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-rw-r--r--security/keys/key.c94
-rw-r--r--security/keys/keyctl.c23
-rw-r--r--security/keys/keyring.c245
-rw-r--r--security/keys/proc.c21
-rw-r--r--security/keys/process_keys.c12
-rw-r--r--security/keys/request_key.c32
-rw-r--r--security/keys/user_defined.c85
7 files changed, 289 insertions, 223 deletions
diff --git a/security/keys/key.c b/security/keys/key.c
index 59402c84320..1fdfccb3fe4 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -294,7 +294,6 @@ struct key *key_alloc(struct key_type *type, const char *desc,
}
atomic_set(&key->usage, 1);
- rwlock_init(&key->lock);
init_rwsem(&key->sem);
key->type = type;
key->user = user;
@@ -308,7 +307,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
key->payload.data = NULL;
if (!not_in_quota)
- key->flags |= KEY_FLAG_IN_QUOTA;
+ key->flags |= 1 << KEY_FLAG_IN_QUOTA;
memset(&key->type_data, 0, sizeof(key->type_data));
@@ -359,7 +358,7 @@ int key_payload_reserve(struct key *key, size_t datalen)
key_check(key);
/* contemplate the quota adjustment */
- if (delta != 0 && key->flags & KEY_FLAG_IN_QUOTA) {
+ if (delta != 0 && test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
spin_lock(&key->user->lock);
if (delta > 0 &&
@@ -405,23 +404,17 @@ static int __key_instantiate_and_link(struct key *key,
down_write(&key_construction_sem);
/* can't instantiate twice */
- if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
+ if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
/* instantiate the key */
ret = key->type->instantiate(key, data, datalen);
if (ret == 0) {
/* mark the key as being instantiated */
- write_lock(&key->lock);
-
atomic_inc(&key->user->nikeys);
- key->flags |= KEY_FLAG_INSTANTIATED;
+ set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
- if (key->flags & KEY_FLAG_USER_CONSTRUCT) {
- key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
+ if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
awaken = 1;
- }
-
- write_unlock(&key->lock);
/* and link it into the destination keyring */
if (keyring)
@@ -486,21 +479,17 @@ int key_negate_and_link(struct key *key,
down_write(&key_construction_sem);
/* can't instantiate twice */
- if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
+ if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
/* mark the key as being negatively instantiated */
- write_lock(&key->lock);
-
atomic_inc(&key->user->nikeys);
- key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE;
+ set_bit(KEY_FLAG_NEGATIVE, &key->flags);
+ set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
now = current_kernel_time();
key->expiry = now.tv_sec + timeout;
- if (key->flags & KEY_FLAG_USER_CONSTRUCT) {
- key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
+ if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
awaken = 1;
- }
- write_unlock(&key->lock);
ret = 0;
/* and link it into the destination keyring */
@@ -553,8 +542,10 @@ static void key_cleanup(void *data)
rb_erase(&key->serial_node, &key_serial_tree);
spin_unlock(&key_serial_lock);
+ key_check(key);
+
/* deal with the user's key tracking and quota */
- if (key->flags & KEY_FLAG_IN_QUOTA) {
+ if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
spin_lock(&key->user->lock);
key->user->qnkeys--;
key->user->qnbytes -= key->quotalen;
@@ -562,7 +553,7 @@ static void key_cleanup(void *data)
}
atomic_dec(&key->user->nkeys);
- if (key->flags & KEY_FLAG_INSTANTIATED)
+ if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
atomic_dec(&key->user->nikeys);
key_user_put(key->user);
@@ -631,9 +622,9 @@ struct key *key_lookup(key_serial_t id)
goto error;
found:
- /* pretent doesn't exist if it's dead */
+ /* pretend it doesn't exist if it's dead */
if (atomic_read(&key->usage) == 0 ||
- (key->flags & KEY_FLAG_DEAD) ||
+ test_bit(KEY_FLAG_DEAD, &key->flags) ||
key->type == &key_type_dead)
goto not_found;
@@ -708,12 +699,9 @@ static inline struct key *__key_update(struct key *key, const void *payload,
ret = key->type->update(key, payload, plen);
