Merge commit 'tags/keys-fixes-20171018' into fixes-v4.14-rc5

14 files changed, 88 insertions, 53 deletions

diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index 91eafad..6462e66 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -45,6 +45,7 @@ config BIG_KEYS
 	bool "Large payload keys"
 	depends on KEYS
 	depends on TMPFS
+	select CRYPTO
 	select CRYPTO_AES
 	select CRYPTO_GCM
 	help
diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index e607830..929e149 100644
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -247,7 +247,7 @@ void big_key_revoke(struct key *key)
 
 	/* clear the quota */
 	key_payload_reserve(key, 0);
-	if (key_is_instantiated(key) &&
+	if (key_is_positive(key) &&
 	    (size_t)key->payload.data[big_key_len] > BIG_KEY_FILE_THRESHOLD)
 		vfs_truncate(path, 0);
 }
@@ -279,7 +279,7 @@ void big_key_describe(const struct key *key, struct seq_file *m)
 
 	seq_puts(m, key->description);
 
-	if (key_is_instantiated(key))
+	if (key_is_positive(key))
 		seq_printf(m, ": %zu [%s]",
 			   datalen,
 			   datalen > BIG_KEY_FILE_THRESHOLD ? "file" : "buff");
diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index 69855ba..d92cbf9 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -309,6 +309,13 @@ static struct key *request_user_key(const char *master_desc, const u8 **master_k
 
 	down_read(&ukey->sem);
 	upayload = user_key_payload_locked(ukey);
+	if (!upayload) {
+		/* key was revoked before we acquired its semaphore */
+		up_read(&ukey->sem);
+		key_put(ukey);
+		ukey = ERR_PTR(-EKEYREVOKED);
+		goto error;
+	}
 	*master_key = upayload->data;
 	*master_keylen = upayload->datalen;
 error:
@@ -847,7 +854,7 @@ static int encrypted_update(struct key *key, struct key_preparsed_payload *prep)
 	size_t datalen = prep->datalen;
 	int ret = 0;
 
-	if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
+	if (key_is_negative(key))
 		return -ENOKEY;
 	if (datalen <= 0 || datalen > 32767 || !prep->data)
 		return -EINVAL;
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 87cb260..f01d48c 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -129,15 +129,15 @@ static noinline void key_gc_unused_keys(struct list_head *keys)
 	while (!list_empty(keys)) {
 		struct key *key =
 			list_entry(keys->next, struct key, graveyard_link);
+		short state = key->state;
+
 		list_del(&key->graveyard_link);
 
 		kdebug("- %u", key->serial);
 		key_check(key);
 
 		/* Throw away the key data if the key is instantiated */
-		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
-		    !test_bit(KEY_FLAG_NEGATIVE, &key->flags) &&
-		    key->type->destroy)
+		if (state == KEY_IS_POSITIVE && key->type->destroy)
 			key->type->destroy(key);
 
 		security_key_free(key);
@@ -151,7 +151,7 @@ static noinline void key_gc_unused_keys(struct list_head *keys)
 		}
 
 		atomic_dec(&key->user->nkeys);
-		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
+		if (state != KEY_IS_UNINSTANTIATED)
 			atomic_dec(&key->user->nikeys);
 
 		key_user_put(key->user);
diff --git a/security/keys/key.c b/security/keys/key.c
index eb914a8..83bf4b4 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -402,6 +402,18 @@ int key_payload_reserve(struct key *key, size_t datalen)
 EXPORT_SYMBOL(key_payload_reserve);
 
 /*
+ * Change the key state to being instantiated.
+ */
+static void mark_key_instantiated(struct key *key, int reject_error)
+{
+	/* Commit the payload before setting the state; barrier versus
+	 * key_read_state().
+	 */
+	smp_store_release(&key->state,
+			  (reject_error < 0) ? reject_error : KEY_IS_POSITIVE);
+}
+
+/*
  * Instantiate a key and link it into the target keyring atomically.  Must be
  * called with the target keyring's semaphore writelocked.  The target key's
  * semaphore need not be locked as instantiation is serialised by
@@ -424,14 +436,14 @@ static int __key_instantiate_and_link(struct key *key,
 	mutex_lock(&key_construction_mutex);
 
 	/* can't instantiate twice */
-	if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
+	if (key->state == KEY_IS_UNINSTANTIATED) {
 		/* instantiate the key */
 		ret = key->type->instantiate(key, prep);
 
 		if (ret == 0) {
 			/* mark the key as being instantiated */
 			atomic_inc(&key->user->nikeys);
-			set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
+			mark_key_instantiated(key, 0);
 
 			if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags))
 				awaken = 1;
@@ -577,13 +589,10 @@ int key_reject_and_link(struct key *key,
 	mutex_lock(&key_construction_mutex);
 
