1 files changed, 176 insertions, 97 deletions

diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index a8e4069d48c..7495a93b4b9 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -1,4 +1,4 @@
-/* request_key_auth.c: request key authorisation controlling key def
+/* Request key authorisation token key definition.
  *
  * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
@@ -8,88 +8,107 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  *
- * See Documentation/keys-request-key.txt
+ * See Documentation/security/keys-request-key.txt
  */
 
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/err.h>
 #include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <asm/uaccess.h>
 #include "internal.h"
+#include <keys/user-type.h>
 
-static int request_key_auth_instantiate(struct key *, const void *, size_t);
+static int request_key_auth_instantiate(struct key *,
+					struct key_preparsed_payload *);
 static void request_key_auth_describe(const struct key *, struct seq_file *);
+static void request_key_auth_revoke(struct key *);
 static void request_key_auth_destroy(struct key *);
+static long request_key_auth_read(const struct key *, char __user *, size_t);
 
 /*
- * the request-key authorisation key type definition
+ * The request-key authorisation key type definition.
  */
 struct key_type key_type_request_key_auth = {
 	.name		= ".request_key_auth",
 	.def_datalen	= sizeof(struct request_key_auth),
 	.instantiate	= request_key_auth_instantiate,
 	.describe	= request_key_auth_describe,
+	.revoke		= request_key_auth_revoke,
 	.destroy	= request_key_auth_destroy,
+	.read		= request_key_auth_read,
 };
 
-/*****************************************************************************/
 /*
- * instantiate a request-key authorisation record
+ * Instantiate a request-key authorisation key.
  */
 static int request_key_auth_instantiate(struct key *key,
-					const void *data,
-					size_t datalen)
+					struct key_preparsed_payload *prep)
 {
-	struct request_key_auth *rka, *irka;
-	struct key *instkey;
-	int ret;
+	key->payload.data = (struct request_key_auth *)prep->data;
+	return 0;
+}
 
-	ret = -ENOMEM;
-	rka = kmalloc(sizeof(*rka), GFP_KERNEL);
-	if (rka) {
-		/* see if the calling process is already servicing the key
-		 * request of another process */
-		instkey = key_get_instantiation_authkey(0);
-		if (!IS_ERR(instkey)) {
-			/* it is - use that instantiation context here too */
-			irka = instkey->payload.data;
-			rka->context = irka->context;
-			rka->pid = irka->pid;
-			key_put(instkey);
-		}
-		else {
-			/* it isn't - use this process as the context */
-			rka->context = current;
-			rka->pid = current->pid;
-		}
-
-		rka->target_key = key_get((struct key *) data);
-		key->payload.data = rka;
-		ret = 0;
+/*
+ * Describe an authorisation token.
+ */
+static void request_key_auth_describe(const struct key *key,
+				      struct seq_file *m)
+{
+	struct request_key_auth *rka = key->payload.data;
+
+	seq_puts(m, "key:");
+	seq_puts(m, key->description);
+	if (key_is_instantiated(key))
+		seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
+}
+
+/*
+ * Read the callout_info data (retrieves the callout information).
+ * - the key's semaphore is read-locked
+ */
+static long request_key_auth_read(const struct key *key,
+				  char __user *buffer, size_t buflen)
+{
+	struct request_key_auth *rka = key->payload.data;
+	size_t datalen;
+	long ret;
+
+	datalen = rka->callout_len;
+	ret = datalen;
+
+	/* we can return the data as is */
+	if (buffer && buflen > 0) {
+		if (buflen > datalen)
+			buflen = datalen;
+
+		if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
+			ret = -EFAULT;
 	}
 
 	return ret;
+}
 
-} /* end request_key_auth_instantiate() */
-
-/*****************************************************************************/
 /*
+ * Handle revocation of an authorisation token key.
  *
+ * Called with the key sem write-locked.
  */
-static void request_key_auth_describe(const struct key *key,
-				      struct seq_file *m)
+static void request_key_auth_revoke(struct key *key)
 {
 	struct request_key_auth *rka = key->payload.data;
 
-	seq_puts(m, "key:");
-	seq_puts(m, key->description);
-	seq_printf(m, " pid:%d", rka->pid);
+	kenter("{%d}", key->serial);
 
-} /* end request_key_auth_describe() */
+	if (rka->cred) {
+		put_cred(rka->cred);
+		rka->cred = NULL;
+	}
+}
 
-/*****************************************************************************/
 /*
- * destroy an instantiation authorisation token key
+ * Destroy an instantiation authorisation token key.
  */
 static void request_key_auth_destroy(struct key *key)
 {
@@ -97,87 +116,147 @@ static void request_key_auth_destroy(struct key *key)
 
 	kenter("{%d}", key->serial);
 
+	if (rka->cred) {
+		put_cred(rka->cred);
+		rka->cred = NULL;
+	}
+
 	key_put(rka->target_key);
+	key_put(rka->dest_keyring);
+	kfree(rka->callout_info);
 	kfree(rka);
+}
 
-} /* end request_key_auth_destroy() */
-
-/*****************************************************************************/
 /*
- * create a session keyring to be for the invokation of /sbin/request-key and
- * stick an authorisation token in it
+ * Create an authorisation token for /sbin/request-key or whoever to gain
+ * access to the caller's security data.
  */
-struct key *request_key_auth_new(struct key *target, struct key **_rkakey)
+struct key *request_key_auth_new(struct key *target, const void *callout_info,
+				 size_t callout_len, struct key *dest_keyring)
 {
-	struct key *keyring, *rkakey = NULL;
+	struct request_key_auth *rka, *irka;
+	const struct cred *cred = current->cred;
+	struct key *authkey = NULL;
 	char desc[20];
 	int ret;
 
 	kenter("%d,", target->serial);
 