- if (ret == 0) {
+ if (ret == 0)
/* updating a negative key instantiates it */
- write_lock(&key->lock);
- key->flags &= ~KEY_FLAG_NEGATIVE;
- write_unlock(&key->lock);
- }
+ clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
up_write(&key->sem);
@@ -841,12 +829,9 @@ int key_update(struct key *key, const void *payload, size_t plen)
down_write(&key->sem);
ret = key->type->update(key, payload, plen);
- if (ret == 0) {
+ if (ret == 0)
/* updating a negative key instantiates it */
- write_lock(&key->lock);
- key->flags &= ~KEY_FLAG_NEGATIVE;
- write_unlock(&key->lock);
- }
+ clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
up_write(&key->sem);
}
@@ -892,10 +877,7 @@ struct key *key_duplicate(struct key *source, const char *desc)
goto error2;
atomic_inc(&key->user->nikeys);
-
- write_lock(&key->lock);
- key->flags |= KEY_FLAG_INSTANTIATED;
- write_unlock(&key->lock);
+ set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
error_k:
up_read(&key_types_sem);
@@ -922,9 +904,7 @@ void key_revoke(struct key *key)
/* make sure no one's trying to change or use the key when we mark
* it */
down_write(&key->sem);
- write_lock(&key->lock);
- key->flags |= KEY_FLAG_REVOKED;
- write_unlock(&key->lock);
+ set_bit(KEY_FLAG_REVOKED, &key->flags);
up_write(&key->sem);
} /* end key_revoke() */
@@ -975,24 +955,33 @@ void unregister_key_type(struct key_type *ktype)
/* withdraw the key type */
list_del_init(&ktype->link);
- /* need to withdraw all keys of this type */
+ /* mark all the keys of this type dead */
spin_lock(&key_serial_lock);
for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
key = rb_entry(_n, struct key, serial_node);
- if (key->type != ktype)
- continue;
+ if (key->type == ktype)
+ key->type = &key_type_dead;
+ }
+
+ spin_unlock(&key_serial_lock);
+
+ /* make sure everyone revalidates their keys */
+ synchronize_kernel();
+
+ /* we should now be able to destroy the payloads of all the keys of
+ * this type with impunity */
+ spin_lock(&key_serial_lock);
- write_lock(&key->lock);
- key->type = &key_type_dead;
- write_unlock(&key->lock);
+ for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
+ key = rb_entry(_n, struct key, serial_node);
- /* there shouldn't be anyone looking at the description or
- * payload now */
- if (ktype->destroy)
- ktype->destroy(key);
- memset(&key->payload, 0xbd, sizeof(key->payload));
+ if (key->type == ktype) {
+ if (ktype->destroy)
+ ktype->destroy(key);
+ memset(&key->payload, 0xbd, sizeof(key->payload));
+ }
}
spin_unlock(&key_serial_lock);
@@ -1037,4 +1026,5 @@ void __init key_init(void)
/* link the two root keyrings together */
key_link(&root_session_keyring, &root_user_keyring);
+
} /* end key_init() */
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index dc0011b3fac..cedb7326de2 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -728,7 +728,6 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
/* make the changes with the locks held to prevent chown/chown races */
ret = -EACCES;
down_write(&key->sem);
- write_lock(&key->lock);
if (!capable(CAP_SYS_ADMIN)) {
/* only the sysadmin can chown a key to some other UID */
@@ -755,7 +754,6 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
ret = 0;
no_access:
- write_unlock(&key->lock);
up_write(&key->sem);
key_put(key);
error:
@@ -784,26 +782,19 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
goto error;
}
- /* make the changes with the locks held to prevent chown/chmod
- * races */
+ /* make the changes with the locks held to prevent chown/chmod races */
ret = -EACCES;
down_write(&key->sem);
- write_lock(&key->lock);
- /* if we're not the sysadmin, we can only chmod a key that we
- * own */
- if (!capable(CAP_SYS_ADMIN) && key->uid != current->fsuid)
- goto no_access;
-
- /* changing the permissions mask */
- key->perm = perm;
- ret = 0;
+ /* if we're not the sysadmin, we can only change a key that we own */
+ if (capable(CAP_SYS_ADMIN) || key->uid == current->fsuid) {
+ key->perm = perm;
+ ret = 0;
+ }
- no_access:
