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security.c
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5679 lines (5240 loc) · 162 KB
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Security plug functions
*
* Copyright (C) 2001 WireX Communications, Inc <[email protected]>
* Copyright (C) 2001-2002 Greg Kroah-Hartman <[email protected]>
* Copyright (C) 2001 Networks Associates Technology, Inc <[email protected]>
* Copyright (C) 2016 Mellanox Technologies
* Copyright (C) 2023 Microsoft Corporation <[email protected]>
*/
#define pr_fmt(fmt) "LSM: " fmt
#include <linux/bpf.h>
#include <linux/capability.h>
#include <linux/dcache.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
#include <linux/lsm_hooks.h>
#include <linux/fsnotify.h>
#include <linux/mman.h>
#include <linux/mount.h>
#include <linux/personality.h>
#include <linux/backing-dev.h>
#include <linux/string.h>
#include <linux/xattr.h>
#include <linux/msg.h>
#include <linux/overflow.h>
#include <net/flow.h>
/* How many LSMs were built into the kernel? */
#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
/*
* How many LSMs are built into the kernel as determined at
* build time. Used to determine fixed array sizes.
* The capability module is accounted for by CONFIG_SECURITY
*/
#define LSM_CONFIG_COUNT ( \
(IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \
(IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \
(IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0) + \
(IS_ENABLED(CONFIG_IMA) ? 1 : 0) + \
(IS_ENABLED(CONFIG_EVM) ? 1 : 0))
/*
* These are descriptions of the reasons that can be passed to the
* security_locked_down() LSM hook. Placing this array here allows
* all security modules to use the same descriptions for auditing
* purposes.
*/
const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX + 1] = {
[LOCKDOWN_NONE] = "none",
[LOCKDOWN_MODULE_SIGNATURE] = "unsigned module loading",
[LOCKDOWN_DEV_MEM] = "/dev/mem,kmem,port",
[LOCKDOWN_EFI_TEST] = "/dev/efi_test access",
[LOCKDOWN_KEXEC] = "kexec of unsigned images",
[LOCKDOWN_HIBERNATION] = "hibernation",
[LOCKDOWN_PCI_ACCESS] = "direct PCI access",
[LOCKDOWN_IOPORT] = "raw io port access",
[LOCKDOWN_MSR] = "raw MSR access",
[LOCKDOWN_ACPI_TABLES] = "modifying ACPI tables",
[LOCKDOWN_DEVICE_TREE] = "modifying device tree contents",
[LOCKDOWN_PCMCIA_CIS] = "direct PCMCIA CIS storage",
[LOCKDOWN_TIOCSSERIAL] = "reconfiguration of serial port IO",
[LOCKDOWN_MODULE_PARAMETERS] = "unsafe module parameters",
[LOCKDOWN_MMIOTRACE] = "unsafe mmio",
[LOCKDOWN_DEBUGFS] = "debugfs access",
[LOCKDOWN_XMON_WR] = "xmon write access",
[LOCKDOWN_BPF_WRITE_USER] = "use of bpf to write user RAM",
[LOCKDOWN_DBG_WRITE_KERNEL] = "use of kgdb/kdb to write kernel RAM",
[LOCKDOWN_RTAS_ERROR_INJECTION] = "RTAS error injection",
[LOCKDOWN_INTEGRITY_MAX] = "integrity",
[LOCKDOWN_KCORE] = "/proc/kcore access",
[LOCKDOWN_KPROBES] = "use of kprobes",
[LOCKDOWN_BPF_READ_KERNEL] = "use of bpf to read kernel RAM",
[LOCKDOWN_DBG_READ_KERNEL] = "use of kgdb/kdb to read kernel RAM",
[LOCKDOWN_PERF] = "unsafe use of perf",
[LOCKDOWN_TRACEFS] = "use of tracefs",
[LOCKDOWN_XMON_RW] = "xmon read and write access",
[LOCKDOWN_XFRM_SECRET] = "xfrm SA secret",
