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yaml
---
r: 344826
b: refs/heads/master
c: 3a50597
h: refs/heads/master
v: v3
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David Howells committed Oct 2, 2012
1 parent 160fe73 commit 99aee7e
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Showing 6 changed files with 51 additions and 182 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: a84a921978b7d56e0e4b87ffaca6367429b4d8ff
refs/heads/master: 3a50597de8635cd05133bd12c95681c82fe7b878
17 changes: 2 additions & 15 deletions trunk/include/linux/cred.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,21 +76,6 @@ extern int groups_search(const struct group_info *, kgid_t);
extern int in_group_p(kgid_t);
extern int in_egroup_p(kgid_t);

/*
* The common credentials for a thread group
* - shared by CLONE_THREAD
*/
#ifdef CONFIG_KEYS
struct thread_group_cred {
atomic_t usage;
pid_t tgid; /* thread group process ID */
spinlock_t lock;
struct key __rcu *session_keyring; /* keyring inherited over fork */
struct key *process_keyring; /* keyring private to this process */
struct rcu_head rcu; /* RCU deletion hook */
};
#endif

/*
* The security context of a task
*
Expand Down Expand Up @@ -139,6 +124,8 @@ struct cred {
#ifdef CONFIG_KEYS
unsigned char jit_keyring; /* default keyring to attach requested
* keys to */
struct key __rcu *session_keyring; /* keyring inherited over fork */
struct key *process_keyring; /* keyring private to this process */
struct key *thread_keyring; /* keyring private to this thread */
struct key *request_key_auth; /* assumed request_key authority */
struct thread_group_cred *tgcred; /* thread-group shared credentials */
Expand Down
127 changes: 15 additions & 112 deletions trunk/kernel/cred.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,17 +29,6 @@

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(init_cred.tgcred.lock),
};
#endif

/*
* The initial credentials for the initial task
*/
Expand All @@ -65,9 +54,6 @@ struct cred init_cred = {
.user = INIT_USER,
.user_ns = &init_user_ns,
.group_info = &init_groups,
#ifdef CONFIG_KEYS
.tgcred = &init_tgcred,
#endif
};

static inline void set_cred_subscribers(struct cred *cred, int n)
Expand Down Expand Up @@ -95,36 +81,6 @@ static inline void alter_cred_subscribers(const struct cred *_cred, int n)
#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
*/
Expand All @@ -150,9 +106,10 @@ static void put_cred_rcu(struct rcu_head *rcu)
#endif

security_cred_free(cred);
key_put(cred->session_keyring);
key_put(cred->process_keyring);
key_put(cred->thread_keyring);
key_put(cred->request_key_auth);
release_tgcred(cred);
if (cred->group_info)
put_group_info(cred->group_info);
free_uid(cred->user);
Expand Down Expand Up @@ -246,15 +203,6 @@ struct cred *cred_alloc_blank(void)
if (!new)
return NULL;

#ifdef CONFIG_KEYS
new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL);
if (!new->tgcred) {
kmem_cache_free(cred_jar, new);
return NULL;
}
atomic_set(&new->tgcred->usage, 1);
#endif

atomic_set(&new->usage, 1);
#ifdef CONFIG_DEBUG_CREDENTIALS
new->magic = CRED_MAGIC;
Expand Down Expand Up @@ -308,9 +256,10 @@ struct cred *prepare_creds(void)
get_user_ns(new->user_ns);

#ifdef CONFIG_KEYS
key_get(new->session_keyring);
key_get(new->process_keyring);
key_get(new->thread_keyring);
key_get(new->request_key_auth);
atomic_inc(&new->tgcred->usage);
#endif

#ifdef CONFIG_SECURITY
Expand All @@ -334,39 +283,20 @@ EXPORT_SYMBOL(prepare_creds);
*/
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);
if (!new)
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;
key_put(new->process_keyring);
new->process_keyring = NULL;
#endif

return new;
Expand All @@ -383,9 +313,6 @@ struct cred *prepare_exec_creds(void)
*/
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;

Expand Down Expand Up @@ -425,22 +352,12 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
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 */
/* The process keyring is only shared between the threads in a process;
* anything outside of those threads doesn't inherit.
*/
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;
key_put(new->process_keyring);
new->process_keyring = NULL;
}
#endif

Expand Down Expand Up @@ -643,24 +560,13 @@ void __init cred_init(void)
*/
struct cred *prepare_kernel_cred(struct task_struct *daemon)
{
#ifdef CONFIG_KEYS
struct thread_group_cred *tgcred;
#endif
const struct cred *old;
struct cred *new;

new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
if (!new)
return NULL;

#ifdef CONFIG_KEYS
tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
if (!tgcred) {
kmem_cache_free(cred_jar, new);
return NULL;
}
#endif

kdebug("prepare_kernel_cred() alloc %p", new);

if (daemon)
Expand All @@ -678,13 +584,10 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon)
get_group_info(new->group_info);

#ifdef CONFIG_KEYS
atomic_set(&tgcred->usage, 1);
spin_lock_init(&tgcred->lock);
tgcred->process_keyring = NULL;
tgcred->session_keyring = NULL;
new->tgcred = tgcred;
new->request_key_auth = NULL;
new->session_keyring = NULL;
new->process_keyring = NULL;
new->thread_keyring = NULL;
new->request_key_auth = NULL;
new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
#endif

Expand Down
11 changes: 6 additions & 5 deletions trunk/security/keys/keyctl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1475,7 +1475,8 @@ long keyctl_session_to_parent(void)
goto error_keyring;
newwork = &cred->rcu;

cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
cred->session_keyring = key_ref_to_ptr(keyring_r);
keyring_r = NULL;
init_task_work(newwork, key_change_session_keyring);

me = current;
Expand All @@ -1500,7 +1501,7 @@ long keyctl_session_to_parent(void)
mycred = current_cred();
pcred = __task_cred(parent);
if (mycred == pcred ||
mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) {
mycred->session_keyring == pcred->session_keyring) {
ret = 0;
goto unlock;
}
Expand All @@ -1516,9 +1517,9 @@ long keyctl_session_to_parent(void)
goto unlock;

/* the keyrings must have the same UID */
if ((pcred->tgcred->session_keyring &&
pcred->tgcred->session_keyring->uid != mycred->euid) ||
mycred->tgcred->session_keyring->uid != mycred->euid)
if ((pcred->session_keyring &&
pcred->session_keyring->uid != mycred->euid) ||
mycred->session_keyring->uid != mycred->euid)
goto unlock;

/* cancel an already pending keyring replacement */
Expand Down
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