#include <linux/security.h>
#include <linux/user_namespace.h>
#include <linux/uaccess.h>
+#include <linux/init_task.h>
#include <keys/request_key_auth-type.h>
#include "internal.h"
/* Session keyring create vs join semaphore */
static DEFINE_MUTEX(key_session_mutex);
-/* User keyring creation semaphore */
-static DEFINE_MUTEX(key_user_keyring_mutex);
-
/* The root user's tracking struct */
struct key_user root_key_user = {
.usage = REFCOUNT_INIT(3),
.uid = GLOBAL_ROOT_UID,
};
+static struct key_acl user_reg_keyring_acl = {
+ .usage = REFCOUNT_INIT(1),
+ .possessor_viewable = true,
+ .nr_ace = 2,
+ .aces = {
+ KEY_POSSESSOR_ACE(KEY_ACE_WRITE | KEY_ACE_SEARCH),
+ KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_READ),
+ }
+};
+
+static struct key_acl user_keyring_acl = {
+ .usage = REFCOUNT_INIT(1),
+ .possessor_viewable = true,
+ .nr_ace = 2,
+ .aces = {
+ KEY_POSSESSOR_ACE(KEY_ACE_VIEW | KEY_ACE_READ | KEY_ACE_WRITE |
+ KEY_ACE_SEARCH | KEY_ACE_LINK),
+ KEY_OWNER_ACE(KEY_ACE__PERMS & ~(KEY_ACE_JOIN | KEY_ACE_SET_SECURITY)),
+ }
+};
+
+static struct key_acl session_keyring_acl = {
+ .usage = REFCOUNT_INIT(1),
+ .possessor_viewable = true,
+ .nr_ace = 2,
+ .aces = {
+ KEY_POSSESSOR_ACE(KEY_ACE__PERMS & ~KEY_ACE_JOIN),
+ KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_READ),
+ }
+};
+
+static struct key_acl thread_and_process_keyring_acl = {
+ .usage = REFCOUNT_INIT(1),
+ .possessor_viewable = true,
+ .nr_ace = 2,
+ .aces = {
+ KEY_POSSESSOR_ACE(KEY_ACE__PERMS & ~(KEY_ACE_JOIN | KEY_ACE_SET_SECURITY)),
+ KEY_OWNER_ACE(KEY_ACE_VIEW),
+ }
+};
+
/*
- * Install the user and user session keyrings for the current process's UID.
+ * Get or create a user register keyring.
*/
-int install_user_keyrings(void)
+static struct key *get_user_register(struct user_namespace *user_ns)
{
- struct user_struct *user;
- const struct cred *cred;
- struct key *uid_keyring, *session_keyring;
- key_perm_t user_keyring_perm;
- char buf[20];
- int ret;
- uid_t uid;
+ struct key *reg_keyring = READ_ONCE(user_ns->user_keyring_register);
- user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
- cred = current_cred();
- user = cred->user;
- uid = from_kuid(cred->user_ns, user->uid);
+ if (reg_keyring)
+ return reg_keyring;
- kenter("%p{%u}", user, uid);
+ down_write(&user_ns->keyring_sem);
- if (READ_ONCE(user->uid_keyring) && READ_ONCE(user->session_keyring)) {
- kleave(" = 0 [exist]");
- return 0;
+ /* Make sure there's a register keyring. It gets owned by the
+ * user_namespace's owner.
+ */
+ reg_keyring = user_ns->user_keyring_register;
+ if (!reg_keyring) {
+ reg_keyring = keyring_alloc(".user_reg",
+ user_ns->owner, INVALID_GID,
+ &init_cred, &user_reg_keyring_acl,
+ 0, NULL, NULL);
+ if (!IS_ERR(reg_keyring))
+ smp_store_release(&user_ns->user_keyring_register,
+ reg_keyring);
}
- mutex_lock(&key_user_keyring_mutex);
- ret = 0;
+ up_write(&user_ns->keyring_sem);
+
+ /* We don't return a ref since the keyring is pinned by the user_ns */
+ return reg_keyring;
+}
+
+/*
+ * Look up the user and user session keyrings for the current process's UID,
+ * creating them if they don't exist.