- write_unlock(&key->lock);
up_write(&key->sem);
key_put(key);
- error:
+error:
return ret;
} /* end keyctl_setperm_key() */
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index e2ab4f8e748..c9a5de19748 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -132,10 +132,17 @@ static int keyring_duplicate(struct key *keyring, const struct key *source)
(PAGE_SIZE - sizeof(*klist)) / sizeof(struct key);
ret = 0;
- sklist = source->payload.subscriptions;
- if (sklist && sklist->nkeys > 0) {
+ /* find out how many keys are currently linked */
+ rcu_read_lock();
+ sklist = rcu_dereference(source->payload.subscriptions);
+ max = 0;
+ if (sklist)
max = sklist->nkeys;
+ rcu_read_unlock();
+
+ /* allocate a new payload and stuff load with key links */
+ if (max > 0) {
BUG_ON(max > limit);
max = (max + 3) & ~3;
@@ -148,6 +155,10 @@ static int keyring_duplicate(struct key *keyring, const struct key *source)
if (!klist)
goto error;
+ /* set links */
+ rcu_read_lock();
+ sklist = rcu_dereference(source->payload.subscriptions);
+
klist->maxkeys = max;
klist->nkeys = sklist->nkeys;
memcpy(klist->keys,
@@ -157,7 +168,9 @@ static int keyring_duplicate(struct key *keyring, const struct key *source)
for (loop = klist->nkeys - 1; loop >= 0; loop--)
atomic_inc(&klist->keys[loop]->usage);
- keyring->payload.subscriptions = klist;
+ rcu_read_unlock();
+
+ rcu_assign_pointer(keyring->payload.subscriptions, klist);
ret = 0;
}
@@ -192,7 +205,7 @@ static void keyring_destroy(struct key *keyring)
write_unlock(&keyring_name_lock);
}
- klist = keyring->payload.subscriptions;
+ klist = rcu_dereference(keyring->payload.subscriptions);
if (klist) {
for (loop = klist->nkeys - 1; loop >= 0; loop--)
key_put(klist->keys[loop]);
@@ -216,17 +229,20 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m)
seq_puts(m, "[anon]");
}
- klist = keyring->payload.subscriptions;
+ rcu_read_lock();
+ klist = rcu_dereference(keyring->payload.subscriptions);
if (klist)
seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys);
else
seq_puts(m, ": empty");
+ rcu_read_unlock();
} /* end keyring_describe() */
/*****************************************************************************/
/*
* read a list of key IDs from the keyring's contents
+ * - the keyring's semaphore is read-locked
*/
static long keyring_read(const struct key *keyring,
char __user *buffer, size_t buflen)
@@ -237,7 +253,7 @@ static long keyring_read(const struct key *keyring,
int loop, ret;
ret = 0;
- klist = keyring->payload.subscriptions;
+ klist = rcu_dereference(keyring->payload.subscriptions);
if (klist) {
/* calculate how much data we could return */
@@ -320,7 +336,7 @@ struct key *keyring_search_aux(struct key *keyring,
key_match_func_t match)
{
struct {
- struct key *keyring;
+ struct keyring_list *keylist;
int kix;
} stack[KEYRING_SEARCH_MAX_DEPTH];
@@ -328,10 +344,12 @@ struct key *keyring_search_aux(struct key *keyring,
struct timespec now;
struct key *key;
long err;
- int sp, psp, kix;
+ int sp, kix;
key_check(keyring);
+ rcu_read_lock();
+
/* top keyring must have search permission to begin the search */
key = ERR_PTR(-EACCES);
if (!key_permission(keyring, KEY_SEARCH))
@@ -347,11 +365,10 @@ struct key *keyring_search_aux(struct key *keyring,
/* start processing a new keyring */
descend:
- read_lock(&keyring->lock);
- if (keyring->flags & KEY_FLAG_REVOKED)
+ if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
goto not_this_keyring;
- keylist = keyring->payload.subscriptions;
+ keylist = rcu_dereference(keyring->payload.subscriptions);
if (!keylist)
goto not_this_keyring;
@@ -364,7 +381,7 @@ struct key *keyring_search_aux(struct key *keyring,
continue;
/* skip revoked keys and expired keys */
- if (key->flags & KEY_FLAG_REVOKED)
+ if (test_bit(KEY_FLAG_REVOKED, &key->flags))
continue;
if (key->expiry && now.tv_sec >= key->expiry)
@@ -379,7 +396,7 @@ struct key *keyring_search_aux(struct key *keyring,
continue;
/* we set a different error code if we find a negative key */
- if (key->flags & KEY_FLAG_NEGATIVE) {