[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
};
struct security_hook_heads security_hook_heads __ro_after_init;
static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain);
static struct kmem_cache *lsm_file_cache;
static struct kmem_cache *lsm_inode_cache;
char *lsm_names;
static struct lsm_blob_sizes blob_sizes __ro_after_init;
/* Boot-time LSM user choice */
static __initdata const char *chosen_lsm_order;
static __initdata const char *chosen_major_lsm;
static __initconst const char *const builtin_lsm_order = CONFIG_LSM;
/* Ordered list of LSMs to initialize. */
static __initdata struct lsm_info **ordered_lsms;
static __initdata struct lsm_info *exclusive;
static __initdata bool debug;
#define init_debug(...) \
do { \
if (debug) \
pr_info(__VA_ARGS__); \
} while (0)
static bool __init is_enabled(struct lsm_info *lsm)
{
if (!lsm->enabled)
return false;
return *lsm->enabled;
}
/* Mark an LSM's enabled flag. */
static int lsm_enabled_true __initdata = 1;
static int lsm_enabled_false __initdata = 0;
static void __init set_enabled(struct lsm_info *lsm, bool enabled)
{
/*
* When an LSM hasn't configured an enable variable, we can use
* a hard-coded location for storing the default enabled state.
*/
if (!lsm->enabled) {
if (enabled)
lsm->enabled = &lsm_enabled_true;
else
lsm->enabled = &lsm_enabled_false;
} else if (lsm->enabled == &lsm_enabled_true) {
if (!enabled)
lsm->enabled = &lsm_enabled_false;
} else if (lsm->enabled == &lsm_enabled_false) {
if (enabled)
lsm->enabled = &lsm_enabled_true;
} else {
*lsm->enabled = enabled;
}
}
/* Is an LSM already listed in the ordered LSMs list? */
static bool __init exists_ordered_lsm(struct lsm_info *lsm)
{
struct lsm_info **check;
for (check = ordered_lsms; *check; check++)
if (*check == lsm)
return true;
return false;
}
/* Append an LSM to the list of ordered LSMs to initialize. */
static int last_lsm __initdata;
static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from)
{
/* Ignore duplicate selections. */
if (exists_ordered_lsm(lsm))
return;
if (WARN(last_lsm == LSM_COUNT, "%s: out of LSM slots!?\n", from))
return;
/* Enable this LSM, if it is not already set. */
if (!lsm->enabled)
lsm->enabled = &lsm_enabled_true;
ordered_lsms[last_lsm++] = lsm;
init_debug("%s ordered: %s (%s)\n", from, lsm->name,
is_enabled(lsm) ? "enabled" : "disabled");
}
/* Is an LSM allowed to be initialized? */
static bool __init lsm_allowed(struct lsm_info *lsm)
{
/* Skip if the LSM is disabled. */
if (!is_enabled(lsm))
return false;
/* Not allowed if another exclusive LSM already initialized. */
if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && exclusive) {
init_debug("exclusive disabled: %s\n", lsm->name);
return false;
}
return true;
}
static void __init lsm_set_blob_size(int *need, int *lbs)
{
int offset;
if (*need <= 0)
return;
offset = ALIGN(*lbs, sizeof(void *));
*lbs = offset + *need;
*need = offset;
}
static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
{
if (!needed)
return;
lsm_set_blob_size(&needed->lbs_cred, &blob_sizes.lbs_cred);
lsm_set_blob_size(&needed->lbs_file, &blob_sizes.lbs_file);
/*
* The inode blob gets an rcu_head in addition to
* what the modules might need.