 	/* can't instantiate twice */
-	if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
+	if (key->state == KEY_IS_UNINSTANTIATED) {
 		/* mark the key as being negatively instantiated */
 		atomic_inc(&key->user->nikeys);
-		key->reject_error = -error;
-		smp_wmb();
-		set_bit(KEY_FLAG_NEGATIVE, &key->flags);
-		set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
+		mark_key_instantiated(key, -error);
 		now = current_kernel_time();
 		key->expiry = now.tv_sec + timeout;
 		key_schedule_gc(key->expiry + key_gc_delay);
@@ -752,8 +761,8 @@ static inline key_ref_t __key_update(key_ref_t key_ref,
 
 	ret = key->type->update(key, prep);
 	if (ret == 0)
-		/* updating a negative key instantiates it */
-		clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
+		/* Updating a negative key positively instantiates it */
+		mark_key_instantiated(key, 0);
 
 	up_write(&key->sem);
 
@@ -936,6 +945,16 @@ error:
 	 */
 	__key_link_end(keyring, &index_key, edit);
 
+	key = key_ref_to_ptr(key_ref);
+	if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) {
+		ret = wait_for_key_construction(key, true);
+		if (ret < 0) {
+			key_ref_put(key_ref);
+			key_ref = ERR_PTR(ret);
+			goto error_free_prep;
+		}
+	}
+
 	key_ref = __key_update(key_ref, &prep);
 	goto error_free_prep;
 }
@@ -986,8 +1005,8 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen)
 
 	ret = key->type->update(key, &prep);
 	if (ret == 0)
-		/* updating a negative key instantiates it */
-		clear_bit(KEY_FLAG_NEGATIVE, &key->flags);
+		/* Updating a negative key positively instantiates it */
+		mark_key_instantiated(key, 0);
 
 	up_write(&key->sem);
 
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 365ff85..76d22f72 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -766,10 +766,9 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
 
 	key = key_ref_to_ptr(key_ref);
 
-	if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
-		ret = -ENOKEY;
-		goto error2;
-	}
+	ret = key_read_state(key);
+	if (ret < 0)
+		goto error2; /* Negatively instantiated */
 
 	/* see if we can read it directly */
 	ret = key_permission(key_ref, KEY_NEED_READ);
@@ -901,7 +900,7 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
 		atomic_dec(&key->user->nkeys);
 		atomic_inc(&newowner->nkeys);
 
-		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
+		if (key->state != KEY_IS_UNINSTANTIATED) {
 			atomic_dec(&key->user->nikeys);
 			atomic_inc(&newowner->nikeys);
 		}
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 4fa82a8..a7e51f7 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -414,7 +414,7 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m)
 	else
 		seq_puts(m, "[anon]");
 
-	if (key_is_instantiated(keyring)) {
+	if (key_is_positive(keyring)) {
 		if (keyring->keys.nr_leaves_on_tree != 0)
 			seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree);
 		else
@@ -553,7 +553,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 {
 	struct keyring_search_context *ctx = iterator_data;
 	const struct key *key = keyring_ptr_to_key(object);
-	unsigned long kflags = key->flags;
+	unsigned long kflags = READ_ONCE(key->flags);
+	short state = READ_ONCE(key->state);
 
 	kenter("{%d}", key->serial);
 
@@ -565,6 +566,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 
 	/* skip invalidated, revoked and expired keys */
 	if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
+		time_t expiry = READ_ONCE(key->expiry);
+
 		if (kflags & ((1 << KEY_FLAG_INVALIDATED) |
 			      (1 << KEY_FLAG_REVOKED))) {
 			ctx->result = ERR_PTR(-EKEYREVOKED);
@@ -572,7 +575,7 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 			goto skipped;
 		}
 
-		if (key->expiry && ctx->now.tv_sec >= key->expiry) {
+		if (expiry && ctx->now.tv_sec >= expiry) {
 			if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED))
 				ctx->result = ERR_PTR(-EKEYEXPIRED);
 			kleave(" = %d [expire]", ctx->skipped_ret);
@@ -597,9 +600,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 
 	if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
 		/* we set a different error code if we pass a negative key */
-		if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
-			smp_rmb();
-			ctx->result = ERR_PTR(key->reject_error);
+		if (state < 0) {
+			ctx->result = ERR_PTR(state);
 			kleave(" = %d [neg]", ctx->skipped_ret);
 			goto skipped;
 		}
diff --git a/security/keys/permission.c b/security/keys/permission.c
index 732cc0b..a72b4dd 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -88,7 +88,8 @@ EXPORT_SYMBOL(key_task_permission);
  */
 int key_validate(const struct key *key)
 {
-	unsigned long flags = key->flags;
+	unsigned long flags = READ_ONCE(key->flags);
+	time_t expiry = READ_ONCE(key->expiry);
 
 	if (flags & (1 << KEY_FLAG_INVALIDATED))
 		return -ENOKEY;
@@ -99,9 +100,9 @@ int key_validate(const struct key *key)
 		return -EKEYREVOKED;
 