+ if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
err = -ENOKEY;
continue;
}
@@ -390,48 +407,37 @@ struct key *keyring_search_aux(struct key *keyring,
/* search through the keyrings nested in this one */
kix = 0;
ascend:
- while (kix < keylist->nkeys) {
+ for (; kix < keylist->nkeys; kix++) {
key = keylist->keys[kix];
if (key->type != &key_type_keyring)
- goto next;
+ continue;
/* recursively search nested keyrings
* - only search keyrings for which we have search permission
*/
if (sp >= KEYRING_SEARCH_MAX_DEPTH)
- goto next;
+ continue;
if (!key_permission(key, KEY_SEARCH))
- goto next;
-
- /* evade loops in the keyring tree */
- for (psp = 0; psp < sp; psp++)
- if (stack[psp].keyring == keyring)
- goto next;
+ continue;
/* stack the current position */
- stack[sp].keyring = keyring;
+ stack[sp].keylist = keylist;
stack[sp].kix = kix;
sp++;
/* begin again with the new keyring */
keyring = key;
goto descend;
-
- next:
- kix++;
}
/* the keyring we're looking at was disqualified or didn't contain a
* matching key */
not_this_keyring:
- read_unlock(&keyring->lock);
-
if (sp > 0) {
/* resume the processing of a keyring higher up in the tree */
sp--;
- keyring = stack[sp].keyring;
- keylist = keyring->payload.subscriptions;
+ keylist = stack[sp].keylist;
kix = stack[sp].kix + 1;
goto ascend;
}
@@ -442,16 +448,9 @@ struct key *keyring_search_aux(struct key *keyring,
/* we found a viable match */
found:
atomic_inc(&key->usage);
- read_unlock(&keyring->lock);
-
- /* unwind the keyring stack */
- while (sp > 0) {
- sp--;
- read_unlock(&stack[sp].keyring->lock);
- }
-
key_check(key);
error:
+ rcu_read_unlock();
return key;
} /* end keyring_search_aux() */
@@ -489,7 +488,9 @@ struct key *__keyring_search_one(struct key *keyring,
struct key *key;
int loop;
- klist = keyring->payload.subscriptions;
+ rcu_read_lock();
+
+ klist = rcu_dereference(keyring->payload.subscriptions);
if (klist) {
for (loop = 0; loop < klist->nkeys; loop++) {
key = klist->keys[loop];
@@ -497,7 +498,7 @@ struct key *__keyring_search_one(struct key *keyring,
if (key->type == ktype &&
key->type->match(key, description) &&
key_permission(key, perm) &&
- !(key->flags & KEY_FLAG_REVOKED)
+ !test_bit(KEY_FLAG_REVOKED, &key->flags)
)
goto found;
}
@@ -509,6 +510,7 @@ struct key *__keyring_search_one(struct key *keyring,
found:
atomic_inc(&key->usage);
error:
+ rcu_read_unlock();
return key;
} /* end __keyring_search_one() */
@@ -540,7 +542,7 @@ struct key *find_keyring_by_name(const char *name, key_serial_t bound)
&keyring_name_hash[bucket],
type_data.link
) {
- if (keyring->flags & KEY_FLAG_REVOKED)
+ if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
continue;
if (strcmp(keyring->description, name) != 0)
@@ -579,7 +581,7 @@ struct key *find_keyring_by_name(const char *name, key_serial_t bound)
static int keyring_detect_cycle(struct key *A, struct key *B)
{
struct {
- struct key *subtree;
+ struct keyring_list *keylist;
int kix;
} stack[KEYRING_SEARCH_MAX_DEPTH];
@@ -587,20 +589,21 @@ static int keyring_detect_cycle(struct key *A, struct key *B)
struct key *subtree, *key;
int sp, kix, ret;
+ rcu_read_lock();
+
ret = -EDEADLK;
if (A == B)
- goto error;
+ goto cycle_detected;
subtree = B;
sp = 0;
/* start processing a new keyring */
descend:
- read_lock(&subtree->lock);
- if (subtree->flags & KEY_FLAG_REVOKED)
+ if (test_bit(KEY_FLAG_REVOKED, &subtree->flags))
goto not_this_keyring;
- keylist = subtree->payload.subscriptions;
+ keylist = rcu_dereference(subtree->payload.subscriptions);
if (!keylist)
goto not_this_keyring;
kix = 0;
@@ -619,7 +622,7 @@ static int keyring_detect_cycle(struct key *A, struct key *B)
goto too_deep;
/* stack the current position */
- stack[sp].subtree = subtree;
+ stack[sp].keylist = keylist;
stack[sp].kix = kix;
sp++;
@@ -632,13 +635,10 @@ static int keyring_detect_cycle(struct key *A, struct key *B)
/* the keyring we're looking at was disqualified or didn't contain a
* matching key */
not_this_keyring:
- read_unlock(&subtree->lock);
