mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-19 00:55:18 +00:00
aefcf2f4b5
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 9d1f8be5cf ("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
...
143 lines
3.4 KiB
C
143 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2008 IBM Corporation
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* Author: Mimi Zohar <zohar@us.ibm.com>
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*/
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#ifndef _LINUX_IMA_H
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#define _LINUX_IMA_H
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#include <linux/fs.h>
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#include <linux/security.h>
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#include <linux/kexec.h>
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struct linux_binprm;
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#ifdef CONFIG_IMA
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extern int ima_bprm_check(struct linux_binprm *bprm);
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extern int ima_file_check(struct file *file, int mask);
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extern void ima_post_create_tmpfile(struct inode *inode);
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extern void ima_file_free(struct file *file);
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extern int ima_file_mmap(struct file *file, unsigned long prot);
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extern int ima_load_data(enum kernel_load_data_id id);
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extern int ima_read_file(struct file *file, enum kernel_read_file_id id);
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extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
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enum kernel_read_file_id id);
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extern void ima_post_path_mknod(struct dentry *dentry);
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extern void ima_kexec_cmdline(const void *buf, int size);
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#ifdef CONFIG_IMA_KEXEC
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extern void ima_add_kexec_buffer(struct kimage *image);
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#endif
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#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390)
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extern bool arch_ima_get_secureboot(void);
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extern const char * const *arch_get_ima_policy(void);
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#else
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static inline bool arch_ima_get_secureboot(void)
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{
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return false;
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}
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static inline const char * const *arch_get_ima_policy(void)
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{
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return NULL;
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}
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#endif
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#else
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static inline int ima_bprm_check(struct linux_binprm *bprm)
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{
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return 0;
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}
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static inline int ima_file_check(struct file *file, int mask)
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{
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return 0;
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}
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static inline void ima_post_create_tmpfile(struct inode *inode)
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{
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}
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static inline void ima_file_free(struct file *file)
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{
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return;
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}
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static inline int ima_file_mmap(struct file *file, unsigned long prot)
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{
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return 0;
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}
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static inline int ima_load_data(enum kernel_load_data_id id)
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{
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return 0;
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}
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static inline int ima_read_file(struct file *file, enum kernel_read_file_id id)
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{
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return 0;
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}
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static inline int ima_post_read_file(struct file *file, void *buf, loff_t size,
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enum kernel_read_file_id id)
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{
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return 0;
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}
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static inline void ima_post_path_mknod(struct dentry *dentry)
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{
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return;
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}
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static inline void ima_kexec_cmdline(const void *buf, int size) {}
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#endif /* CONFIG_IMA */
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#ifndef CONFIG_IMA_KEXEC
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struct kimage;
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static inline void ima_add_kexec_buffer(struct kimage *image)
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{}
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#endif
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#ifdef CONFIG_IMA_APPRAISE
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extern bool is_ima_appraise_enabled(void);
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extern void ima_inode_post_setattr(struct dentry *dentry);
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extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
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const void *xattr_value, size_t xattr_value_len);
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extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name);
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#else
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static inline bool is_ima_appraise_enabled(void)
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{
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return 0;
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}
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static inline void ima_inode_post_setattr(struct dentry *dentry)
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{
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return;
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}
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static inline int ima_inode_setxattr(struct dentry *dentry,
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const char *xattr_name,
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const void *xattr_value,
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size_t xattr_value_len)
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{
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return 0;
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}
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static inline int ima_inode_removexattr(struct dentry *dentry,
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const char *xattr_name)
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{
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return 0;
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}
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#endif /* CONFIG_IMA_APPRAISE */
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#if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
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extern bool ima_appraise_signature(enum kernel_read_file_id func);
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#else
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static inline bool ima_appraise_signature(enum kernel_read_file_id func)
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{
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return false;
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}
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#endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
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#endif /* _LINUX_IMA_H */
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