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-rw-r--r--security/keys/process_keys.c400
1 files changed, 215 insertions, 185 deletions
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 504bdd2452b..0cf8a130a26 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -1,4 +1,4 @@
-/* Management of a process's keyrings
+/* Manage a process's keyrings
*
* Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
@@ -21,41 +21,43 @@
#include <asm/uaccess.h>
#include "internal.h"
-/* session keyring create vs join semaphore */
+/* Session keyring create vs join semaphore */
static DEFINE_MUTEX(key_session_mutex);
-/* user keyring creation semaphore */
+/* User keyring creation semaphore */
static DEFINE_MUTEX(key_user_keyring_mutex);
-/* the root user's tracking struct */
+/* The root user's tracking struct */
struct key_user root_key_user = {
.usage = ATOMIC_INIT(3),
.cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
.lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
.nkeys = ATOMIC_INIT(2),
.nikeys = ATOMIC_INIT(2),
- .uid = 0,
- .user_ns = &init_user_ns,
+ .uid = GLOBAL_ROOT_UID,
};
-/*****************************************************************************/
/*
- * install user and user session keyrings for a particular UID
+ * Install the user and user session keyrings for the current process's UID.
*/
int install_user_keyrings(void)
{
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;
+ 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);
- kenter("%p{%u}", user, user->uid);
+ kenter("%p{%u}", user, uid);
- if (user->uid_keyring) {
+ if (user->uid_keyring && user->session_keyring) {
kleave(" = 0 [exist]");
return 0;
}
@@ -68,13 +70,13 @@ int install_user_keyrings(void)
* - 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", user->uid);
+ sprintf(buf, "_uid.%u", uid);
uid_keyring = find_keyring_by_name(buf, true);
if (IS_ERR(uid_keyring)) {
- uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1,
- cred, KEY_ALLOC_IN_QUOTA,
- NULL);
+ uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
+ cred, user_keyring_perm,
+ KEY_ALLOC_IN_QUOTA, NULL);
if (IS_ERR(uid_keyring)) {
ret = PTR_ERR(uid_keyring);
goto error;
@@ -83,13 +85,14 @@ int install_user_keyrings(void)
/* get a default session keyring (which might also exist
* already) */
- sprintf(buf, "_uid_ses.%u", user->uid);
+ sprintf(buf, "_uid_ses.%u", uid);
session_keyring = find_keyring_by_name(buf, true);
if (IS_ERR(session_keyring)) {
session_keyring =
- keyring_alloc(buf, user->uid, (gid_t) -1,
- cred, KEY_ALLOC_IN_QUOTA, NULL);
+ keyring_alloc(buf, user->uid, INVALID_GID,
+ cred, user_keyring_perm,
+ KEY_ALLOC_IN_QUOTA, NULL);
if (IS_ERR(session_keyring)) {
ret = PTR_ERR(session_keyring);
goto error_release;
@@ -122,13 +125,15 @@ error:
}
/*
- * install a fresh thread keyring directly to new credentials
+ * Install a fresh thread keyring directly to new credentials. This keyring is
+ * allowed to overrun the quota.
*/
int install_thread_keyring_to_cred(struct cred *new)
{
struct key *keyring;
keyring = keyring_alloc("_tid", new->uid, new->gid, new,
+ KEY_POS_ALL | KEY_USR_VIEW,
KEY_ALLOC_QUOTA_OVERRUN, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
@@ -138,7 +143,7 @@ int install_thread_keyring_to_cred(struct cred *new)
}
/*
- * install a fresh thread keyring, discarding the old one
+ * Install a fresh thread keyring, discarding the old one.
*/
static int install_thread_keyring(void)
{
@@ -161,39 +166,34 @@ static int install_thread_keyring(void)
}
/*
- * install a process keyring directly to a credentials struct
- * - returns -EEXIST if there was already a process keyring, 0 if one installed,
- * and other -ve on any other error
+ * Install a process keyring directly to a credentials struct.