-
if (sp > 0) {
/* resume the checking of a keyring higher up in the tree */
sp--;
- subtree = stack[sp].subtree;
- keylist = subtree->payload.subscriptions;
+ keylist = stack[sp].keylist;
kix = stack[sp].kix + 1;
goto ascend;
}
@@ -646,30 +646,36 @@ static int keyring_detect_cycle(struct key *A, struct key *B)
ret = 0; /* no cycles detected */
error:
+ rcu_read_unlock();
return ret;
too_deep:
ret = -ELOOP;
- goto error_unwind;
+ goto error;
+
cycle_detected:
ret = -EDEADLK;
- error_unwind:
- read_unlock(&subtree->lock);
-
- /* unwind the keyring stack */
- while (sp > 0) {
- sp--;
- read_unlock(&stack[sp].subtree->lock);
- }
-
goto error;
} /* end keyring_detect_cycle() */
/*****************************************************************************/
/*
+ * dispose of a keyring list after the RCU grace period
+ */
+static void keyring_link_rcu_disposal(struct rcu_head *rcu)
+{
+ struct keyring_list *klist =
+ container_of(rcu, struct keyring_list, rcu);
+
+ kfree(klist);
+
+} /* end keyring_link_rcu_disposal() */
+
+/*****************************************************************************/
+/*
* link a key into to a keyring
- * - must be called with the keyring's semaphore held
+ * - must be called with the keyring's semaphore write-locked
*/
int __key_link(struct key *keyring, struct key *key)
{
@@ -679,7 +685,7 @@ int __key_link(struct key *keyring, struct key *key)
int ret;
ret = -EKEYREVOKED;
- if (keyring->flags & KEY_FLAG_REVOKED)
+ if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
goto error;
ret = -ENOTDIR;
@@ -710,9 +716,10 @@ int __key_link(struct key *keyring, struct key *key)
/* there's sufficient slack space to add directly */
atomic_inc(&key->usage);
- write_lock(&keyring->lock);
- klist->keys[klist->nkeys++] = key;
- write_unlock(&keyring->lock);
+ klist->keys[klist->nkeys] = key;
+ smp_wmb();
+ klist->nkeys++;
+ smp_wmb();
ret = 0;
}
@@ -723,6 +730,8 @@ int __key_link(struct key *keyring, struct key *key)
max += klist->maxkeys;
ret = -ENFILE;
+ if (max > 65535)
+ goto error3;
size = sizeof(*klist) + sizeof(*key) * max;
if (size > PAGE_SIZE)
goto error3;
@@ -743,14 +752,13 @@ int __key_link(struct key *keyring, struct key *key)
/* add the key into the new space */
atomic_inc(&key->usage);
-
- write_lock(&keyring->lock);
- keyring->payload.subscriptions = nklist;
nklist->keys[nklist->nkeys++] = key;
- write_unlock(&keyring->lock);
+
+ rcu_assign_pointer(keyring->payload.subscriptions, nklist);
/* dispose of the old keyring list */
- kfree(klist);
+ if (klist)
+ call_rcu(&klist->rcu, keyring_link_rcu_disposal);
ret = 0;
}
@@ -791,11 +799,26 @@ EXPORT_SYMBOL(key_link);
/*****************************************************************************/
/*
+ * dispose of a keyring list after the RCU grace period, freeing the unlinked
+ * key
+ */
+static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
+{
+ struct keyring_list *klist =
+ container_of(rcu, struct keyring_list, rcu);
+
+ key_put(klist->keys[klist->delkey]);
+ kfree(klist);
+
+} /* end keyring_unlink_rcu_disposal() */
+
+/*****************************************************************************/
+/*
* unlink the first link to a key from a keyring
*/
int key_unlink(struct key *keyring, struct key *key)
{
- struct keyring_list *klist;
+ struct keyring_list *klist, *nklist;
int loop, ret;
key_check(keyring);
@@ -819,31 +842,45 @@ int key_unlink(struct key *keyring, struct key *key)
ret = -ENOENT;
goto error;
- key_is_present:
+key_is_present:
+ /* we need to copy the key list for RCU purposes */
+ nklist = kmalloc(sizeof(*klist) + sizeof(*key) * klist->maxkeys,
+ GFP_KERNEL);
+ if (!nklist)
+ goto nomem;
+ nklist->maxkeys = klist->maxkeys;
+ nklist->nkeys = klist->nkeys - 1;
+
+ if (loop > 0)
+ memcpy(&nklist->keys[0],
+ &klist->keys[0],
+ loop * sizeof(klist->keys[0]));
+
+ if (loop < nklist->nkeys)
+ memcpy(&nklist->keys[loop],
+ &klist->keys[loop + 1],
+ (nklist->nkeys - loop) * sizeof(klist->keys[0]));
+
/* adjust the user's quota */
