Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
kernel-fxtec-pro1x/kernel/cred.c
David Howells ee18d64c1f KEYS: Add a keyctl to install a process's session keyring on its parent [try #6] 
Add a keyctl to install a process's session keyring onto its parent.  This
replaces the parent's session keyring.  Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again.  Normally this
will be after a wait*() syscall.

To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.

The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.

Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME.  This allows the
replacement to be performed at the point the parent process resumes userspace
execution.

This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership.  However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.

This can be tested with the following program:

	#include <stdio.h>
	#include <stdlib.h>
	#include <keyutils.h>

	#define KEYCTL_SESSION_TO_PARENT	18

	#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)

	int main(int argc, char **argv)
	{
		key_serial_t keyring, key;
		long ret;

		keyring = keyctl_join_session_keyring(argv[1]);
		OSERROR(keyring, "keyctl_join_session_keyring");

		key = add_key("user", "a", "b", 1, keyring);
		OSERROR(key, "add_key");

		ret = keyctl(KEYCTL_SESSION_TO_PARENT);
		OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");

		return 0;
	}

Compiled and linked with -lkeyutils, you should see something like:

	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	355907932 --alswrv   4043    -1   \_ keyring: _uid.4043
	[dhowells@andromeda ~]$ /tmp/newpag
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	1055658746 --alswrv   4043  4043   \_ user: a
	[dhowells@andromeda ~]$ /tmp/newpag hello
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: hello
	340417692 --alswrv   4043  4043   \_ user: a

Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 21:29:22 +10:00

872 lines
22 KiB
C
Raw Blame History

/* Task credentials management - see Documentation/credentials.txt
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/cred.h>
#include <linux/sched.h>
#include <linux/key.h>
#include <linux/keyctl.h>
#include <linux/init_task.h>
#include <linux/security.h>
#include <linux/cn_proc.h>
#include "cred-internals.h"
#if 0
#define kdebug(FMT, ...) \
printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__)
#else
static inline __attribute__((format(printf, 1, 2)))
void no_printk(const char *fmt, ...)
{
}
#define kdebug(FMT, ...) \
no_printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__)
#endif
static struct kmem_cache *cred_jar;
/*
* The common credentials for the initial task's thread group
*/
#ifdef CONFIG_KEYS
static struct thread_group_cred init_tgcred = {
.usage = ATOMIC_INIT(2),
.tgid = 0,
.lock = SPIN_LOCK_UNLOCKED,
};
#endif
/*
* The initial credentials for the initial task
*/
struct cred init_cred = {
.usage = ATOMIC_INIT(4),
#ifdef CONFIG_DEBUG_CREDENTIALS
.subscribers = ATOMIC_INIT(2),
.magic = CRED_MAGIC,
#endif
.securebits = SECUREBITS_DEFAULT,
.cap_inheritable = CAP_INIT_INH_SET,
.cap_permitted = CAP_FULL_SET,
.cap_effective = CAP_INIT_EFF_SET,
.cap_bset = CAP_INIT_BSET,
.user = INIT_USER,
.group_info = &init_groups,
#ifdef CONFIG_KEYS
.tgcred = &init_tgcred,
#endif
};
static inline void set_cred_subscribers(struct cred *cred, int n)
{
#ifdef CONFIG_DEBUG_CREDENTIALS
atomic_set(&cred->subscribers, n);
#endif
}
static inline int read_cred_subscribers(const struct cred *cred)
{
#ifdef CONFIG_DEBUG_CREDENTIALS
return atomic_read(&cred->subscribers);
#else
return 0;
#endif
}
static inline void alter_cred_subscribers(const struct cred *_cred, int n)
{
#ifdef CONFIG_DEBUG_CREDENTIALS
struct cred *cred = (struct cred *) _cred;
atomic_add(n, &cred->subscribers);
#endif
}
/*
* Dispose of the shared task group credentials
*/
#ifdef CONFIG_KEYS
static void release_tgcred_rcu(struct rcu_head *rcu)
{
struct thread_group_cred *tgcred =
container_of(rcu, struct thread_group_cred, rcu);
BUG_ON(atomic_read(&tgcred->usage) != 0);
key_put(tgcred->session_keyring);
key_put(tgcred->process_keyring);
kfree(tgcred);
}
#endif
/*
* Release a set of thread group credentials.
*/
static void release_tgcred(struct cred *cred)
{
#ifdef CONFIG_KEYS
struct thread_group_cred *tgcred = cred->tgcred;
if (atomic_dec_and_test(&tgcred->usage))
call_rcu(&tgcred->rcu, release_tgcred_rcu);
#endif
}
/*
* The RCU callback to actually dispose of a set of credentials
*/
static void put_cred_rcu(struct rcu_head *rcu)
{
struct cred *cred = container_of(rcu, struct cred, rcu);
kdebug("put_cred_rcu(%p)", cred);
#ifdef CONFIG_DEBUG_CREDENTIALS
if (cred->magic != CRED_MAGIC_DEAD ||
atomic_read(&cred->usage) != 0 ||
read_cred_subscribers(cred) != 0)
panic("CRED: put_cred_rcu() sees %p with"
" mag %x, put %p, usage %d, subscr %d\n",
cred, cred->magic, cred->put_addr,
atomic_read(&cred->usage),
read_cred_subscribers(cred));
#else
if (atomic_read(&cred->usage) != 0)
panic("CRED: put_cred_rcu() sees %p with usage %d\n",
cred, atomic_read(&cred->usage));
#endif
security_cred_free(cred);
key_put(cred->thread_keyring);
key_put(cred->request_key_auth);
release_tgcred(cred);
put_group_info(cred->group_info);
free_uid(cred->user);
kmem_cache_free(cred_jar, cred);
}
/**
* __put_cred - Destroy a set of credentials
* @cred: The record to release
*
* Destroy a set of credentials on which no references remain.
*/
void __put_cred(struct cred *cred)
{
kdebug("__put_cred(%p{%d,%d})", cred,
atomic_read(&cred->usage),
read_cred_subscribers(cred));
BUG_ON(atomic_read(&cred->usage) != 0);
#ifdef CONFIG_DEBUG_CREDENTIALS
BUG_ON(read_cred_subscribers(cred) != 0);
cred->magic = CRED_MAGIC_DEAD;
cred->put_addr = __builtin_return_address(0);
#endif
BUG_ON(cred == current->cred);
BUG_ON(cred == current->real_cred);
call_rcu(&cred->rcu, put_cred_rcu);
}
EXPORT_SYMBOL(__put_cred);
/*
* Clean up a task's credentials when it exits
*/
void exit_creds(struct task_struct *tsk)
{
struct cred *cred;
kdebug("exit_creds(%u,%p,%p,{%d,%d})", tsk->pid, tsk->real_cred, tsk->cred,