+ *
+ * Returns -EEXIST if there was already a process keyring, 0 if one installed,
+ * and other value on any other error
*/
int install_process_keyring_to_cred(struct cred *new)
{
struct key *keyring;
- int ret;
- if (new->tgcred->process_keyring)
+ if (new->process_keyring)
return -EEXIST;
- keyring = keyring_alloc("_pid", new->uid, new->gid,
- new, KEY_ALLOC_QUOTA_OVERRUN, NULL);
+ keyring = keyring_alloc("_pid", new->uid, new->gid, new,
+ KEY_POS_ALL | KEY_USR_VIEW,
+ KEY_ALLOC_QUOTA_OVERRUN, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
- spin_lock_irq(&new->tgcred->lock);
- if (!new->tgcred->process_keyring) {
- new->tgcred->process_keyring = keyring;
- keyring = NULL;
- ret = 0;
- } else {
- ret = -EEXIST;
- }
- spin_unlock_irq(&new->tgcred->lock);
- key_put(keyring);
- return ret;
+ new->process_keyring = keyring;
+ return 0;
}
/*
- * make sure a process keyring is installed
- * - we
+ * Make sure a process keyring is installed for the current process. The
+ * existing process keyring is not replaced.
+ *
+ * Returns 0 if there is a process keyring by the end of this function, some
+ * error otherwise.
*/
static int install_process_keyring(void)
{
@@ -214,7 +214,7 @@ static int install_process_keyring(void)
}
/*
- * install a session keyring directly to a credentials struct
+ * Install a session keyring directly to a credentials struct.
*/
int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
{
@@ -226,36 +226,31 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
/* create an empty session keyring */
if (!keyring) {
flags = KEY_ALLOC_QUOTA_OVERRUN;
- if (cred->tgcred->session_keyring)
+ if (cred->session_keyring)
flags = KEY_ALLOC_IN_QUOTA;
- keyring = keyring_alloc("_ses", cred->uid, cred->gid,
- cred, flags, NULL);
+ keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
+ KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
+ flags, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
} else {
- atomic_inc(&keyring->usage);
+ __key_get(keyring);
}
/* install the keyring */
- spin_lock_irq(&cred->tgcred->lock);
- old = cred->tgcred->session_keyring;
- rcu_assign_pointer(cred->tgcred->session_keyring, keyring);
- spin_unlock_irq(&cred->tgcred->lock);
-
- /* we're using RCU on the pointer, but there's no point synchronising
- * on it if it didn't previously point to anything */
- if (old) {
- synchronize_rcu();
+ old = cred->session_keyring;
+ rcu_assign_pointer(cred->session_keyring, keyring);
+
+ if (old)
key_put(old);
- }
return 0;
}
/*
- * install a session keyring, discarding the old one
- * - if a keyring is not supplied, an empty one is invented
+ * Install a session keyring, discarding the old one. If a keyring is not
+ * supplied, an empty one is invented.
*/
static int install_session_keyring(struct key *keyring)
{
@@ -266,7 +261,7 @@ static int install_session_keyring(struct key *keyring)
if (!new)
return -ENOMEM;
- ret = install_session_keyring_to_cred(new, NULL);
+ ret = install_session_keyring_to_cred(new, keyring);
if (ret < 0) {
abort_creds(new);
return ret;
@@ -275,9 +270,8 @@ static int install_session_keyring(struct key *keyring)
return commit_creds(new);
}
-/*****************************************************************************/
/*
- * the filesystem user ID changed
+ * Handle the fsuid changing.
*/
void key_fsuid_changed(struct task_struct *tsk)
{
@@ -288,12 +282,10 @@ void key_fsuid_changed(struct task_struct *tsk)
tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
up_write(&tsk->cred->thread_keyring->sem);
}
+}
-} /* end key_fsuid_changed() */
-
-/*****************************************************************************/
/*
- * the filesystem group ID changed
+ * Handle the fsgid changing.