*/
if (needed->lbs_inode && blob_sizes.lbs_inode == 0)
blob_sizes.lbs_inode = sizeof(struct rcu_head);
lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc);
lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock);
lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
lsm_set_blob_size(&needed->lbs_xattr_count,
&blob_sizes.lbs_xattr_count);
}
/* Prepare LSM for initialization. */
static void __init prepare_lsm(struct lsm_info *lsm)
{
int enabled = lsm_allowed(lsm);
/* Record enablement (to handle any following exclusive LSMs). */
set_enabled(lsm, enabled);
/* If enabled, do pre-initialization work. */
if (enabled) {
if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && !exclusive) {
exclusive = lsm;
init_debug("exclusive chosen: %s\n", lsm->name);
}
lsm_set_blob_sizes(lsm->blobs);
}
}
/* Initialize a given LSM, if it is enabled. */
static void __init initialize_lsm(struct lsm_info *lsm)
{
if (is_enabled(lsm)) {
int ret;
init_debug("initializing %s\n", lsm->name);
ret = lsm->init();
WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret);
}
}
/*
* Current index to use while initializing the lsm id list.
*/
u32 lsm_active_cnt __ro_after_init;
const struct lsm_id *lsm_idlist[LSM_CONFIG_COUNT];
/* Populate ordered LSMs list from comma-separated LSM name list. */
static void __init ordered_lsm_parse(const char *order, const char *origin)
{
struct lsm_info *lsm;
char *sep, *name, *next;
/* LSM_ORDER_FIRST is always first. */
for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
if (lsm->order == LSM_ORDER_FIRST)
append_ordered_lsm(lsm, " first");
}
/* Process "security=", if given. */
if (chosen_major_lsm) {
struct lsm_info *major;
/*
* To match the original "security=" behavior, this
* explicitly does NOT fallback to another Legacy Major
* if the selected one was separately disabled: disable
* all non-matching Legacy Major LSMs.
*/
for (major = __start_lsm_info; major < __end_lsm_info;
major++) {
if ((major->flags & LSM_FLAG_LEGACY_MAJOR) &&
strcmp(major->name, chosen_major_lsm) != 0) {
set_enabled(major, false);
init_debug("security=%s disabled: %s (only one legacy major LSM)\n",
chosen_major_lsm, major->name);
}
}
}
sep = kstrdup(order, GFP_KERNEL);
next = sep;
/* Walk the list, looking for matching LSMs. */
while ((name = strsep(&next, ",")) != NULL) {
bool found = false;
for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
if (strcmp(lsm->name, name) == 0) {
if (lsm->order == LSM_ORDER_MUTABLE)
append_ordered_lsm(lsm, origin);
found = true;
}
}
if (!found)
init_debug("%s ignored: %s (not built into kernel)\n",
origin, name);
}
/* Process "security=", if given. */
if (chosen_major_lsm) {
for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
if (exists_ordered_lsm(lsm))
continue;
if (strcmp(lsm->name, chosen_major_lsm) == 0)
append_ordered_lsm(lsm, "security=");
}
}
/* LSM_ORDER_LAST is always last. */
for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
if (lsm->order == LSM_ORDER_LAST)
append_ordered_lsm(lsm, " last");
}
/* Disable all LSMs not in the ordered list. */
for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
if (exists_ordered_lsm(lsm))
continue;
set_enabled(lsm, false);
init_debug("%s skipped: %s (not in requested order)\n",
origin, lsm->name);
}
kfree(sep);
}
static void __init lsm_early_cred(struct cred *cred);
static void __init lsm_early_task(struct task_struct *task);
static int lsm_append(const char *new, char **result);
static void __init report_lsm_order(void)
{
struct lsm_info **lsm, *early;
int first = 0;
pr_info("initializing lsm=");
/* Report each enabled LSM name, comma separated. */
for (early = __start_early_lsm_info;
early < __end_early_lsm_info; early++)
if (is_enabled(early))
pr_cont("%s%s", first++ == 0 ? "" : ",", early->name);