+ */
+int look_up_user_keyrings(struct key **_user_keyring,
+ struct key **_user_session_keyring)
+{
+ const struct cred *cred = current_cred();
+ struct user_namespace *user_ns = current_user_ns();
+ struct key *reg_keyring, *uid_keyring, *session_keyring;
+ key_ref_t uid_keyring_r, session_keyring_r;
+ uid_t uid = from_kuid(user_ns, cred->user->uid);
+ char buf[20];
+ int ret;
- if (!user->uid_keyring) {
- /* get the UID-specific keyring
- * - there may be one in existence already as it may have been
- * pinned by a session, but the user_struct pointing to it
- * may have been destroyed by setuid */
- sprintf(buf, "_uid.%u", uid);
+ kenter("%u", uid);
+
+ reg_keyring = get_user_register(user_ns);
+ if (IS_ERR(reg_keyring))
+ return PTR_ERR(reg_keyring);
+
+ down_write(&user_ns->keyring_sem);
+ ret = 0;
- uid_keyring = find_keyring_by_name(buf, true);
+ /* Get the user keyring. Note that there may be one in existence
+ * already as it may have been pinned by a session, but the user_struct
+ * pointing to it may have been destroyed by setuid.
+ */
+ snprintf(buf, sizeof(buf), "_uid.%u", uid);
+ uid_keyring_r = keyring_search(make_key_ref(reg_keyring, true),
+ &key_type_keyring, buf, false);
+ kdebug("_uid %p", uid_keyring_r);
+ if (uid_keyring_r == ERR_PTR(-EAGAIN)) {
+ uid_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID,
+ cred, &user_keyring_acl,
+ KEY_ALLOC_UID_KEYRING |
+ KEY_ALLOC_IN_QUOTA,
+ NULL, reg_keyring);
if (IS_ERR(uid_keyring)) {
- uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
- cred, user_keyring_perm,
- KEY_ALLOC_UID_KEYRING |
- KEY_ALLOC_IN_QUOTA,
- NULL, NULL);
- if (IS_ERR(uid_keyring)) {
- ret = PTR_ERR(uid_keyring);
- goto error;
- }
+ ret = PTR_ERR(uid_keyring);
+ goto error;
}
+ } else if (IS_ERR(uid_keyring_r)) {
+ ret = PTR_ERR(uid_keyring_r);
+ goto error;
+ } else {
+ uid_keyring = key_ref_to_ptr(uid_keyring_r);
+ }
- /* get a default session keyring (which might also exist
- * already) */
- sprintf(buf, "_uid_ses.%u", uid);
-
- session_keyring = find_keyring_by_name(buf, true);
+ /* Get a default session keyring (which might also exist already) */
+ snprintf(buf, sizeof(buf), "_uid_ses.%u", uid);
+ session_keyring_r = keyring_search(make_key_ref(reg_keyring, true),
+ &key_type_keyring, buf, false);
+ kdebug("_uid_ses %p", session_keyring_r);
+ if (session_keyring_r == ERR_PTR(-EAGAIN)) {
+ session_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID,
+ cred, &user_keyring_acl,
+ KEY_ALLOC_UID_KEYRING |
+ KEY_ALLOC_IN_QUOTA,
+ NULL, NULL);
if (IS_ERR(session_keyring)) {
- session_keyring =
- keyring_alloc(buf, user->uid, INVALID_GID,
- cred, user_keyring_perm,
- KEY_ALLOC_UID_KEYRING |
- KEY_ALLOC_IN_QUOTA,
- NULL, NULL);
- if (IS_ERR(session_keyring)) {
- ret = PTR_ERR(session_keyring);
- goto error_release;
- }
-
- /* we install a link from the user session keyring to
- * the user keyring */
- ret = key_link(session_keyring, uid_keyring);
- if (ret < 0)
- goto error_release_both;
+ ret = PTR_ERR(session_keyring);
+ goto error_release;
}
- /* install the keyrings */
- /* paired with READ_ONCE() */
- smp_store_release(&user->uid_keyring, uid_keyring);
- /* paired with READ_ONCE() */
- smp_store_release(&user->session_keyring, session_keyring);
+ /* We install a link from the user session keyring to
+ * the user keyring.