*/
void key_fsgid_changed(struct task_struct *tsk)
{
@@ -304,21 +296,30 @@ void key_fsgid_changed(struct task_struct *tsk)
tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
up_write(&tsk->cred->thread_keyring->sem);
}
+}
-} /* end key_fsgid_changed() */
-
-/*****************************************************************************/
/*
- * search only my process keyrings for the first matching key
- * - we use the supplied match function to see if the description (or other
- * feature of interest) matches
- * - we return -EAGAIN if we didn't find any matching key
- * - we return -ENOKEY if we found only negative matching keys
+ * Search the process keyrings attached to the supplied cred for the first
+ * matching key.
+ *
+ * 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
+ * the search. Typically the match function will compare the description
+ * parameter to the key's description.
+ *
+ * This can only search keyrings that grant Search permission to the supplied
+ * credentials. Keyrings linked to searched keyrings will also be searched if
+ * they grant Search permission too. Keys can only be found if they grant
+ * Search permission to the credentials.
+ *
+ * Returns a pointer to the key with the key usage count incremented if
+ * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
+ * matched negative keys.
+ *
+ * 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 key_type *type,
- const void *description,
- key_match_func_t match,
- const struct cred *cred)
+key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
{
key_ref_t key_ref, ret, err;
@@ -334,17 +335,14 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
err = ERR_PTR(-EAGAIN);
/* search the thread keyring first */
- if (cred->thread_keyring) {
+ if (ctx->cred->thread_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(cred->thread_keyring, 1),
- cred, type, description, match);
+ make_key_ref(ctx->cred->thread_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
- if (ret)
- break;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
@@ -355,10 +353,9 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
}
/* search the process keyring second */
- if (cred->tgcred->process_keyring) {
+ if (ctx->cred->process_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(cred->tgcred->process_keyring, 1),
- cred, type, description, match);
+ make_key_ref(ctx->cred->process_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
@@ -376,13 +373,11 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
}
/* search the session keyring */
- if (cred->tgcred->session_keyring) {
+ if (ctx->cred->session_keyring) {
rcu_read_lock();
key_ref = keyring_search_aux(
- make_key_ref(rcu_dereference(
- cred->tgcred->session_keyring),
- 1),
- cred, type, description, match);
+ make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
+ ctx);
rcu_read_unlock();
if (!IS_ERR(key_ref))
@@ -401,10 +396,10 @@ key_ref_t search_my_process_keyrings(struct key_type *type,
}
}
/* or search the user-session keyring */
- else if (cred->user->session_keyring) {
+ else if (ctx->cred->user->session_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(cred->user->session_keyring, 1),
- cred, type, description, match);
+ make_key_ref(ctx->cred->user->session_keyring, 1),
+ ctx);
if (!IS_ERR(key_ref))
goto found;
@@ -428,25 +423,22 @@ found:
return key_ref;
}
-/*****************************************************************************/
/*
- * search the process keyrings for the first matching key
- * - we use the supplied match function to see if the description (or other
- * feature of interest) matches
- * - we return -EAGAIN if we didn't find any matching key
- * - we return -ENOKEY if we found only negative matching keys
+ * Search the process keyrings attached to the supplied cred for the first
+ * matching key in the manner of search_my_process_keyrings(), but also search
+ * the keys attached to the assumed authorisation key using its credentials if
+ * one is available.
+ *
+ * Return same as search_my_process_keyrings().
