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
cba9ff5837f1 ("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
...
def_bool y
depends on KEXEC_FILE
- config KEXEC_VERIFY_SIG
+ config KEXEC_SIG
bool "Verify kernel signature during kexec_file_load() syscall"
- depends on KEXEC_FILE && SYSTEM_DATA_VERIFICATION
+ depends on KEXEC_FILE && MODULE_SIG_FORMAT
help
This option makes kernel signature verification mandatory for
the kexec_file_load() syscall.
NULL,
};
- #ifdef CONFIG_KEXEC_VERIFY_SIG
+ #ifdef CONFIG_KEXEC_SIG
-/*
- * Module signature information block.
- *
- * The constituents of the signature section are, in order:
- *
- * - Signer's name
- * - Key identifier
- * - Signature data
- * - Information block
- */
-struct module_signature {
- u8 algo; /* Public-key crypto algorithm [0] */
- u8 hash; /* Digest algorithm [0] */
- u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */
- u8 signer_len; /* Length of signer's name [0] */
- u8 key_id_len; /* Length of key identifier [0] */
- u8 __pad[3];
- __be32 sig_len; /* Length of signature data */
-};
-
-#define PKEY_ID_PKCS7 2
-
int s390_verify_sig(const char *kernel, unsigned long kernel_len)
{
const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;
{
acpi_physical_address pa;
- pa = get_acpi_rsdp();
-
- if (!pa)
- pa = boot_params->acpi_rsdp_addr;
+ pa = boot_params->acpi_rsdp_addr;
+ /*
+ * Try to get EFI data from setup_data. This can happen when we're a
+ * kexec'ed kernel and kexec(1) has passed all the required EFI info to
+ * us.
+ */
+ if (!pa)
+ pa = kexec_get_rsdp_addr();
+
if (!pa)
pa = efi_get_rsdp_addr();
return dentry;
inode = debugfs_get_inode(dentry->d_sb);
- if (unlikely(!inode))
+ if (unlikely(!inode)) {
+ pr_err("out of free dentries, can not create directory '%s'\n",
+ name);
return failed_creating(dentry);
+ }
inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
- inode->i_op = &simple_dir_inode_operations;
+ inode->i_op = &debugfs_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
/* directory inodes start off with i_nlink == 2 (for "." entry) */
IRQCHIP_OF_MATCH_TABLE() \
ACPI_PROBE_TABLE(irqchip) \
ACPI_PROBE_TABLE(timer) \
+ THERMAL_TABLE(governor) \
EARLYCON_TABLE() \
- LSM_TABLE()
+ LSM_TABLE() \
+ EARLY_LSM_TABLE()
#define INIT_TEXT \
*(.init.text .init.text.*) \
int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+ int security_locked_down(enum lockdown_reason what);
#else /* CONFIG_SECURITY */
-static inline int call_lsm_notifier(enum lsm_event event, void *data)
+static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
{
return 0;
}
boot_cpu_init();
page_address_init();
pr_notice("%s", linux_banner);
+ early_security_init();
setup_arch(&command_line);
- mm_init_cpumask(&init_mm);
setup_command_line(command_line);
setup_nr_cpu_ids();
setup_per_cpu_areas();
#include <linux/uaccess.h>
#include <linux/rculist.h>
#include <linux/error-injection.h>
+ #include <linux/security.h>
+#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
+
#include "trace_dynevent.h"
#include "trace_kprobe_selftest.h"
#include "trace_probe.h"
{
int i, ret;
- if (trace_probe_is_registered(&tk->tp))
+ ret = security_locked_down(LOCKDOWN_KPROBES);
+ if (ret)
+ return ret;
+
+ if (trace_kprobe_is_registered(tk))
return -EINVAL;
if (within_notrace_func(tk)) {
config IMA_ARCH_POLICY
bool "Enable loading an IMA architecture specific policy"
- depends on (KEXEC_VERIFY_SIG && IMA) || IMA_APPRAISE \
- depends on KEXEC_SIG || IMA_APPRAISE && INTEGRITY_ASYMMETRIC_KEYS
++ depends on (KEXEC_SIG && IMA) || IMA_APPRAISE \
+ && INTEGRITY_ASYMMETRIC_KEYS
default n
help
This option enables loading an IMA architecture specific policy
/* How many LSMs were built into the kernel? */
#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
+ #define EARLY_LSM_COUNT (__end_early_lsm_info - __start_early_lsm_info)
struct security_hook_heads security_hook_heads __lsm_ro_after_init;
-static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
+static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain);
static struct kmem_cache *lsm_file_cache;
static struct kmem_cache *lsm_inode_cache;
hooks[i].lsm = lsm;
hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
}
- if (lsm_append(lsm, &lsm_names) < 0)
- panic("%s - Cannot get early memory.\n", __func__);
+
+ /*
+ * Don't try to append during early_security_init(), we'll come back
+ * and fix this up afterwards.
+ */
+ if (slab_is_available()) {
+ if (lsm_append(lsm, &lsm_names) < 0)
+ panic("%s - Cannot get early memory.\n", __func__);
+ }
}
-int call_lsm_notifier(enum lsm_event event, void *data)
+int call_blocking_lsm_notifier(enum lsm_event event, void *data)
{
- return atomic_notifier_call_chain(&lsm_notifier_chain, event, data);
+ return blocking_notifier_call_chain(&blocking_lsm_notifier_chain,
+ event, data);
}
-EXPORT_SYMBOL(call_lsm_notifier);
+EXPORT_SYMBOL(call_blocking_lsm_notifier);
-int register_lsm_notifier(struct notifier_block *nb)
+int register_blocking_lsm_notifier(struct notifier_block *nb)
{
- return atomic_notifier_chain_register(&lsm_notifier_chain, nb);
+ return blocking_notifier_chain_register(&blocking_lsm_notifier_chain,
+ nb);
}
-EXPORT_SYMBOL(register_lsm_notifier);
+EXPORT_SYMBOL(register_blocking_lsm_notifier);
-int unregister_lsm_notifier(struct notifier_block *nb)
+int unregister_blocking_lsm_notifier(struct notifier_block *nb)
{
- return atomic_notifier_chain_unregister(&lsm_notifier_chain, nb);
+ return blocking_notifier_chain_unregister(&blocking_lsm_notifier_chain,
+ nb);
}
-EXPORT_SYMBOL(unregister_lsm_notifier);
+EXPORT_SYMBOL(unregister_blocking_lsm_notifier);
/**
* lsm_cred_alloc - allocate a composite cred blob
projects / kernel.git / commitdiff