 0 and the kernel. When enabled, various pieces of kernel functionality are restricted. Applications that rely on low-level access to either hardware or the kernel may cease working as a result - therefore this should not be enabled without appropriate evaluation beforehand. The majority of mainstream distributions have been carrying variants of this patchset for many years now, so there's value in providing a doesn't meet every distribution requirement, but gets us much closer to not requiring external patches. There are two major changes since this was last proposed for mainline: - Separating lockdown from EFI secure boot. Background discussion is covered here: https://lwn.net/Articles/751061/ - Implementation as an LSM, with a default stackable lockdown LSM module. This allows the lockdown feature to be policy-driven, rather than encoding an implicit policy within the mechanism. The new locked_down LSM hook is provided to allow LSMs to make a policy decision around whether kernel functionality that would allow tampering with or examining the runtime state of the kernel should be permitted. The included lockdown LSM provides an implementation with a simple policy intended for general purpose use. This policy provides a coarse level of granularity, controllable via the kernel command line: lockdown={integrity|confidentiality} Enable the kernel lockdown feature. If set to integrity, kernel features that allow userland to modify the running kernel are disabled. If set to confidentiality, kernel features that allow userland to extract confidential information from the kernel are also disabled. This may also be controlled via /sys/kernel/security/lockdown and overriden by kernel configuration. New or existing LSMs may implement finer-grained controls of the lockdown features. Refer to the lockdown_reason documentation in include/linux/security.h for details. The lockdown feature has had signficant design feedback and review across many subsystems. This code has been in linux-next for some weeks, with a few fixes applied along the way. Stephen Rothwell noted that commit 9d1f8be5cf42 ("bpf: Restrict bpf when kernel lockdown is in confidentiality mode") is missing a Signed-off-by from its author. Matthew responded that he is providing this under category (c) of the DCO" * 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits) kexec: Fix file verification on S390 security: constify some arrays in lockdown LSM lockdown: Print current->comm in restriction messages efi: Restrict efivar_ssdt_load when the kernel is locked down tracefs: Restrict tracefs when the kernel is locked down debugfs: Restrict debugfs when the kernel is locked down kexec: Allow kexec_file() with appropriate IMA policy when locked down lockdown: Lock down perf when in confidentiality mode bpf: Restrict bpf when kernel lockdown is in confidentiality mode lockdown: Lock down tracing and perf kprobes when in confidentiality mode lockdown: Lock down /proc/kcore x86/mmiotrace: Lock down the testmmiotrace module lockdown: Lock down module params that specify hardware parameters (eg. ioport) lockdown: Lock down TIOCSSERIAL lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down acpi: Disable ACPI table override if the kernel is locked down acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down ACPI: Limit access to custom_method when the kernel is locked down x86/msr: Restrict MSR access when the kernel is locked down x86: Lock down IO port access when the kernel is locked down ...
| * ACPI: Limit access to custom_method when the kernel is locked downMatthew Garrett2019-08-201-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | custom_method effectively allows arbitrary access to system memory, making it possible for an attacker to circumvent restrictions on module loading. Disable it if the kernel is locked down. Signed-off-by: Matthew Garrett <mjg59@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> cc: linux-acpi@vger.kernel.org Signed-off-by: James Morris <jmorris@namei.org>
* | ACPI: custom_method: fix memory leaksWenwen Wang2019-09-021-1/+4
|/ | | | | | | | | | In cm_write(), 'buf' is allocated through kzalloc(). In the following execution, if an error occurs, 'buf' is not deallocated, leading to memory leaks. To fix this issue, free 'buf' before returning the error. Fixes: 526b4af47f44 ("ACPI: Split out custom_method functionality into an own driver") Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* treewide: Add SPDX license identifier for more missed filesThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ACPI: no need to check return value of debugfs_create functionsGreg Kroah-Hartman2019-01-221-6/+0
| | | | | | | | | When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: custom_method: remove meaningless null check before debugfs_remove()zhong jiang2018-09-101-2/+1
| | | | | | | | debugfs_remove() has taken null pointer into account. So it is safe to remove the check before debugfs_remove(). Signed-off-by: zhong jiang <zhongjiang@huawei.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* treewide: Align function definition open/close bracesJoe Perches2018-03-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Some functions definitions have either the initial open brace and/or the closing brace outside of column 1. Move those braces to column 1. This allows various function analyzers like gnu complexity to work properly for these modified functions. Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Takashi Iwai <tiwai@suse.de> Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Nicolin Chen <nicoleotsuka@gmail.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* ACPI: Clean up inclusions of ACPI header filesLv Zheng2013-12-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace direct inclusions of <acpi/acpi.h>, <acpi/acpi_bus.h> and <acpi/acpi_drivers.h>, which are incorrect, with <linux/acpi.h> inclusions and remove some inclusions of those files that aren't necessary. First of all, <acpi/acpi.h>, <acpi/acpi_bus.h> and <acpi/acpi_drivers.h> should not be included directly from any files that are built for CONFIG_ACPI unset, because that generally leads to build warnings about undefined symbols in !CONFIG_ACPI builds. For CONFIG_ACPI set, <linux/acpi.h> includes those files and for CONFIG_ACPI unset it provides stub ACPI symbols to be used in that case. Second, there are ordering dependencies between those files that always have to be met. Namely, it is required that <acpi/acpi_bus.h> be included prior to <acpi/acpi_drivers.h> so that the acpi_pci_root declarations the latter depends on are always there. And <acpi/acpi.h> which provides basic ACPICA type declarations should always be included prior to any other ACPI headers in CONFIG_ACPI builds. That also is taken care of including <linux/acpi.h> as appropriate. Signed-off-by: Lv Zheng <lv.zheng@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Tony Luck <tony.luck@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> (drivers/pci stuff) Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> (Xen stuff) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge tag 'modules-next-for-linus' of ↵Linus Torvalds2013-02-261-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull module update from Rusty Russell: "The sweeping change is to make add_taint() explicitly indicate whether to disable lockdep, but it's a mechanical change." * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: MODSIGN: Add option to not sign modules during modules_install MODSIGN: Add -s <signature> option to sign-file MODSIGN: Specify the hash algorithm on sign-file command line MODSIGN: Simplify Makefile with a Kconfig helper module: clean up load_module a little more. modpost: Ignore ARC specific non-alloc sections module: constify within_module_* taint: add explicit flag to show whether lock dep is still OK. module: printk message when module signature fail taints kernel.
| * taint: add explicit flag to show whether lock dep is still OK.Rusty Russell2013-01-211-1/+1
| | | | | | | | | | | | | | Fix up all callers as they were before, with make one change: an unsigned module taints the kernel, but doesn't turn off lockdep. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | ACPI: fix obsolete comment in custom_method.cZhang Rui2013-01-261-1/+1
|/ | | | | | | | | The comment describing the contents of the custom_method.c file is obsolete, so update it. [rjw: Subject and changelog] Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* ACPI: Split out custom_method functionality into an own driverThomas Renninger2011-05-291-0/+100
With /sys/kernel/debug/acpi/custom_method root can write to arbitrary memory and increase his priveleges, even if these are restricted. -> Make this an own debug .config option and warn about the security issue in the config description. -> Still keep acpi/debugfs.c which now only creates an empty /sys/kernel/debug/acpi directory. There might be other users of it later. Signed-off-by: Thomas Renninger <trenn@suse.de> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: rui.zhang@intel.com Signed-off-by: Len Brown <len.brown@intel.com>