for (lsm = ordered_lsms; *lsm; lsm++)
if (is_enabled(*lsm))
pr_cont("%s%s", first++ == 0 ? "" : ",", (*lsm)->name);
pr_cont("\n");
}
static void __init ordered_lsm_init(void)
{
struct lsm_info **lsm;
ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),
GFP_KERNEL);
if (chosen_lsm_order) {
if (chosen_major_lsm) {
pr_warn("security=%s is ignored because it is superseded by lsm=%s\n",
chosen_major_lsm, chosen_lsm_order);
chosen_major_lsm = NULL;
}
ordered_lsm_parse(chosen_lsm_order, "cmdline");
} else
ordered_lsm_parse(builtin_lsm_order, "builtin");
for (lsm = ordered_lsms; *lsm; lsm++)
prepare_lsm(*lsm);
report_lsm_order();
init_debug("cred blob size = %d\n", blob_sizes.lbs_cred);
init_debug("file blob size = %d\n", blob_sizes.lbs_file);
init_debug("inode blob size = %d\n", blob_sizes.lbs_inode);
init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc);
init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
init_debug("task blob size = %d\n", blob_sizes.lbs_task);
init_debug("xattr slots = %d\n", blob_sizes.lbs_xattr_count);
/*
* Create any kmem_caches needed for blobs
*/
if (blob_sizes.lbs_file)
lsm_file_cache = kmem_cache_create("lsm_file_cache",
blob_sizes.lbs_file, 0,
SLAB_PANIC, NULL);
if (blob_sizes.lbs_inode)
lsm_inode_cache = kmem_cache_create("lsm_inode_cache",
blob_sizes.lbs_inode, 0,
SLAB_PANIC, NULL);
lsm_early_cred((struct cred *) current->cred);
lsm_early_task(current);
for (lsm = ordered_lsms; *lsm; lsm++)
initialize_lsm(*lsm);
kfree(ordered_lsms);
}
int __init early_security_init(void)
{
struct lsm_info *lsm;
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
INIT_HLIST_HEAD(&security_hook_heads.NAME);
#include "linux/lsm_hook_defs.h"
#undef LSM_HOOK
for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) {
if (!lsm->enabled)
lsm->enabled = &lsm_enabled_true;
prepare_lsm(lsm);
initialize_lsm(lsm);
}
return 0;
}
/**
* security_init - initializes the security framework
*
* This should be called early in the kernel initialization sequence.
*/
int __init security_init(void)
{
struct lsm_info *lsm;
init_debug("legacy security=%s\n", chosen_major_lsm ? : " *unspecified*");
init_debug(" CONFIG_LSM=%s\n", builtin_lsm_order);
init_debug("boot arg lsm=%s\n", chosen_lsm_order ? : " *unspecified*");
/*
* Append the names of the early LSM modules now that kmalloc() is
* available
*/
for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) {
init_debug(" early started: %s (%s)\n", lsm->name,
is_enabled(lsm) ? "enabled" : "disabled");
if (lsm->enabled)
lsm_append(lsm->name, &lsm_names);
}
/* Load LSMs in specified order. */
ordered_lsm_init();
return 0;
}
/* Save user chosen LSM */
static int __init choose_major_lsm(char *str)
{
chosen_major_lsm = str;
return 1;
}
__setup("security=", choose_major_lsm);
/* Explicitly choose LSM initialization order. */
static int __init choose_lsm_order(char *str)
{
chosen_lsm_order = str;
return 1;
}
__setup("lsm=", choose_lsm_order);
/* Enable LSM order debugging. */
static int __init enable_debug(char *str)
{
debug = true;
return 1;
}
__setup("lsm.debug", enable_debug);
static bool match_last_lsm(const char *list, const char *lsm)
{
const char *last;
if (WARN_ON(!list || !lsm))
return false;
last = strrchr(list, ',');
if (last)
/* Pass the comma, strcmp() will check for '\0' */
last++;
else
last = list;
return !strcmp(last, lsm);
}
static int lsm_append(const char *new, char **result)
{
char *cp;
if (*result == NULL) {
*result = kstrdup(new, GFP_KERNEL);
if (*result == NULL)
return -ENOMEM;
} else {
/* Check if it is the last registered name */
if (match_last_lsm(*result, new))
return 0;
cp = kasprintf(GFP_KERNEL, "%s,%s", *result, new);
if (cp == NULL)
return -ENOMEM;
kfree(*result);
*result = cp;
}
return 0;
}
/**
* security_add_hooks - Add a modules hooks to the hook lists.