+ */
+ ret = key_link(session_keyring, uid_keyring);
+ if (ret < 0)
+ goto error_release_session;
+
+ /* And only then link the user-session keyring to the
+ * register.
+ */
+ ret = key_link(reg_keyring, session_keyring);
+ if (ret < 0)
+ goto error_release_session;
+ } else if (IS_ERR(session_keyring_r)) {
+ ret = PTR_ERR(session_keyring_r);
+ goto error_release;
+ } else {
+ session_keyring = key_ref_to_ptr(session_keyring_r);
}
- mutex_unlock(&key_user_keyring_mutex);
+ up_write(&user_ns->keyring_sem);
+
+ if (_user_session_keyring)
+ *_user_session_keyring = session_keyring;
+ else
+ key_put(session_keyring);
+ if (_user_keyring)
+ *_user_keyring = uid_keyring;
+ else
+ key_put(uid_keyring);
kleave(" = 0");
return 0;
-error_release_both:
+error_release_session:
key_put(session_keyring);
error_release:
key_put(uid_keyring);
error:
- mutex_unlock(&key_user_keyring_mutex);
+ up_write(&user_ns->keyring_sem);
kleave(" = %d", ret);
return ret;
}
+/*
+ * Get the user session keyring if it exists, but don't create it if it
+ * doesn't.
+ */
+struct key *get_user_session_keyring_rcu(const struct cred *cred)
+{
+ struct key *reg_keyring = READ_ONCE(cred->user_ns->user_keyring_register);
+ key_ref_t session_keyring_r;
+ char buf[20];
+
+ struct keyring_search_context ctx = {
+ .index_key.type = &key_type_keyring,
+ .index_key.description = buf,
+ .cred = cred,
+ .match_data.cmp = key_default_cmp,
+ .match_data.raw_data = buf,
+ .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
+ .flags = KEYRING_SEARCH_DO_STATE_CHECK,
+ };
+
+ if (!reg_keyring)
+ return NULL;
+
+ ctx.index_key.desc_len = snprintf(buf, sizeof(buf), "_uid_ses.%u",
+ from_kuid(cred->user_ns,
+ cred->user->uid));
+
+ session_keyring_r = keyring_search_rcu(make_key_ref(reg_keyring, true),
+ &ctx);
+ if (IS_ERR(session_keyring_r))
+ return NULL;
+ return key_ref_to_ptr(session_keyring_r);
+}
+
/*
* Install a thread keyring to the given credentials struct if it didn't have
* one already. This is allowed to overrun the quota.
return 0;
keyring = keyring_alloc("_tid", new->uid, new->gid, new,
- KEY_POS_ALL | KEY_USR_VIEW,
+ &thread_and_process_keyring_acl,
KEY_ALLOC_QUOTA_OVERRUN,
NULL, NULL);
if (IS_ERR(keyring))
return 0;
keyring = keyring_alloc("_pid", new->uid, new->gid, new,
- KEY_POS_ALL | KEY_USR_VIEW,
+ &thread_and_process_keyring_acl,
KEY_ALLOC_QUOTA_OVERRUN,
NULL, NULL);
if (IS_ERR(keyring))
flags = KEY_ALLOC_IN_QUOTA;
keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
- KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
- flags, NULL, NULL);
+ &session_keyring_acl, flags, NULL, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
} else {
/*
* Handle the fsuid changing.
*/
-void key_fsuid_changed(struct task_struct *tsk)
+void key_fsuid_changed(struct cred *new_cred)
{
/* update the ownership of the thread keyring */
- BUG_ON(!tsk->cred);
- if (tsk->cred->thread_keyring) {
- down_write(&tsk->cred->thread_keyring->sem);
- tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
- up_write(&tsk->cred->thread_keyring->sem);
+ if (new_cred->thread_keyring) {
+ down_write(&new_cred->thread_keyring->sem);
+ new_cred->thread_keyring->uid = new_cred->fsuid;
+ up_write(&new_cred->thread_keyring->sem);
}
}
/*
* Handle the fsgid changing.