key_payload_reserve(keyring,
keyring->datalen - KEYQUOTA_LINK_BYTES);
- /* shuffle down the key pointers
- * - it might be worth shrinking the allocated memory, but that runs
- * the risk of ENOMEM as we would have to copy
- */
- write_lock(&keyring->lock);
+ rcu_assign_pointer(keyring->payload.subscriptions, nklist);
- klist->nkeys--;
- if (loop < klist->nkeys)
- memcpy(&klist->keys[loop],
- &klist->keys[loop + 1],
- (klist->nkeys - loop) * sizeof(struct key *));
+ up_write(&keyring->sem);
- write_unlock(&keyring->lock);
+ /* schedule for later cleanup */
+ klist->delkey = loop;
+ call_rcu(&klist->rcu, keyring_unlink_rcu_disposal);
- up_write(&keyring->sem);
- key_put(key);
ret = 0;
- error:
+error:
return ret;
+nomem:
+ ret = -ENOMEM;
+ up_write(&keyring->sem);
+ goto error;
} /* end key_unlink() */
@@ -851,13 +888,32 @@ EXPORT_SYMBOL(key_unlink);
/*****************************************************************************/
/*
+ * dispose of a keyring list after the RCU grace period, releasing the keys it
+ * links to
+ */
+static void keyring_clear_rcu_disposal(struct rcu_head *rcu)
+{
+ struct keyring_list *klist;
+ int loop;
+
+ klist = container_of(rcu, struct keyring_list, rcu);
+
+ for (loop = klist->nkeys - 1; loop >= 0; loop--)
+ key_put(klist->keys[loop]);
+
+ kfree(klist);
+
+} /* end keyring_clear_rcu_disposal() */
+
+/*****************************************************************************/
+/*
* clear the specified process keyring
* - implements keyctl(KEYCTL_CLEAR)
*/
int keyring_clear(struct key *keyring)
{
struct keyring_list *klist;
- int loop, ret;
+ int ret;
ret = -ENOTDIR;
if (keyring->type == &key_type_keyring) {
@@ -870,20 +926,15 @@ int keyring_clear(struct key *keyring)
key_payload_reserve(keyring,
sizeof(struct keyring_list));
- write_lock(&keyring->lock);
- keyring->payload.subscriptions = NULL;
- write_unlock(&keyring->lock);
+ rcu_assign_pointer(keyring->payload.subscriptions,
+ NULL);
}
up_write(&keyring->sem);
/* free the keys after the locks have been dropped */
- if (klist) {
- for (loop = klist->nkeys - 1; loop >= 0; loop--)
- key_put(klist->keys[loop]);
-
- kfree(klist);
- }
+ if (klist)
+ call_rcu(&klist->rcu, keyring_clear_rcu_disposal);
ret = 0;
}
diff --git a/security/keys/proc.c b/security/keys/proc.c
index 91343b85c39..c55cf1fd082 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -140,7 +140,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
now = current_kernel_time();
- read_lock(&key->lock);
+ rcu_read_lock();
/* come up with a suitable timeout value */
if (key->expiry == 0) {
@@ -164,14 +164,17 @@ static int proc_keys_show(struct seq_file *m, void *v)
sprintf(xbuf, "%luw", timo / (60*60*24*7));
}
+#define showflag(KEY, LETTER, FLAG) \
+ (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-')
+
seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %06x %5d %5d %-9.9s ",
key->serial,
- key->flags & KEY_FLAG_INSTANTIATED ? 'I' : '-',
- key->flags & KEY_FLAG_REVOKED ? 'R' : '-',
- key->flags & KEY_FLAG_DEAD ? 'D' : '-',
- key->flags & KEY_FLAG_IN_QUOTA ? 'Q' : '-',
- key->flags & KEY_FLAG_USER_CONSTRUCT ? 'U' : '-',
- key->flags & KEY_FLAG_NEGATIVE ? 'N' : '-',
+ showflag(key, 'I', KEY_FLAG_INSTANTIATED),
+ showflag(key, 'R', KEY_FLAG_REVOKED),
+ showflag(key, 'D', KEY_FLAG_DEAD),
+ showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
+ showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
+ showflag(key, 'N', KEY_FLAG_NEGATIVE),
atomic_read(&key->usage),
xbuf,
key->perm,
@@ -179,11 +182,13 @@ static int proc_keys_show(struct seq_file *m, void *v)
key->gid,
key->type->name);
+#undef showflag
+
if (key->type->describe)
key->type->describe(key, m);
seq_putc(m, '\n');
- read_unlock(&key->lock);
+ rcu_read_unlock();
return 0;
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 2eb0e471cd4..059c350cac4 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -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,
@@ -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);
}