*/
-key_ref_t search_process_keyrings(struct key_type *type,
- const void *description,
- key_match_func_t match,
- const struct cred *cred)
+key_ref_t search_process_keyrings(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(type, description, match, cred);
+ key_ref = search_my_process_keyrings(ctx);
if (!IS_ERR(key_ref))
goto found;
err = key_ref;
@@ -455,18 +447,21 @@ key_ref_t search_process_keyrings(struct key_type *type,
* search the keyrings of the process mentioned there
* - we don't permit access to request_key auth keys via this method
*/
- if (cred->request_key_auth &&
- cred == current_cred() &&
- type != &key_type_request_key_auth
+ if (ctx->cred->request_key_auth &&
+ ctx->cred == current_cred() &&
+ ctx->index_key.type != &key_type_request_key_auth
) {
+ const struct cred *cred = ctx->cred;
+
/* defend against the auth key being revoked */
down_read(&cred->request_key_auth->sem);
- if (key_validate(cred->request_key_auth) == 0) {
- rka = cred->request_key_auth->payload.data;
+ if (key_validate(ctx->cred->request_key_auth) == 0) {
+ rka = ctx->cred->request_key_auth->payload.data;
- key_ref = search_process_keyrings(type, description,
- match, rka->cred);
+ ctx->cred = rka->cred;
+ key_ref = search_process_keyrings(ctx);
+ ctx->cred = cred;
up_read(&cred->request_key_auth->sem);
@@ -489,41 +484,54 @@ key_ref_t search_process_keyrings(struct key_type *type,
found:
return key_ref;
+}
-} /* end search_process_keyrings() */
-
-/*****************************************************************************/
/*
- * see if the key we're looking at is the target key
+ * See if the key we're looking at is the target key.
*/
int lookup_user_key_possessed(const struct key *key, const void *target)
{
return key == target;
+}
-} /* end lookup_user_key_possessed() */
-
-/*****************************************************************************/
/*
- * lookup a key given a key ID from userspace with a given permissions mask
- * - don't create special keyrings unless so requested
- * - partially constructed keys aren't found unless requested
+ * Look up a key ID given us by userspace with a given permissions mask to get
+ * the key it refers to.
+ *
+ * Flags can be passed to request that special keyrings be created if referred
+ * to directly, to permit partially constructed keys to be found and to skip
+ * validity and permission checks on the found key.
+ *
+ * Returns a pointer to the key with an incremented usage count if successful;
+ * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
+ * to a key or the best found key was a negative key; -EKEYREVOKED or
+ * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
+ * found key doesn't grant the requested permit or the LSM denied access to it;
+ * or -ENOMEM if a special keyring couldn't be created.
+ *
+ * In the case of a successful return, the possession attribute is set on the
+ * returned key reference.
*/
key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
key_perm_t perm)
{
+ struct keyring_search_context ctx = {
+ .match = lookup_user_key_possessed,
+ .flags = (KEYRING_SEARCH_NO_STATE_CHECK |
+ KEYRING_SEARCH_LOOKUP_DIRECT),
+ };
struct request_key_auth *rka;
- const struct cred *cred;
struct key *key;
key_ref_t key_ref, skey_ref;
int ret;
try_again:
- cred = get_current_cred();
+ ctx.cred = get_current_cred();
key_ref = ERR_PTR(-ENOKEY);
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
- if (!cred->thread_keyring) {
+ if (!ctx.cred->thread_keyring) {
if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
@@ -535,13 +543,13 @@ try_again:
goto reget_creds;
}
- key = cred->thread_keyring;
- atomic_inc(&key->usage);
+ key = ctx.cred->thread_keyring;
+ __key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_PROCESS_KEYRING:
- if (!cred->tgcred->process_keyring) {
+ if (!ctx.cred->process_keyring) {
if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
@@ -553,54 +561,64 @@ try_again:
goto reget_creds;
}
- key = cred->tgcred->process_keyring;
- atomic_inc(&key->usage);
+ key = ctx.cred->process_keyring;