* @hooks: the hooks to add
* @count: the number of hooks to add
* @lsmid: the identification information for the security module
*
* Each LSM has to register its hooks with the infrastructure.
*/
void __init security_add_hooks(struct security_hook_list *hooks, int count,
const struct lsm_id *lsmid)
{
int i;
/*
* A security module may call security_add_hooks() more
* than once during initialization, and LSM initialization
* is serialized. Landlock is one such case.
* Look at the previous entry, if there is one, for duplication.
*/
if (lsm_active_cnt == 0 || lsm_idlist[lsm_active_cnt - 1] != lsmid) {
if (lsm_active_cnt >= LSM_CONFIG_COUNT)
panic("%s Too many LSMs registered.\n", __func__);
lsm_idlist[lsm_active_cnt++] = lsmid;
}
for (i = 0; i < count; i++) {
hooks[i].lsmid = lsmid;
hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
}
/*
* 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(lsmid->name, &lsm_names) < 0)
panic("%s - Cannot get early memory.\n", __func__);
}
}
int call_blocking_lsm_notifier(enum lsm_event event, void *data)
{
return blocking_notifier_call_chain(&blocking_lsm_notifier_chain,
event, data);
}
EXPORT_SYMBOL(call_blocking_lsm_notifier);
int register_blocking_lsm_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&blocking_lsm_notifier_chain,
nb);
}
EXPORT_SYMBOL(register_blocking_lsm_notifier);
int unregister_blocking_lsm_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&blocking_lsm_notifier_chain,
nb);
}
EXPORT_SYMBOL(unregister_blocking_lsm_notifier);
/**
* lsm_cred_alloc - allocate a composite cred blob
* @cred: the cred that needs a blob
* @gfp: allocation type
*
* Allocate the cred blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
static int lsm_cred_alloc(struct cred *cred, gfp_t gfp)
{
if (blob_sizes.lbs_cred == 0) {
cred->security = NULL;
return 0;
}
cred->security = kzalloc(blob_sizes.lbs_cred, gfp);
if (cred->security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_early_cred - during initialization allocate a composite cred blob
* @cred: the cred that needs a blob
*
* Allocate the cred blob for all the modules
*/
static void __init lsm_early_cred(struct cred *cred)
{
int rc = lsm_cred_alloc(cred, GFP_KERNEL);
if (rc)
panic("%s: Early cred alloc failed.\n", __func__);
}
/**
* lsm_file_alloc - allocate a composite file blob
* @file: the file that needs a blob
*
* Allocate the file blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
static int lsm_file_alloc(struct file *file)
{
if (!lsm_file_cache) {
file->f_security = NULL;
return 0;
}
file->f_security = kmem_cache_zalloc(lsm_file_cache, GFP_KERNEL);
if (file->f_security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_inode_alloc - allocate a composite inode blob
* @inode: the inode that needs a blob
*
* Allocate the inode blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
int lsm_inode_alloc(struct inode *inode)
{
if (!lsm_inode_cache) {
inode->i_security = NULL;
return 0;
}
inode->i_security = kmem_cache_zalloc(lsm_inode_cache, GFP_NOFS);
if (inode->i_security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_task_alloc - allocate a composite task blob
* @task: the task that needs a blob
*
* Allocate the task blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
static int lsm_task_alloc(struct task_struct *task)
{
if (blob_sizes.lbs_task == 0) {
task->security = NULL;
return 0;
}
task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
if (task->security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_ipc_alloc - allocate a composite ipc blob