@@ -588,7 +582,7 @@ 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;
ret = -EACCES;
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 9705b1aeba5..1f6c0940297 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -105,7 +105,7 @@ static struct key *__request_key_construction(struct key_type *type,
struct key_construction cons;
struct timespec now;
struct key *key;
- int ret, negative;
+ int ret, negated;
/* create a key and add it to the queue */
key = key_alloc(type, description,
@@ -113,9 +113,7 @@ static struct key *__request_key_construction(struct key_type *type,
if (IS_ERR(key))
goto alloc_failed;
- write_lock(&key->lock);
- key->flags |= KEY_FLAG_USER_CONSTRUCT;
- write_unlock(&key->lock);
+ set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
cons.key = key;
list_add_tail(&cons.link, &key->user->consq);
@@ -130,7 +128,7 @@ static struct key *__request_key_construction(struct key_type *type,
/* if the key wasn't instantiated, then we want to give an error */
ret = -ENOKEY;
- if (!(key->flags & KEY_FLAG_INSTANTIATED))
+ if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto request_failed;
down_write(&key_construction_sem);
@@ -139,7 +137,7 @@ static struct key *__request_key_construction(struct key_type *type,
/* also give an error if the key was negatively instantiated */
check_not_negative:
- if (key->flags & KEY_FLAG_NEGATIVE) {
+ if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
key_put(key);
key = ERR_PTR(-ENOKEY);
}
@@ -152,24 +150,23 @@ static struct key *__request_key_construction(struct key_type *type,
* - remove from construction queue
* - mark the key as dead
*/
- negative = 0;
+ negated = 0;
down_write(&key_construction_sem);
list_del(&cons.link);
- write_lock(&key->lock);
- key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
-
/* check it didn't get instantiated between the check and the down */
- if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
- key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE;
- negative = 1;
+ if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
+ set_bit(KEY_FLAG_NEGATIVE, &key->flags);
+ set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
+ negated = 1;
}
- write_unlock(&key->lock);
+ clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
+
up_write(&key_construction_sem);
- if (!negative)
+ if (!negated)
goto check_not_negative; /* surprisingly, the key got
* instantiated */
@@ -250,7 +247,7 @@ static struct key *request_key_construction(struct key_type *type,
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
- if (!(ckey->flags & KEY_FLAG_USER_CONSTRUCT))
+ if (!test_bit(KEY_FLAG_USER_CONSTRUCT, &ckey->flags))
break;
schedule();
}
@@ -339,7 +336,8 @@ int key_validate(struct key *key)
if (key) {
/* check it's still accessible */
ret = -EKEYREVOKED;
- if (key->flags & (KEY_FLAG_REVOKED | KEY_FLAG_DEAD))
+ if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
+ test_bit(KEY_FLAG_DEAD, &key->flags))
goto error;
/* check it hasn't expired */
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 8d65b3a2812..c33d3614a0d 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -42,12 +42,19 @@ struct key_type key_type_user = {
.read = user_read,
};
+struct user_key_payload {
+ struct rcu_head rcu; /* RCU destructor */
+ unsigned short datalen; /* length of this data */
+ char data[0]; /* actual data */
+};
+
/*****************************************************************************/
/*
* instantiate a user defined key
*/
static int user_instantiate(struct key *key, const void *data, size_t datalen)
{
+ struct user_key_payload *upayload;
int ret;
ret = -EINVAL;
@@ -58,13 +65,15 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen)
if (ret < 0)
goto error;
- /* attach the data */
ret = -ENOMEM;
- key->payload.data = kmalloc(datalen, GFP_KERNEL);
- if (!key->payload.data)
+ upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+ if (!upayload)
goto error;
- memcpy(key->payload.data, data, datalen);
+ /* attach the data */
+ upayload->datalen = datalen;