*/
-void key_fsgid_changed(struct task_struct *tsk)
+void key_fsgid_changed(struct cred *new_cred)
{
/* update the ownership of the thread keyring */
- BUG_ON(!tsk->cred);
- if (tsk->cred->thread_keyring) {
- down_write(&tsk->cred->thread_keyring->sem);
- tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
- up_write(&tsk->cred->thread_keyring->sem);
+ if (new_cred->thread_keyring) {
+ down_write(&new_cred->thread_keyring->sem);
+ new_cred->thread_keyring->gid = new_cred->fsgid;
+ up_write(&new_cred->thread_keyring->sem);
}
}
/*
* Search the process keyrings attached to the supplied cred for the first
- * matching key.
+ * matching key under RCU conditions (the caller must be holding the RCU read
+ * lock).
*
* The search criteria are the type and the match function. The description is
* given to the match function as a parameter, but doesn't otherwise influence
* In the case of a successful return, the possession attribute is set on the
* returned key reference.
*/
-key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
+key_ref_t search_cred_keyrings_rcu(struct keyring_search_context *ctx)
{
+ struct key *user_session;
key_ref_t key_ref, ret, err;
const struct cred *cred = ctx->cred;
/* search the thread keyring first */
if (cred->thread_keyring) {
- key_ref = keyring_search_aux(
+ key_ref = keyring_search_rcu(
make_key_ref(cred->thread_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
/* search the process keyring second */
if (cred->process_keyring) {
- key_ref = keyring_search_aux(
+ key_ref = keyring_search_rcu(
make_key_ref(cred->process_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
/* search the session keyring */
if (cred->session_keyring) {
- key_ref = keyring_search_aux(
+ key_ref = keyring_search_rcu(
make_key_ref(cred->session_keyring, 1), ctx);
if (!IS_ERR(key_ref))
}
}
/* or search the user-session keyring */
- else if (READ_ONCE(cred->user->session_keyring)) {
- key_ref = keyring_search_aux(
- make_key_ref(READ_ONCE(cred->user->session_keyring), 1),
- ctx);
+ else if ((user_session = get_user_session_keyring_rcu(cred))) {
+ key_ref = keyring_search_rcu(make_key_ref(user_session, 1),
+ ctx);
+ key_put(user_session);
+
if (!IS_ERR(key_ref))
goto found;
* the keys attached to the assumed authorisation key using its credentials if
* one is available.
*
- * Return same as search_my_process_keyrings().
+ * The caller must be holding the RCU read lock.
+ *
+ * Return same as search_cred_keyrings_rcu().
*/
-key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
+key_ref_t search_process_keyrings_rcu(struct keyring_search_context *ctx)
{
struct request_key_auth *rka;
key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
- might_sleep();
-
- key_ref = search_my_process_keyrings(ctx);
+ key_ref = search_cred_keyrings_rcu(ctx);
if (!IS_ERR(key_ref))
goto found;
err = key_ref;
) {
const struct cred *cred = ctx->cred;
- /* defend against the auth key being revoked */
- down_read(&cred->request_key_auth->sem);
-
- if (key_validate(ctx->cred->request_key_auth) == 0) {
+ if (key_validate(cred->request_key_auth) == 0) {
rka = ctx->cred->request_key_auth->payload.data[0];
+ //// was search_process_keyrings() [ie. recursive]
ctx->cred = rka->cred;
- key_ref = search_process_keyrings(ctx);
+ key_ref = search_cred_keyrings_rcu(ctx);
ctx->cred = cred;
- up_read(&cred->request_key_auth->sem);
-
if (!IS_ERR(key_ref))
goto found;
-
ret = key_ref;
- } else {
- up_read(&cred->request_key_auth->sem);
}
}
found:
return key_ref;
}
-
/*
* See if the key we're looking at is the target key.
*/
* returned key reference.