* @kip: the ipc that needs a blob
*
* Allocate the ipc blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
static int lsm_ipc_alloc(struct kern_ipc_perm *kip)
{
if (blob_sizes.lbs_ipc == 0) {
kip->security = NULL;
return 0;
}
kip->security = kzalloc(blob_sizes.lbs_ipc, GFP_KERNEL);
if (kip->security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_msg_msg_alloc - allocate a composite msg_msg blob
* @mp: the msg_msg that needs a blob
*
* Allocate the ipc blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
static int lsm_msg_msg_alloc(struct msg_msg *mp)
{
if (blob_sizes.lbs_msg_msg == 0) {
mp->security = NULL;
return 0;
}
mp->security = kzalloc(blob_sizes.lbs_msg_msg, GFP_KERNEL);
if (mp->security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_early_task - during initialization allocate a composite task blob
* @task: the task that needs a blob
*
* Allocate the task blob for all the modules
*/
static void __init lsm_early_task(struct task_struct *task)
{
int rc = lsm_task_alloc(task);
if (rc)
panic("%s: Early task alloc failed.\n", __func__);
}
/**
* lsm_superblock_alloc - allocate a composite superblock blob
* @sb: the superblock that needs a blob
*
* Allocate the superblock blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
static int lsm_superblock_alloc(struct super_block *sb)
{
if (blob_sizes.lbs_superblock == 0) {
sb->s_security = NULL;
return 0;
}
sb->s_security = kzalloc(blob_sizes.lbs_superblock, GFP_KERNEL);
if (sb->s_security == NULL)
return -ENOMEM;
return 0;
}
/**
* lsm_fill_user_ctx - Fill a user space lsm_ctx structure
* @uctx: a userspace LSM context to be filled
* @uctx_len: available uctx size (input), used uctx size (output)
* @val: the new LSM context value
* @val_len: the size of the new LSM context value
* @id: LSM id
* @flags: LSM defined flags
*
* Fill all of the fields in a userspace lsm_ctx structure. If @uctx is NULL
* simply calculate the required size to output via @utc_len and return
* success.
*
* Returns 0 on success, -E2BIG if userspace buffer is not large enough,
* -EFAULT on a copyout error, -ENOMEM if memory can't be allocated.
*/
int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len,
void *val, size_t val_len,
u64 id, u64 flags)
{
struct lsm_ctx *nctx = NULL;
size_t nctx_len;
int rc = 0;
nctx_len = ALIGN(struct_size(nctx, ctx, val_len), sizeof(void *));
if (nctx_len > *uctx_len) {
rc = -E2BIG;
goto out;
}
/* no buffer - return success/0 and set @uctx_len to the req size */
if (!uctx)
goto out;
nctx = kzalloc(nctx_len, GFP_KERNEL);
if (nctx == NULL) {
rc = -ENOMEM;
goto out;
}
nctx->id = id;
nctx->flags = flags;
nctx->len = nctx_len;
nctx->ctx_len = val_len;
memcpy(nctx->ctx, val, val_len);
if (copy_to_user(uctx, nctx, nctx_len))
rc = -EFAULT;
out:
kfree(nctx);
*uctx_len = nctx_len;
return rc;
}
/*
* The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
* can be accessed with:
*
* LSM_RET_DEFAULT(<hook_name>)
*
* The macros below define static constants for the default value of each
* LSM hook.
*/
#define LSM_RET_DEFAULT(NAME) (NAME##_default)
#define DECLARE_LSM_RET_DEFAULT_void(DEFAULT, NAME)
#define DECLARE_LSM_RET_DEFAULT_int(DEFAULT, NAME) \
static const int __maybe_unused LSM_RET_DEFAULT(NAME) = (DEFAULT);
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
DECLARE_LSM_RET_DEFAULT_##RET(DEFAULT, NAME)
#include <linux/lsm_hook_defs.h>
#undef LSM_HOOK
/*
* Hook list operation macros.
*
* call_void_hook:
* This is a hook that does not return a value.
*
* call_int_hook:
* This is a hook that returns a value.