atomic_read(&tsk->cred->usage),
read_cred_subscribers(tsk->cred));
cred = (struct cred *) tsk->real_cred;
tsk->real_cred = NULL;
validate_creds(cred);
alter_cred_subscribers(cred, -1);
put_cred(cred);
cred = (struct cred *) tsk->cred;
tsk->cred = NULL;
validate_creds(cred);
alter_cred_subscribers(cred, -1);
put_cred(cred);
cred = (struct cred *) tsk->replacement_session_keyring;
if (cred) {
tsk->replacement_session_keyring = NULL;
validate_creds(cred);
put_cred(cred);
}
}
/*
* Allocate blank credentials, such that the credentials can be filled in at a
* later date without risk of ENOMEM.
*/
struct cred *cred_alloc_blank(void)
{
struct cred *new;
new = kmem_cache_zalloc(cred_jar, GFP_KERNEL);
if (!new)
return NULL;
#ifdef CONFIG_KEYS
new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL);
if (!new->tgcred) {
kfree(new);
return NULL;
}
atomic_set(&new->tgcred->usage, 1);
#endif
atomic_set(&new->usage, 1);
if (security_cred_alloc_blank(new, GFP_KERNEL) < 0)
goto error;
#ifdef CONFIG_DEBUG_CREDENTIALS
new->magic = CRED_MAGIC;
#endif
return new;
error:
abort_creds(new);
return NULL;
}
/**
* prepare_creds - Prepare a new set of credentials for modification
*
* Prepare a new set of task credentials for modification. A task's creds
* shouldn't generally be modified directly, therefore this function is used to
* prepare a new copy, which the caller then modifies and then commits by
* calling commit_creds().
*
* Preparation involves making a copy of the objective creds for modification.
*
* Returns a pointer to the new creds-to-be if successful, NULL otherwise.
*
* Call commit_creds() or abort_creds() to clean up.
*/
struct cred *prepare_creds(void)
{
struct task_struct *task = current;
const struct cred *old;
struct cred *new;
validate_process_creds();
new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
if (!new)
return NULL;
kdebug("prepare_creds() alloc %p", new);
old = task->cred;
memcpy(new, old, sizeof(struct cred));
atomic_set(&new->usage, 1);
set_cred_subscribers(new, 0);
get_group_info(new->group_info);
get_uid(new->user);
#ifdef CONFIG_KEYS
key_get(new->thread_keyring);
key_get(new->request_key_auth);
atomic_inc(&new->tgcred->usage);
#endif
#ifdef CONFIG_SECURITY
new->security = NULL;
#endif
if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
goto error;
validate_creds(new);
return new;
error:
abort_creds(new);
return NULL;
}
EXPORT_SYMBOL(prepare_creds);
/*
* Prepare credentials for current to perform an execve()
* - The caller must hold current->cred_guard_mutex
*/
struct cred *prepare_exec_creds(void)
{
struct thread_group_cred *tgcred = NULL;
struct cred *new;
#ifdef CONFIG_KEYS
tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
if (!tgcred)
return NULL;
#endif
new = prepare_creds();
if (!new) {
kfree(tgcred);
return new;
}
#ifdef CONFIG_KEYS
/* newly exec'd tasks don't get a thread keyring */
key_put(new->thread_keyring);
new->thread_keyring = NULL;
/* create a new per-thread-group creds for all this set of threads to
* share */
memcpy(tgcred, new->tgcred, sizeof(struct thread_group_cred));
atomic_set(&tgcred->usage, 1);
spin_lock_init(&tgcred->lock);
/* inherit the session keyring; new process keyring */
key_get(tgcred->session_keyring);
tgcred->process_keyring = NULL;
release_tgcred(new);
new->tgcred = tgcred;
#endif
return new;
}
/*
* prepare new credentials for the usermode helper dispatcher
*/
struct cred *prepare_usermodehelper_creds(void)
{
#ifdef CONFIG_KEYS
struct thread_group_cred *tgcred = NULL;
#endif
struct cred *new;
#ifdef CONFIG_KEYS
tgcred = kzalloc(sizeof(*new->tgcred), GFP_ATOMIC);
if (!tgcred)
return NULL;
#endif
new = kmem_cache_alloc(cred_jar, GFP_ATOMIC);
if (!new)
return NULL;
kdebug("prepare_usermodehelper_creds() alloc %p", new);
memcpy(new, &init_cred, sizeof(struct cred));
atomic_set(&new->usage, 1);
set_cred_subscribers(new, 0);
get_group_info(new->group_info);
get_uid(new->user);
#ifdef CONFIG_KEYS
new->thread_keyring = NULL;
new->request_key_auth = NULL;
new->jit_keyring = KEY_REQKEY_DEFL_DEFAULT;
atomic_set(&tgcred->usage, 1);
spin_lock_init(&tgcred->lock);
new->tgcred = tgcred;
#endif
#ifdef CONFIG_SECURITY
new->security = NULL;
#endif