+ memcpy(upayload->data, data, datalen);
+ rcu_assign_pointer(key->payload.data, upayload);
ret = 0;
error:
@@ -75,18 +84,25 @@ static int user_instantiate(struct key *key, const void *data, size_t datalen)
/*****************************************************************************/
/*
* duplicate a user defined key
+ * - both keys' semaphores are locked against further modification
+ * - the new key cannot yet be accessed
*/
static int user_duplicate(struct key *key, const struct key *source)
{
+ struct user_key_payload *upayload, *spayload;
int ret;
/* just copy the payload */
ret = -ENOMEM;
- key->payload.data = kmalloc(source->datalen, GFP_KERNEL);
+ upayload = kmalloc(sizeof(*upayload) + source->datalen, GFP_KERNEL);
+ if (upayload) {
+ spayload = rcu_dereference(source->payload.data);
+ BUG_ON(source->datalen != spayload->datalen);
- if (key->payload.data) {
- key->datalen = source->datalen;
- memcpy(key->payload.data, source->payload.data, source->datalen);
+ upayload->datalen = key->datalen = spayload->datalen;
+ memcpy(upayload->data, spayload->data, key->datalen);
+
+ key->payload.data = upayload;
ret = 0;
}
@@ -96,40 +112,54 @@ static int user_duplicate(struct key *key, const struct key *source)
/*****************************************************************************/
/*
+ * dispose of the old data from an updated user defined key
+ */
+static void user_update_rcu_disposal(struct rcu_head *rcu)
+{
+ struct user_key_payload *upayload;
+
+ upayload = container_of(rcu, struct user_key_payload, rcu);
+
+ kfree(upayload);
+
+} /* end user_update_rcu_disposal() */
+
+/*****************************************************************************/
+/*
* update a user defined key
+ * - the key's semaphore is write-locked
*/
static int user_update(struct key *key, const void *data, size_t datalen)
{
- void *new, *zap;
+ struct user_key_payload *upayload, *zap;
int ret;
ret = -EINVAL;
if (datalen <= 0 || datalen > 32767 || !data)
goto error;
- /* copy the data */
+ /* construct a replacement payload */
ret = -ENOMEM;
- new = kmalloc(datalen, GFP_KERNEL);
- if (!new)
+ upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+ if (!upayload)
goto error;
- memcpy(new, data, datalen);
+ upayload->datalen = datalen;
+ memcpy(upayload->data, data, datalen);
/* check the quota and attach the new data */
- zap = new;
- write_lock(&key->lock);
+ zap = upayload;
ret = key_payload_reserve(key, datalen);
if (ret == 0) {
/* attach the new data, displacing the old */
zap = key->payload.data;
- key->payload.data = new;
+ rcu_assign_pointer(key->payload.data, upayload);
key->expiry = 0;
}
- write_unlock(&key->lock);
- kfree(zap);
+ call_rcu(&zap->rcu, user_update_rcu_disposal);
error:
return ret;
@@ -152,13 +182,15 @@ static int user_match(const struct key *key, const void *description)
*/
static void user_destroy(struct key *key)
{
- kfree(key->payload.data);
+ struct user_key_payload *upayload = key->payload.data;
+
+ kfree(upayload);
} /* end user_destroy() */
/*****************************************************************************/
/*
- * describe the user
+ * describe the user key
*/
static void user_describe(const struct key *key, struct seq_file *m)
{
@@ -171,18 +203,23 @@ static void user_describe(const struct key *key, struct seq_file *m)
/*****************************************************************************/
/*
* read the key data
+ * - the key's semaphore is read-locked
*/
static long user_read(const struct key *key,
char __user *buffer, size_t buflen)
{
- long ret = key->datalen;
+ struct user_key_payload *upayload;
+ long ret;
+
+ upayload = rcu_dereference(key->payload.data);
+ ret = upayload->datalen;
/* we can return the data as is */
if (buffer && buflen > 0) {
- if (buflen > key->datalen)
- buflen = key->datalen;
+ if (buflen > upayload->datalen)
+ buflen = upayload->datalen;
- if (copy_to_user(buffer, key->payload.data, buflen) != 0)
+ if (copy_to_user(buffer, upayload->data, buflen) != 0)
ret = -EFAULT;
}