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-rw-r--r--security/keys/process_keys.c213
1 files changed, 125 insertions, 88 deletions
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 2eb0e47..9b0369c 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -1,6 +1,6 @@
/* process_keys.c: management of a process's keyrings
*
- * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
@@ -38,10 +38,9 @@ struct key root_user_keyring = {
.serial = 2,
.type = &key_type_keyring,
.user = &root_key_user,
- .lock = RW_LOCK_UNLOCKED,
.sem = __RWSEM_INITIALIZER(root_user_keyring.sem),
.perm = KEY_USR_ALL,
- .flags = KEY_FLAG_INSTANTIATED,
+ .flags = 1 << KEY_FLAG_INSTANTIATED,
.description = "_uid.0",
#ifdef KEY_DEBUGGING
.magic = KEY_DEBUG_MAGIC,
@@ -54,10 +53,9 @@ struct key root_session_keyring = {
.serial = 1,
.type = &key_type_keyring,
.user = &root_key_user,
- .lock = RW_LOCK_UNLOCKED,
.sem = __RWSEM_INITIALIZER(root_session_keyring.sem),
.perm = KEY_USR_ALL,
- .flags = KEY_FLAG_INSTANTIATED,
+ .flags = 1 << KEY_FLAG_INSTANTIATED,
.description = "_uid_ses.0",
#ifdef KEY_DEBUGGING
.magic = KEY_DEBUG_MAGIC,
@@ -167,7 +165,7 @@ int install_thread_keyring(struct task_struct *tsk)
/*
* make sure a process keyring is installed
*/
-static int install_process_keyring(struct task_struct *tsk)
+int install_process_keyring(struct task_struct *tsk)
{
unsigned long flags;
struct key *keyring;
@@ -183,7 +181,7 @@ static int install_process_keyring(struct task_struct *tsk)
goto error;
}
- /* attach or swap keyrings */
+ /* attach keyring */
spin_lock_irqsave(&tsk->sighand->siglock, flags);
if (!tsk->signal->process_keyring) {
tsk->signal->process_keyring = keyring;
@@ -229,12 +227,14 @@ static int install_session_keyring(struct task_struct *tsk,
/* install the keyring */
spin_lock_irqsave(&tsk->sighand->siglock, flags);
- old = tsk->signal->session_keyring;
- tsk->signal->session_keyring = keyring;
+ old = rcu_dereference(tsk->signal->session_keyring);
+ rcu_assign_pointer(tsk->signal->session_keyring, keyring);
spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
ret = 0;
+ /* we're using RCU on the pointer */
+ synchronize_rcu();
key_put(old);
error:
return ret;
@@ -247,8 +247,6 @@ static int install_session_keyring(struct task_struct *tsk,
*/
int copy_thread_group_keys(struct task_struct *tsk)
{
- unsigned long flags;
-
key_check(current->thread_group->session_keyring);
key_check(current->thread_group->process_keyring);
@@ -256,10 +254,10 @@ int copy_thread_group_keys(struct task_struct *tsk)
tsk->signal->process_keyring = NULL;
/* same session keyring */
- spin_lock_irqsave(&current->sighand->siglock, flags);
+ rcu_read_lock();
tsk->signal->session_keyring =
- key_get(current->signal->session_keyring);
- spin_unlock_irqrestore(&current->sighand->siglock, flags);
+ key_get(rcu_dereference(current->signal->session_keyring));
+ rcu_read_unlock();
return 0;
@@ -349,9 +347,7 @@ void key_fsuid_changed(struct task_struct *tsk)
/* update the ownership of the thread keyring */
if (tsk->thread_keyring) {
down_write(&tsk->thread_keyring->sem);
- write_lock(&tsk->thread_keyring->lock);
tsk->thread_keyring->uid = tsk->fsuid;
- write_unlock(&tsk->thread_keyring->lock);
up_write(&tsk->thread_keyring->sem);
}
@@ -366,9 +362,7 @@ void key_fsgid_changed(struct task_struct *tsk)
/* update the ownership of the thread keyring */
if (tsk->thread_keyring) {
down_write(&tsk->thread_keyring->sem);
- write_lock(&tsk->thread_keyring->lock);
tsk->thread_keyring->gid = tsk->fsgid;
- write_unlock(&tsk->thread_keyring->lock);
up_write(&tsk->thread_keyring->sem);
}
@@ -382,13 +376,13 @@ void key_fsgid_changed(struct task_struct *tsk)
* - we return -EAGAIN if we didn't find any matching key
* - we return -ENOKEY if we found only negative matching keys