if (security_prepare_creds(new, &init_cred, GFP_ATOMIC) < 0)
goto error;
validate_creds(new);
BUG_ON(atomic_read(&new->usage) != 1);
return new;
error:
put_cred(new);
return NULL;
}
/*
* Copy credentials for the new process created by fork()
*
* We share if we can, but under some circumstances we have to generate a new
* set.
*
* The new process gets the current process's subjective credentials as its
* objective and subjective credentials
*/
int copy_creds(struct task_struct *p, unsigned long clone_flags)
{
#ifdef CONFIG_KEYS
struct thread_group_cred *tgcred;
#endif
struct cred *new;
int ret;
mutex_init(&p->cred_guard_mutex);
if (
#ifdef CONFIG_KEYS
!p->cred->thread_keyring &&
#endif
clone_flags & CLONE_THREAD
) {
p->real_cred = get_cred(p->cred);
get_cred(p->cred);
alter_cred_subscribers(p->cred, 2);
kdebug("share_creds(%p{%d,%d})",
p->cred, atomic_read(&p->cred->usage),
read_cred_subscribers(p->cred));
atomic_inc(&p->cred->user->processes);
return 0;
}
new = prepare_creds();
if (!new)
return -ENOMEM;
if (clone_flags & CLONE_NEWUSER) {
ret = create_user_ns(new);
if (ret < 0)
goto error_put;
}
#ifdef CONFIG_KEYS
/* new threads get their own thread keyrings if their parent already
* had one */
if (new->thread_keyring) {
key_put(new->thread_keyring);
new->thread_keyring = NULL;
if (clone_flags & CLONE_THREAD)
install_thread_keyring_to_cred(new);
}
/* we share the process and session keyrings between all the threads in
* a process - this is slightly icky as we violate COW credentials a
* bit */
if (!(clone_flags & CLONE_THREAD)) {
tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
if (!tgcred) {
ret = -ENOMEM;
goto error_put;
}
atomic_set(&tgcred->usage, 1);
spin_lock_init(&tgcred->lock);
tgcred->process_keyring = NULL;
tgcred->session_keyring = key_get(new->tgcred->session_keyring);
release_tgcred(new);
new->tgcred = tgcred;
}
#endif
atomic_inc(&new->user->processes);
p->cred = p->real_cred = get_cred(new);
alter_cred_subscribers(new, 2);
validate_creds(new);
return 0;
error_put:
put_cred(new);
return ret;
}
/**
* commit_creds - Install new credentials upon the current task
* @new: The credentials to be assigned
*
* Install a new set of credentials to the current task, using RCU to replace
* the old set. Both the objective and the subjective credentials pointers are
* updated. This function may not be called if the subjective credentials are
* in an overridden state.
*
* This function eats the caller's reference to the new credentials.
*
* Always returns 0 thus allowing this function to be tail-called at the end
* of, say, sys_setgid().
*/
int commit_creds(struct cred *new)
{
struct task_struct *task = current;
const struct cred *old = task->real_cred;
kdebug("commit_creds(%p{%d,%d})", new,
atomic_read(&new->usage),
read_cred_subscribers(new));
BUG_ON(task->cred != old);
#ifdef CONFIG_DEBUG_CREDENTIALS
BUG_ON(read_cred_subscribers(old) < 2);
validate_creds(old);
validate_creds(new);
#endif
BUG_ON(atomic_read(&new->usage) < 1);
security_commit_creds(new, old);
get_cred(new); /* we will require a ref for the subj creds too */
/* dumpability changes */
if (old->euid != new->euid ||
old->egid != new->egid ||
old->fsuid != new->fsuid ||
old->fsgid != new->fsgid ||
!cap_issubset(new->cap_permitted, old->cap_permitted)) {
if (task->mm)
set_dumpable(task->mm, suid_dumpable);
task->pdeath_signal = 0;
smp_wmb();
}
/* alter the thread keyring */
if (new->fsuid != old->fsuid)
key_fsuid_changed(task);
if (new->fsgid != old->fsgid)
key_fsgid_changed(task);
/* do it
* - What if a process setreuid()'s and this brings the
* new uid over his NPROC rlimit? We can check this now
* cheaply with the new uid cache, so if it matters
* we should be checking for it. -DaveM
*/
alter_cred_subscribers(new, 2);
if (new->user != old->user)
atomic_inc(&new->user->processes);
rcu_assign_pointer(task->real_cred, new);
rcu_assign_pointer(task->cred, new);
if (new->user != old->user)
atomic_dec(&old->user->processes);
alter_cred_subscribers(old, -2);
sched_switch_user(task);
/* send notifications */
if (new->uid != old->uid ||
new->euid != old->euid ||
new->suid != old->suid ||
new->fsuid != old->fsuid)
proc_id_connector(task, PROC_EVENT_UID);
if (new->gid != old->gid ||