+ __key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_SESSION_KEYRING:
- if (!cred->tgcred->session_keyring) {
+ if (!ctx.cred->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = install_user_keyrings();
if (ret < 0)
goto error;
- ret = install_session_keyring(
- cred->user->session_keyring);
+ if (lflags & KEY_LOOKUP_CREATE)
+ ret = join_session_keyring(NULL);
+ else
+ ret = install_session_keyring(
+ ctx.cred->user->session_keyring);
if (ret < 0)
goto error;
goto reget_creds;
+ } else if (ctx.cred->session_keyring ==
+ ctx.cred->user->session_keyring &&
+ lflags & KEY_LOOKUP_CREATE) {
+ ret = join_session_keyring(NULL);
+ if (ret < 0)
+ goto error;
+ goto reget_creds;
}
rcu_read_lock();
- key = rcu_dereference(cred->tgcred->session_keyring);
- atomic_inc(&key->usage);
+ key = rcu_dereference(ctx.cred->session_keyring);
+ __key_get(key);
rcu_read_unlock();
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_KEYRING:
- if (!cred->user->uid_keyring) {
+ if (!ctx.cred->user->uid_keyring) {
ret = install_user_keyrings();
if (ret < 0)
goto error;
}
- key = cred->user->uid_keyring;
- atomic_inc(&key->usage);
+ key = ctx.cred->user->uid_keyring;
+ __key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_SESSION_KEYRING:
- if (!cred->user->session_keyring) {
+ if (!ctx.cred->user->session_keyring) {
ret = install_user_keyrings();
if (ret < 0)
goto error;
}
- key = cred->user->session_keyring;
- atomic_inc(&key->usage);
+ key = ctx.cred->user->session_keyring;
+ __key_get(key);
key_ref = make_key_ref(key, 1);
break;
@@ -610,28 +628,29 @@ try_again:
goto error;
case KEY_SPEC_REQKEY_AUTH_KEY:
- key = cred->request_key_auth;
+ key = ctx.cred->request_key_auth;
if (!key)
goto error;
- atomic_inc(&key->usage);
+ __key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_REQUESTOR_KEYRING:
- if (!cred->request_key_auth)
+ if (!ctx.cred->request_key_auth)
goto error;
- down_read(&cred->request_key_auth->sem);
- if (cred->request_key_auth->flags & KEY_FLAG_REVOKED) {
+ down_read(&ctx.cred->request_key_auth->sem);
+ if (test_bit(KEY_FLAG_REVOKED,
+ &ctx.cred->request_key_auth->flags)) {
key_ref = ERR_PTR(-EKEYREVOKED);
key = NULL;
} else {
- rka = cred->request_key_auth->payload.data;
+ rka = ctx.cred->request_key_auth->payload.data;
key = rka->dest_keyring;
- atomic_inc(&key->usage);
+ __key_get(key);
}
- up_read(&cred->request_key_auth->sem);
+ up_read(&ctx.cred->request_key_auth->sem);
if (!key)
goto error;
key_ref = make_key_ref(key, 1);
@@ -651,9 +670,13 @@ try_again:
key_ref = make_key_ref(key, 0);
/* check to see if we possess the key */
- skey_ref = search_process_keyrings(key->type, key,
- lookup_user_key_possessed,
- cred);
+ ctx.index_key.type = key->type;
+ ctx.index_key.description = key->description;
+ ctx.index_key.desc_len = strlen(key->description);
+ ctx.match_data = key;
+ kdebug("check possessed");
+ skey_ref = search_process_keyrings(&ctx);
+ kdebug("possessed=%p", skey_ref);
if (!IS_ERR(skey_ref)) {
key_put(key);
@@ -693,12 +716,14 @@ try_again:
goto invalid_key;
/* check the permissions */
- ret = key_task_permission(key_ref, cred, perm);
+ ret = key_task_permission(key_ref, ctx.cred, perm);
if (ret < 0)
goto invalid_key;
+ key->last_used_at = current_kernel_time().tv_sec;
+
error:
- put_cred(cred);
+ put_cred(ctx.cred);
return key_ref;
invalid_key:
@@ -709,17 +734,20 @@ invalid_key:
/* if we attempted to install a keyring, then it may have caused new
* creds to be installed */
reget_creds:
- put_cred(cred);
+ put_cred(ctx.cred);
goto try_again;
+}
-} /* end lookup_user_key() */
-
-/*****************************************************************************/
/*
- * join the named keyring as the session keyring if possible, or attempt to
- * create a new one of that name if not
- * - if the name is NULL, an empty anonymous keyring is installed instead
- * - named session keyring joining is done with a semaphore held
+ * Join the named keyring as the session keyring if possible else attempt to
+ * create a new one of that name and join that.