*/
-struct key *search_process_keyrings_aux(struct key_type *type,
- const void *description,
- key_match_func_t match)
+struct key *search_process_keyrings(struct key_type *type,
+ const void *description,
+ key_match_func_t match,
+ struct task_struct *context)
{
- struct task_struct *tsk = current;
- unsigned long flags;
- struct key *key, *ret, *err, *tmp;
+ struct request_key_auth *rka;
+ struct key *key, *ret, *err, *instkey;
/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
* searchable, but we failed to find a key or we found a negative key;
@@ -402,9 +396,9 @@ struct key *search_process_keyrings_aux(struct key_type *type,
err = ERR_PTR(-EAGAIN);
/* search the thread keyring first */
- if (tsk->thread_keyring) {
- key = keyring_search_aux(tsk->thread_keyring, type,
- description, match);
+ if (context->thread_keyring) {
+ key = keyring_search_aux(context->thread_keyring,
+ context, type, description, match);
if (!IS_ERR(key))
goto found;
@@ -422,9 +416,9 @@ struct key *search_process_keyrings_aux(struct key_type *type,
}
/* search the process keyring second */
- if (tsk->signal->process_keyring) {
- key = keyring_search_aux(tsk->signal->process_keyring,
- type, description, match);
+ if (context->signal->process_keyring) {
+ key = keyring_search_aux(context->signal->process_keyring,
+ context, type, description, match);
if (!IS_ERR(key))
goto found;
@@ -441,52 +435,93 @@ struct key *search_process_keyrings_aux(struct key_type *type,
}
}
- /* search the session keyring last */
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ /* search the session keyring */
+ if (context->signal->session_keyring) {
+ rcu_read_lock();
+ key = keyring_search_aux(
+ rcu_dereference(context->signal->session_keyring),
+ context, type, description, match);
+ rcu_read_unlock();
- tmp = tsk->signal->session_keyring;
- if (!tmp)
- tmp = tsk->user->session_keyring;
- atomic_inc(&tmp->usage);
+ if (!IS_ERR(key))
+ goto found;
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ switch (PTR_ERR(key)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key;
+ break;
+ default:
+ err = key;
+ break;
+ }
+
+ /* if this process has a session keyring and that has an
+ * instantiation authorisation key in the bottom level, then we
+ * also search the keyrings of the process mentioned there */
+ if (context != current)
+ goto no_key;
+
+ rcu_read_lock();
+ instkey = __keyring_search_one(
+ rcu_dereference(context->signal->session_keyring),
+ &key_type_request_key_auth, NULL, 0);
+ rcu_read_unlock();
+
+ if (IS_ERR(instkey))
+ goto no_key;
+
+ rka = instkey->payload.data;
- key = keyring_search_aux(tmp, type, description, match);
- key_put(tmp);
- if (!IS_ERR(key))
- goto found;
+ key = search_process_keyrings(type, description, match,
+ rka->context);
+ key_put(instkey);
- switch (PTR_ERR(key)) {
- case -EAGAIN: /* no key */
- if (ret)
+ if (!IS_ERR(key))
+ goto found;
+
+ switch (PTR_ERR(key)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key;
break;
- case -ENOKEY: /* negative key */
- ret = key;
- break;
- default:
- err = key;
- break;
+ default:
+ err = key;
+ break;
+ }
+ }
+ /* or search the user-session keyring */
+ else {
+ key = keyring_search_aux(context->user->session_keyring,
+ context, type, description, match);
+ if (!IS_ERR(key))
+ goto found;
+
+ switch (PTR_ERR(key)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key;
+ break;
+ default:
+ err = key;
+ break;
+ }
}
+
+no_key:
/* no key - decide on the error we're going to go for */
key = ret ? ret : err;
- found:
+found:
return key;
-} /* end search_process_keyrings_aux() */
-
-/*****************************************************************************/
-/*
- * search the process keyrings for the first matching key