new->egid != old->egid ||
new->sgid != old->sgid ||
new->fsgid != old->fsgid)
proc_id_connector(task, PROC_EVENT_GID);
/* release the old obj and subj refs both */
put_cred(old);
put_cred(old);
return 0;
}
EXPORT_SYMBOL(commit_creds);
/**
* abort_creds - Discard a set of credentials and unlock the current task
* @new: The credentials that were going to be applied
*
* Discard a set of credentials that were under construction and unlock the
* current task.
*/
void abort_creds(struct cred *new)
{
kdebug("abort_creds(%p{%d,%d})", new,
atomic_read(&new->usage),
read_cred_subscribers(new));
#ifdef CONFIG_DEBUG_CREDENTIALS
BUG_ON(read_cred_subscribers(new) != 0);
#endif
BUG_ON(atomic_read(&new->usage) < 1);
put_cred(new);
}
EXPORT_SYMBOL(abort_creds);
/**
* override_creds - Override the current process's subjective credentials
* @new: The credentials to be assigned
*
* Install a set of temporary override subjective credentials on the current
* process, returning the old set for later reversion.
*/
const struct cred *override_creds(const struct cred *new)
{
const struct cred *old = current->cred;
kdebug("override_creds(%p{%d,%d})", new,
atomic_read(&new->usage),
read_cred_subscribers(new));
validate_creds(old);
validate_creds(new);
get_cred(new);
alter_cred_subscribers(new, 1);
rcu_assign_pointer(current->cred, new);
alter_cred_subscribers(old, -1);
kdebug("override_creds() = %p{%d,%d}", old,
atomic_read(&old->usage),
read_cred_subscribers(old));
return old;
}
EXPORT_SYMBOL(override_creds);
/**
* revert_creds - Revert a temporary subjective credentials override
* @old: The credentials to be restored
*
* Revert a temporary set of override subjective credentials to an old set,
* discarding the override set.
*/
void revert_creds(const struct cred *old)
{
const struct cred *override = current->cred;
kdebug("revert_creds(%p{%d,%d})", old,
atomic_read(&old->usage),
read_cred_subscribers(old));
validate_creds(old);
validate_creds(override);
alter_cred_subscribers(old, 1);
rcu_assign_pointer(current->cred, old);
alter_cred_subscribers(override, -1);
put_cred(override);
}
EXPORT_SYMBOL(revert_creds);
/*
* initialise the credentials stuff
*/
void __init cred_init(void)
{
/* allocate a slab in which we can store credentials */
cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
}
/**
* prepare_kernel_cred - Prepare a set of credentials for a kernel service
* @daemon: A userspace daemon to be used as a reference
*
* Prepare a set of credentials for a kernel service. This can then be used to
* override a task's own credentials so that work can be done on behalf of that
* task that requires a different subjective context.
*
* @daemon is used to provide a base for the security record, but can be NULL.
* If @daemon is supplied, then the security data will be derived from that;
* otherwise they'll be set to 0 and no groups, full capabilities and no keys.
*
* The caller may change these controls afterwards if desired.
*
* Returns the new credentials or NULL if out of memory.
*
* Does not take, and does not return holding current->cred_replace_mutex.
*/
struct cred *prepare_kernel_cred(struct task_struct *daemon)
{
const struct cred *old;
struct cred *new;
new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
if (!new)
return NULL;
kdebug("prepare_kernel_cred() alloc %p", new);
if (daemon)
old = get_task_cred(daemon);
else
old = get_cred(&init_cred);
validate_creds(old);
*new = *old;
get_uid(new->user);
get_group_info(new->group_info);
#ifdef CONFIG_KEYS
atomic_inc(&init_tgcred.usage);
new->tgcred = &init_tgcred;
new->request_key_auth = NULL;
new->thread_keyring = NULL;
new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
#endif
#ifdef CONFIG_SECURITY
new->security = NULL;
#endif
if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
goto error;
atomic_set(&new->usage, 1);
set_cred_subscribers(new, 0);
put_cred(old);
validate_creds(new);
return new;
error:
put_cred(new);
put_cred(old);
return NULL;
}
EXPORT_SYMBOL(prepare_kernel_cred);
/**
* set_security_override - Set the security ID in a set of credentials
* @new: The credentials to alter
* @secid: The LSM security ID to set
*
* Set the LSM security ID in a set of credentials so that the subjective