*/
key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
- key_perm_t perm)
+ unsigned int desired_perm)
{
struct keyring_search_context ctx = {
.match_data.cmp = lookup_user_key_possessed,
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
- .flags = KEYRING_SEARCH_NO_STATE_CHECK,
+ .flags = (KEYRING_SEARCH_NO_STATE_CHECK |
+ KEYRING_SEARCH_RECURSE),
};
struct request_key_auth *rka;
- struct key *key;
+ struct key *key, *user_session;
key_ref_t key_ref, skey_ref;
int ret;
if (!ctx.cred->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
- ret = install_user_keyrings();
+ ret = look_up_user_keyrings(NULL, &user_session);
if (ret < 0)
goto error;
if (lflags & KEY_LOOKUP_CREATE)
ret = join_session_keyring(NULL);
else
- ret = install_session_keyring(
- ctx.cred->user->session_keyring);
+ ret = install_session_keyring(user_session);
+ key_put(user_session);
if (ret < 0)
goto error;
goto reget_creds;
- } else if (ctx.cred->session_keyring ==
- READ_ONCE(ctx.cred->user->session_keyring) &&
+ } else if (test_bit(KEY_FLAG_UID_KEYRING,
+ &ctx.cred->session_keyring->flags) &&
lflags & KEY_LOOKUP_CREATE) {
ret = join_session_keyring(NULL);
if (ret < 0)
break;
case KEY_SPEC_USER_KEYRING:
- if (!READ_ONCE(ctx.cred->user->uid_keyring)) {
- ret = install_user_keyrings();
- if (ret < 0)
- goto error;
- }
-
- key = ctx.cred->user->uid_keyring;
- __key_get(key);
+ ret = look_up_user_keyrings(&key, NULL);
+ if (ret < 0)
+ goto error;
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_SESSION_KEYRING:
- if (!READ_ONCE(ctx.cred->user->session_keyring)) {
- ret = install_user_keyrings();
- if (ret < 0)
- goto error;
- }
-
- key = ctx.cred->user->session_keyring;
- __key_get(key);
+ ret = look_up_user_keyrings(NULL, &key);
+ if (ret < 0)
+ goto error;
key_ref = make_key_ref(key, 1);
break;
key_ref = make_key_ref(key, 0);
/* check to see if we possess the key */
- ctx.index_key.type = key->type;
- ctx.index_key.description = key->description;
- ctx.index_key.desc_len = strlen(key->description);
+ ctx.index_key = key->index_key;
ctx.match_data.raw_data = key;
kdebug("check possessed");
- skey_ref = search_process_keyrings(&ctx);
+ rcu_read_lock();
+ skey_ref = search_process_keyrings_rcu(&ctx);
+ rcu_read_unlock();
kdebug("possessed=%p", skey_ref);
if (!IS_ERR(skey_ref)) {
case -ERESTARTSYS:
goto invalid_key;
default:
- if (perm)
+ if (desired_perm)
goto invalid_key;
case 0:
break;
}
- } else if (perm) {
+ } else if (desired_perm) {
ret = key_validate(key);
if (ret < 0)
goto invalid_key;
goto invalid_key;
/* check the permissions */
- ret = key_task_permission(key_ref, ctx.cred, perm);
- if (ret < 0)
- goto invalid_key;
+ if (desired_perm) {
+ ret = key_task_permission(key_ref, ctx.cred, desired_perm);
+ if (ret < 0)
+ goto invalid_key;
+ }
key->last_used_at = ktime_get_real_seconds();
if (PTR_ERR(keyring) == -ENOKEY) {
/* not found - try and create a new one */
keyring = keyring_alloc(
- name, old->uid, old->gid, old,
- KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
+ name, old->uid, old->gid, old, &joinable_keyring_acl,
KEY_ALLOC_IN_QUOTA, NULL, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
}
+ goto no_perm_test;
} else if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
goto error3;
}
+ ret = key_task_permission(make_key_ref(keyring, false), old,
+ KEY_NEED_JOIN);
+ if (ret < 0)
+ goto error3;
+
+no_perm_test:
/* we've got a keyring - now to install it */
ret = install_session_keyring_to_cred(new, keyring);
if (ret < 0)
*/
static int __init init_root_keyring(void)
{
- return install_user_keyrings();
+ return look_up_user_keyrings(NULL, NULL);
}
late_initcall(init_root_keyring);
git.samba.org / sfrench / cifs-2.6.git / blobdiff