 	/* check it hasn't expired */
-	if (key->expiry) {
+	if (expiry) {
 		struct timespec now = current_kernel_time();
-		if (now.tv_sec >= key->expiry)
+		if (now.tv_sec >= expiry)
 			return -EKEYEXPIRED;
 	}
 
diff --git a/security/keys/proc.c b/security/keys/proc.c
index de83430..6d1fcbb 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -179,9 +179,12 @@ static int proc_keys_show(struct seq_file *m, void *v)
 	struct rb_node *_p = v;
 	struct key *key = rb_entry(_p, struct key, serial_node);
 	struct timespec now;
+	time_t expiry;
 	unsigned long timo;
+	unsigned long flags;
 	key_ref_t key_ref, skey_ref;
 	char xbuf[16];
+	short state;
 	int rc;
 
 	struct keyring_search_context ctx = {
@@ -217,12 +220,13 @@ static int proc_keys_show(struct seq_file *m, void *v)
 	rcu_read_lock();
 
 	/* come up with a suitable timeout value */
-	if (key->expiry == 0) {
+	expiry = READ_ONCE(key->expiry);
+	if (expiry == 0) {
 		memcpy(xbuf, "perm", 5);
-	} else if (now.tv_sec >= key->expiry) {
+	} else if (now.tv_sec >= expiry) {
 		memcpy(xbuf, "expd", 5);
 	} else {
-		timo = key->expiry - now.tv_sec;
+		timo = expiry - now.tv_sec;
 
 		if (timo < 60)
 			sprintf(xbuf, "%lus", timo);
@@ -236,18 +240,21 @@ 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 : '-')
+	state = key_read_state(key);
 
+#define showflag(FLAGS, LETTER, FLAG) \
+	((FLAGS & (1 << FLAG)) ? LETTER : '-')
+
+	flags = READ_ONCE(key->flags);
 	seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
 		   key->serial,
-		   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),
-		   showflag(key, 'i', KEY_FLAG_INVALIDATED),
+		   state != KEY_IS_UNINSTANTIATED ? 'I' : '-',
+		   showflag(flags, 'R', KEY_FLAG_REVOKED),
+		   showflag(flags, 'D', KEY_FLAG_DEAD),
+		   showflag(flags, 'Q', KEY_FLAG_IN_QUOTA),
+		   showflag(flags, 'U', KEY_FLAG_USER_CONSTRUCT),
+		   state < 0 ? 'N' : '-',
+		   showflag(flags, 'i', KEY_FLAG_INVALIDATED),
 		   refcount_read(&key->usage),
 		   xbuf,
 		   key->perm,
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 293d359..740affd 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -730,7 +730,7 @@ try_again:
 
 	ret = -EIO;
 	if (!(lflags & KEY_LOOKUP_PARTIAL) &&
-	    !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
+	    key_read_state(key) == KEY_IS_UNINSTANTIATED)
 		goto invalid_key;
 
 	/* check the permissions */
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 63e63a4..e8036cd 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -595,10 +595,9 @@ int wait_for_key_construction(struct key *key, bool intr)
 			  intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
 	if (ret)
 		return -ERESTARTSYS;
-	if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
-		smp_rmb();
-		return key->reject_error;
-	}
+	ret = key_read_state(key);
+	if (ret < 0)
+		return ret;
 	return key_validate(key);
 }
 EXPORT_SYMBOL(wait_for_key_construction);
diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index 6ebf1af..424e1d9 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -73,7 +73,7 @@ static void request_key_auth_describe(const struct key *key,
 
 	seq_puts(m, "key:");
 	seq_puts(m, key->description);
-	if (key_is_instantiated(key))
+	if (key_is_positive(key))
 		seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
 }
 
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ddfaebf..bd85315 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -1066,7 +1066,7 @@ static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
 	char *datablob;
 	int ret = 0;
 
-	if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
+	if (key_is_negative(key))
 		return -ENOKEY;
 	p = key->payload.data[0];
 	if (!p->migratable)
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 3d8c68e..9f558be 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -114,7 +114,7 @@ int user_update(struct key *key, struct key_preparsed_payload *prep)
 
 	/* attach the new data, displacing the old */
 	key->expiry = prep->expiry;
-	if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags))
+	if (key_is_positive(key))
 		zap = dereference_key_locked(key);
 	rcu_assign_keypointer(key, prep->payload.data[0]);
 	prep->payload.data[0] = NULL;
@@ -162,7 +162,7 @@ EXPORT_SYMBOL_GPL(user_destroy);
 void user_describe(const struct key *key, struct seq_file *m)
 {
 	seq_puts(m, key->description);
-	if (key_is_instantiated(key))
+	if (key_is_positive(key))
 		seq_printf(m, ": %u", key->datalen);
 }