* security is overridden when an alternative set of credentials is used.
*/
int set_security_override(struct cred *new, u32 secid)
{
return security_kernel_act_as(new, secid);
}
EXPORT_SYMBOL(set_security_override);
/**
* set_security_override_from_ctx - Set the security ID in a set of credentials
* @new: The credentials to alter
* @secctx: The LSM security context to generate the security ID from.
*
* Set the LSM security ID in a set of credentials so that the subjective
* security is overridden when an alternative set of credentials is used. The
* security ID is specified in string form as a security context to be
* interpreted by the LSM.
*/
int set_security_override_from_ctx(struct cred *new, const char *secctx)
{
u32 secid;
int ret;
ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
if (ret < 0)
return ret;
return set_security_override(new, secid);
}
EXPORT_SYMBOL(set_security_override_from_ctx);
/**
* set_create_files_as - Set the LSM file create context in a set of credentials
* @new: The credentials to alter
* @inode: The inode to take the context from
*
* Change the LSM file creation context in a set of credentials to be the same
* as the object context of the specified inode, so that the new inodes have
* the same MAC context as that inode.
*/
int set_create_files_as(struct cred *new, struct inode *inode)
{
new->fsuid = inode->i_uid;
new->fsgid = inode->i_gid;
return security_kernel_create_files_as(new, inode);
}
EXPORT_SYMBOL(set_create_files_as);
#ifdef CONFIG_DEBUG_CREDENTIALS
/*
* dump invalid credentials
*/
static void dump_invalid_creds(const struct cred *cred, const char *label,
const struct task_struct *tsk)
{
printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n",
label, cred,
cred == &init_cred ? "[init]" : "",
cred == tsk->real_cred ? "[real]" : "",
cred == tsk->cred ? "[eff]" : "");
printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n",
cred->magic, cred->put_addr);
printk(KERN_ERR "CRED: ->usage=%d, subscr=%d\n",
atomic_read(&cred->usage),
read_cred_subscribers(cred));
printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n",
cred->uid, cred->euid, cred->suid, cred->fsuid);
printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n",
cred->gid, cred->egid, cred->sgid, cred->fsgid);
#ifdef CONFIG_SECURITY
printk(KERN_ERR "CRED: ->security is %p\n", cred->security);
if ((unsigned long) cred->security >= PAGE_SIZE &&
(((unsigned long) cred->security & 0xffffff00) !=
(POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)))
printk(KERN_ERR "CRED: ->security {%x, %x}\n",
((u32*)cred->security)[0],
((u32*)cred->security)[1]);
#endif
}
/*
* report use of invalid credentials
*/
void __invalid_creds(const struct cred *cred, const char *file, unsigned line)
{
printk(KERN_ERR "CRED: Invalid credentials\n");
printk(KERN_ERR "CRED: At %s:%u\n", file, line);
dump_invalid_creds(cred, "Specified", current);
BUG();
}
EXPORT_SYMBOL(__invalid_creds);
/*
* check the credentials on a process
*/
void __validate_process_creds(struct task_struct *tsk,
const char *file, unsigned line)
{
if (tsk->cred == tsk->real_cred) {
if (unlikely(read_cred_subscribers(tsk->cred) < 2 ||
creds_are_invalid(tsk->cred)))
goto invalid_creds;
} else {
if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 ||
read_cred_subscribers(tsk->cred) < 1 ||
creds_are_invalid(tsk->real_cred) ||
creds_are_invalid(tsk->cred)))
goto invalid_creds;
}
return;
invalid_creds:
printk(KERN_ERR "CRED: Invalid process credentials\n");
printk(KERN_ERR "CRED: At %s:%u\n", file, line);
dump_invalid_creds(tsk->real_cred, "Real", tsk);
if (tsk->cred != tsk->real_cred)
dump_invalid_creds(tsk->cred, "Effective", tsk);
else
printk(KERN_ERR "CRED: Effective creds == Real creds\n");
BUG();
}
EXPORT_SYMBOL(__validate_process_creds);
/*
* check creds for do_exit()
*/
void validate_creds_for_do_exit(struct task_struct *tsk)
{
kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})",
tsk->real_cred, tsk->cred,
atomic_read(&tsk->cred->usage),
read_cred_subscribers(tsk->cred));
__validate_process_creds(tsk, __FILE__, __LINE__);
}
#endif /* CONFIG_DEBUG_CREDENTIALS */
Reference in a new issue View git blame Copy permalink