- * - we return -EAGAIN if we didn't find any matching key
- * - we return -ENOKEY if we found only negative matching keys
- */
-struct key *search_process_keyrings(struct key_type *type,
- const char *description)
-{
- return search_process_keyrings_aux(type, description, type->match);
-
} /* end search_process_keyrings() */
/*****************************************************************************/
@@ -495,72 +530,73 @@ struct key *search_process_keyrings(struct key_type *type,
* - don't create special keyrings unless so requested
* - partially constructed keys aren't found unless requested
*/
-struct key *lookup_user_key(key_serial_t id, int create, int partial,
- key_perm_t perm)
+struct key *lookup_user_key(struct task_struct *context, key_serial_t id,
+ int create, int partial, key_perm_t perm)
{
- struct task_struct *tsk = current;
- unsigned long flags;
struct key *key;
int ret;
+ if (!context)
+ context = current;
+
key = ERR_PTR(-ENOKEY);
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
- if (!tsk->thread_keyring) {
+ if (!context->thread_keyring) {
if (!create)
goto error;
- ret = install_thread_keyring(tsk);
+ ret = install_thread_keyring(context);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
- key = tsk->thread_keyring;
+ key = context->thread_keyring;
atomic_inc(&key->usage);
break;
case KEY_SPEC_PROCESS_KEYRING:
- if (!tsk->signal->process_keyring) {
+ if (!context->signal->process_keyring) {
if (!create)
goto error;
- ret = install_process_keyring(tsk);
+ ret = install_process_keyring(context);
if (ret < 0) {
key = ERR_PTR(ret);
goto error;
}
}
- key = tsk->signal->process_keyring;
+ key = context->signal->process_keyring;
atomic_inc(&key->usage);
break;
case KEY_SPEC_SESSION_KEYRING:
- if (!tsk->signal->session_keyring) {
+ if (!context->signal->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = install_session_keyring(
- tsk, tsk->user->session_keyring);
+ context, context->user->session_keyring);
if (ret < 0)
goto error;
}
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
- key = tsk->signal->session_keyring;
+ rcu_read_lock();
+ key = rcu_dereference(context->signal->session_keyring);
atomic_inc(&key->usage);
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ rcu_read_unlock();
break;
case KEY_SPEC_USER_KEYRING:
- key = tsk->user->uid_keyring;
+ key = context->user->uid_keyring;
atomic_inc(&key->usage);
break;
case KEY_SPEC_USER_SESSION_KEYRING:
- key = tsk->user->session_keyring;
+ key = context->user->session_keyring;
atomic_inc(&key->usage);
break;
@@ -580,7 +616,7 @@ struct key *lookup_user_key(key_serial_t id, int create, int partial,
break;
}
- /* check the status and permissions */
+ /* check the status */
if (perm) {
ret = key_validate(key);
if (ret < 0)
@@ -588,11 +624,13 @@ struct key *lookup_user_key(key_serial_t id, int create, int partial,
}
ret = -EIO;
- if (!partial && !(key->flags & KEY_FLAG_INSTANTIATED))
+ if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto invalid_key;
+ /* check the permissions */
ret = -EACCES;
- if (!key_permission(key, perm))
+
+ if (!key_task_permission(key, context, perm))
goto invalid_key;
error:
@@ -615,7 +653,6 @@ struct key *lookup_user_key(key_serial_t id, int create, int partial,
long join_session_keyring(const char *name)
{
struct task_struct *tsk = current;
- unsigned long flags;
struct key *keyring;
long ret;
@@ -625,9 +662,9 @@ long join_session_keyring(const char *name)
if (ret < 0)
goto error;
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
- ret = tsk->signal->session_keyring->serial;
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ rcu_read_lock();
+ ret = rcu_dereference(tsk->signal->session_keyring)->serial;
+ rcu_read_unlock();
goto error;
}
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