-	/* allocate a new session keyring */
-	sprintf(desc, "_req.%u", target->serial);
+	/* allocate a auth record */
+	rka = kmalloc(sizeof(*rka), GFP_KERNEL);
+	if (!rka) {
+		kleave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
+	}
+	rka->callout_info = kmalloc(callout_len, GFP_KERNEL);
+	if (!rka->callout_info) {
+		kleave(" = -ENOMEM");
+		kfree(rka);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* see if the calling process is already servicing the key request of
+	 * another process */
+	if (cred->request_key_auth) {
+		/* it is - use that instantiation context here too */
+		down_read(&cred->request_key_auth->sem);
 
-	keyring = keyring_alloc(desc, current->fsuid, current->fsgid, 1, NULL);
-	if (IS_ERR(keyring)) {
-		kleave("= %ld", PTR_ERR(keyring));
-		return keyring;
+		/* if the auth key has been revoked, then the key we're
+		 * servicing is already instantiated */
+		if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags))
+			goto auth_key_revoked;
+
+		irka = cred->request_key_auth->payload.data;
+		rka->cred = get_cred(irka->cred);
+		rka->pid = irka->pid;
+
+		up_read(&cred->request_key_auth->sem);
+	}
+	else {
+		/* it isn't - use this process as the context */
+		rka->cred = get_cred(cred);
+		rka->pid = current->pid;
 	}
 
+	rka->target_key = key_get(target);
+	rka->dest_keyring = key_get(dest_keyring);
+	memcpy(rka->callout_info, callout_info, callout_len);
+	rka->callout_len = callout_len;
+
 	/* allocate the auth key */
 	sprintf(desc, "%x", target->serial);
 
-	rkakey = key_alloc(&key_type_request_key_auth, desc,
-			   current->fsuid, current->fsgid,
-			   KEY_POS_VIEW | KEY_USR_VIEW, 1);
-	if (IS_ERR(rkakey)) {
-		key_put(keyring);
-		kleave("= %ld", PTR_ERR(rkakey));
-		return rkakey;
+	authkey = key_alloc(&key_type_request_key_auth, desc,
+			    cred->fsuid, cred->fsgid, cred,
+			    KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
+			    KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA);
+	if (IS_ERR(authkey)) {
+		ret = PTR_ERR(authkey);
+		goto error_alloc;
 	}
 
-	/* construct and attach to the keyring */
-	ret = key_instantiate_and_link(rkakey, target, 0, keyring, NULL);
-	if (ret < 0) {
-		key_revoke(rkakey);
-		key_put(rkakey);
-		key_put(keyring);
-		kleave("= %d", ret);
-		return ERR_PTR(ret);
-	}
+	/* construct the auth key */
+	ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
+	if (ret < 0)
+		goto error_inst;
 
-	*_rkakey = rkakey;
-	kleave(" = {%d} ({%d})", keyring->serial, rkakey->serial);
-	return keyring;
+	kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
+	return authkey;
 
-} /* end request_key_auth_new() */
+auth_key_revoked:
+	up_read(&cred->request_key_auth->sem);
+	kfree(rka->callout_info);
+	kfree(rka);
+	kleave("= -EKEYREVOKED");
+	return ERR_PTR(-EKEYREVOKED);
+
+error_inst:
+	key_revoke(authkey);
+	key_put(authkey);
+error_alloc:
+	key_put(rka->target_key);
+	key_put(rka->dest_keyring);
+	kfree(rka->callout_info);
+	kfree(rka);
+	kleave("= %d", ret);
+	return ERR_PTR(ret);
+}
 
-/*****************************************************************************/
 /*
- * get the authorisation key for instantiation of a specific key if attached to
- * the current process's keyrings
- * - this key is inserted into a keyring and that is set as /sbin/request-key's
- *   session keyring
- * - a target_id of zero specifies any valid token
+ * Search the current process's keyrings for the authorisation key for
+ * instantiation of a key.
  */
 struct key *key_get_instantiation_authkey(key_serial_t target_id)
 {
-	struct task_struct *tsk = current;
-	struct key *instkey;
+	char description[16];
+	struct keyring_search_context ctx = {
+		.index_key.type		= &key_type_request_key_auth,
+		.index_key.description	= description,
+		.cred			= current_cred(),
+		.match			= user_match,
+		.match_data		= description,
+		.flags			= KEYRING_SEARCH_LOOKUP_DIRECT,
+	};
+	struct key *authkey;
+	key_ref_t authkey_ref;
 
-	/* we must have our own personal session keyring */
-	if (!tsk->signal->session_keyring)
-		return ERR_PTR(-EACCES);
+	sprintf(description, "%x", target_id);
 
-	/* and it must contain a suitable request authorisation key
-	 * - lock RCU against session keyring changing
-	 */
-	rcu_read_lock();
+	authkey_ref = search_process_keyrings(&ctx);
 
-	instkey = keyring_search_instkey(
-		rcu_dereference(tsk->signal->session_keyring), target_id);
+	if (IS_ERR(authkey_ref)) {
+		authkey = ERR_CAST(authkey_ref);
+		if (authkey == ERR_PTR(-EAGAIN))
+			authkey = ERR_PTR(-ENOKEY);
+		goto error;
+	}
 
-	rcu_read_unlock();
-	return instkey;
+	authkey = key_ref_to_ptr(authkey_ref);
+	if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
+		key_put(authkey);
+		authkey = ERR_PTR(-EKEYREVOKED);
+	}
 
-} /* end key_get_instantiation_authkey() */
+error:
+	return authkey;
+}