*/
#define call_void_hook(FUNC, ...) \
do { \
struct security_hook_list *P; \
\
hlist_for_each_entry(P, &security_hook_heads.FUNC, list) \
P->hook.FUNC(__VA_ARGS__); \
} while (0)
#define call_int_hook(FUNC, ...) ({ \
int RC = LSM_RET_DEFAULT(FUNC); \
do { \
struct security_hook_list *P; \
\
hlist_for_each_entry(P, &security_hook_heads.FUNC, list) { \
RC = P->hook.FUNC(__VA_ARGS__); \
if (RC != LSM_RET_DEFAULT(FUNC)) \
break; \
} \
} while (0); \
RC; \
})
/* Security operations */
/**
* security_binder_set_context_mgr() - Check if becoming binder ctx mgr is ok
* @mgr: task credentials of current binder process
*
* Check whether @mgr is allowed to be the binder context manager.
*
* Return: Return 0 if permission is granted.
*/
int security_binder_set_context_mgr(const struct cred *mgr)
{
return call_int_hook(binder_set_context_mgr, mgr);
}
/**
* security_binder_transaction() - Check if a binder transaction is allowed
* @from: sending process
* @to: receiving process
*
* Check whether @from is allowed to invoke a binder transaction call to @to.
*
* Return: Returns 0 if permission is granted.
*/
int security_binder_transaction(const struct cred *from,
const struct cred *to)
{
return call_int_hook(binder_transaction, from, to);
}
/**
* security_binder_transfer_binder() - Check if a binder transfer is allowed
* @from: sending process
* @to: receiving process
*
* Check whether @from is allowed to transfer a binder reference to @to.
*
* Return: Returns 0 if permission is granted.
*/
int security_binder_transfer_binder(const struct cred *from,
const struct cred *to)
{
return call_int_hook(binder_transfer_binder, from, to);
}
/**
* security_binder_transfer_file() - Check if a binder file xfer is allowed
* @from: sending process
* @to: receiving process
* @file: file being transferred
*
* Check whether @from is allowed to transfer @file to @to.
*
* Return: Returns 0 if permission is granted.
*/
int security_binder_transfer_file(const struct cred *from,
const struct cred *to, const struct file *file)
{
return call_int_hook(binder_transfer_file, from, to, file);
}
/**
* security_ptrace_access_check() - Check if tracing is allowed
* @child: target process
* @mode: PTRACE_MODE flags
*
* Check permission before allowing the current process to trace the @child
* process. Security modules may also want to perform a process tracing check
* during an execve in the set_security or apply_creds hooks of tracing check
* during an execve in the bprm_set_creds hook of binprm_security_ops if the
* process is being traced and its security attributes would be changed by the
* execve.
*
* Return: Returns 0 if permission is granted.
*/
int security_ptrace_access_check(struct task_struct *child, unsigned int mode)
{
return call_int_hook(ptrace_access_check, child, mode);
}
/**
* security_ptrace_traceme() - Check if tracing is allowed
* @parent: tracing process
*
* Check that the @parent process has sufficient permission to trace the
* current process before allowing the current process to present itself to the
* @parent process for tracing.
*
* Return: Returns 0 if permission is granted.
*/
int security_ptrace_traceme(struct task_struct *parent)
{
return call_int_hook(ptrace_traceme, parent);
}
/**
* security_capget() - Get the capability sets for a process
* @target: target process
* @effective: effective capability set
* @inheritable: inheritable capability set
* @permitted: permitted capability set
*
* Get the @effective, @inheritable, and @permitted capability sets for the
* @target process. The hook may also perform permission checking to determine
* if the current process is allowed to see the capability sets of the @target
* process.
*
* Return: Returns 0 if the capability sets were successfully obtained.
*/
int security_capget(const struct task_struct *target,
kernel_cap_t *effective,
kernel_cap_t *inheritable,
kernel_cap_t *permitted)
{
return call_int_hook(capget, target, effective, inheritable, permitted);
}
/**
* security_capset() - Set the capability sets for a process
* @new: new credentials for the target process
* @old: current credentials of the target process
* @effective: effective capability set