+ *
+ * If the name is NULL, an empty anonymous keyring will be installed as the
+ * session keyring.
+ *
+ * Named session keyrings are joined with a semaphore held to prevent the
+ * keyrings from going away whilst the attempt is made to going them and also
+ * to prevent a race in creating compatible session keyrings.
*/
long join_session_keyring(const char *name)
{
@@ -728,12 +756,6 @@ long join_session_keyring(const char *name)
struct key *keyring;
long ret, serial;
- /* only permit this if there's a single thread in the thread group -
- * this avoids us having to adjust the creds on all threads and risking
- * ENOMEM */
- if (!current_is_single_threaded())
- return -EMLINK;
-
new = prepare_creds();
if (!new)
return -ENOMEM;
@@ -745,7 +767,7 @@ long join_session_keyring(const char *name)
if (ret < 0)
goto error;
- serial = new->tgcred->session_keyring->serial;
+ serial = new->session_keyring->serial;
ret = commit_creds(new);
if (ret == 0)
ret = serial;
@@ -759,8 +781,10 @@ long join_session_keyring(const char *name)
keyring = find_keyring_by_name(name, false);
if (PTR_ERR(keyring) == -ENOKEY) {
/* not found - try and create a new one */
- keyring = keyring_alloc(name, old->uid, old->gid, old,
- KEY_ALLOC_IN_QUOTA, NULL);
+ keyring = keyring_alloc(
+ name, old->uid, old->gid, old,
+ KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
+ KEY_ALLOC_IN_QUOTA, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
@@ -768,6 +792,9 @@ long join_session_keyring(const char *name)
} else if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
+ } else if (keyring == new->session_keyring) {
+ ret = 0;
+ goto error2;
}
/* we've got a keyring - now to install it */
@@ -791,26 +818,19 @@ error:
}
/*
- * Replace a process's session keyring when that process resumes userspace on
- * behalf of one of its children
+ * Replace a process's session keyring on behalf of one of its children when
+ * the target process is about to resume userspace execution.
*/
-void key_replace_session_keyring(void)
+void key_change_session_keyring(struct callback_head *twork)
{
- const struct cred *old;
- struct cred *new;
+ const struct cred *old = current_cred();
+ struct cred *new = container_of(twork, struct cred, rcu);
- if (!current->replacement_session_keyring)
- return;
-
- write_lock_irq(&tasklist_lock);
- new = current->replacement_session_keyring;
- current->replacement_session_keyring = NULL;
- write_unlock_irq(&tasklist_lock);
-
- if (!new)
+ if (unlikely(current->flags & PF_EXITING)) {
+ put_cred(new);
return;
+ }
- old = current_cred();
new-> uid = old-> uid;
new-> euid = old-> euid;
new-> suid = old-> suid;
@@ -820,6 +840,7 @@ void key_replace_session_keyring(void)
new-> sgid = old-> sgid;
new->fsgid = old->fsgid;
new->user = get_uid(old->user);
+ new->user_ns = get_user_ns(old->user_ns);
new->group_info = get_group_info(old->group_info);
new->securebits = old->securebits;
@@ -830,10 +851,19 @@ void key_replace_session_keyring(void)
new->jit_keyring = old->jit_keyring;
new->thread_keyring = key_get(old->thread_keyring);
- new->tgcred->tgid = old->tgcred->tgid;
- new->tgcred->process_keyring = key_get(old->tgcred->process_keyring);
+ new->process_keyring = key_get(old->process_keyring);
security_transfer_creds(new, old);
commit_creds(new);
}
+
+/*
+ * Make sure that root's user and user-session keyrings exist.
+ */
+static int __init init_root_keyring(void)
+{
+ return install_user_keyrings();
+}
+
+late_initcall(init_root_keyring);