8 files changed, 327 insertions, 235 deletions

diff --git a/security/keys/compat.c b/security/keys/compat.c
index e8e7ef4a290c..bcdb28533733 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -77,6 +77,9 @@ asmlinkage long compat_sys_keyctl(u32 option,
         case KEYCTL_SET_TIMEOUT:
                 return keyctl_set_timeout(arg2, arg3);
 
+        case KEYCTL_ASSUME_AUTHORITY:
+                return keyctl_assume_authority(arg2);
+
         default:
                 return -EOPNOTSUPP;
         }
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 51f37c0bdb32..e066e6057955 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -107,12 +107,13 @@ extern struct key *request_key_and_link(struct key_type *type,
 struct request_key_auth {
         struct key              *target_key;
         struct task_struct      *context;
+        const char              *callout_info;
         pid_t                   pid;
 };
 
 extern struct key_type key_type_request_key_auth;
 extern struct key *request_key_auth_new(struct key *target,
-                                        struct key **_rkakey);
+                                        const char *callout_info);
 
 extern struct key *key_get_instantiation_authkey(key_serial_t target_id);
 
@@ -137,6 +138,7 @@ extern long keyctl_instantiate_key(key_serial_t, const void __user *,
 extern long keyctl_negate_key(key_serial_t, unsigned, key_serial_t);
 extern long keyctl_set_reqkey_keyring(int);
 extern long keyctl_set_timeout(key_serial_t, unsigned);
+extern long keyctl_assume_authority(key_serial_t);
 
 
 /*
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 299f0ae11cf0..3d2ebae029c1 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -834,6 +834,17 @@ long keyctl_instantiate_key(key_serial_t id,
         if (plen > 32767)
                 goto error;
 
+        /* the appropriate instantiation authorisation key must have been
+         * assumed before calling this */
+        ret = -EPERM;
+        instkey = current->request_key_auth;
+        if (!instkey)
+                goto error;
+
+        rka = instkey->payload.data;
+        if (rka->target_key->serial != id)
+                goto error;
+
         /* pull the payload in if one was supplied */
         payload = NULL;
 
@@ -848,15 +859,6 @@ long keyctl_instantiate_key(key_serial_t id,
                         goto error2;
         }
 
-        /* find the instantiation authorisation key */
-        instkey = key_get_instantiation_authkey(id);
-        if (IS_ERR(instkey)) {
-                ret = PTR_ERR(instkey);
-                goto error2;
-        }
-
-        rka = instkey->payload.data;
-
         /* find the destination keyring amongst those belonging to the
          * requesting task */
         keyring_ref = NULL;
@@ -865,7 +867,7 @@ long keyctl_instantiate_key(key_serial_t id,
                                               KEY_WRITE);
                 if (IS_ERR(keyring_ref)) {
                         ret = PTR_ERR(keyring_ref);
-                        goto error3;
+                        goto error2;
                 }
         }
 
@@ -874,11 +876,17 @@ long keyctl_instantiate_key(key_serial_t id,
                                        key_ref_to_ptr(keyring_ref), instkey);
 
         key_ref_put(keyring_ref);
- error3:
-        key_put(instkey);
- error2:
+
+        /* discard the assumed authority if it's just been disabled by
+         * instantiation of the key */
+        if (ret == 0) {
+                key_put(current->request_key_auth);
+                current->request_key_auth = NULL;
+        }
+
+error2:
         kfree(payload);
- error:
+error:
         return ret;
 
 } /* end keyctl_instantiate_key() */
@@ -895,14 +903,16 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
         key_ref_t keyring_ref;
         long ret;
 
-        /* find the instantiation authorisation key */
-        instkey = key_get_instantiation_authkey(id);
-        if (IS_ERR(instkey)) {
-                ret = PTR_ERR(instkey);
+        /* the appropriate instantiation authorisation key must have been
+         * assumed before calling this */
+        ret = -EPERM;
+        instkey = current->request_key_auth;
+        if (!instkey)
                 goto error;
-        }
 
         rka = instkey->payload.data;
+        if (rka->target_key->serial != id)
+                goto error;
 
         /* find the destination keyring if present (which must also be
          * writable) */
@@ -911,7 +921,7 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
                 keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
                 if (IS_ERR(keyring_ref)) {
                         ret = PTR_ERR(keyring_ref);
-                        goto error2;
+                        goto error;
                 }
         }
 
@@ -920,9 +930,15 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
                                   key_ref_to_ptr(keyring_ref), instkey);
 
         key_ref_put(keyring_ref);
- error2:
-        key_put(instkey);
- error:
+
+        /* discard the assumed authority if it's just been disabled by
+         * instantiation of the key */
+        if (ret == 0) {
+                key_put(current->request_key_auth);
+                current->request_key_auth = NULL;
+        }
+
+error:
         return ret;
 
 } /* end keyctl_negate_key() */
@@ -1007,6 +1023,48 @@ error:
 
 /*****************************************************************************/
 /*
+ * assume the authority to instantiate the specified key
+ */
+long keyctl_assume_authority(key_serial_t id)
+{
+        struct key *authkey;
+        long ret;
+
+        /* special key IDs aren't permitted */
+        ret = -EINVAL;
+        if (id < 0)
+                goto error;
+
+        /* we divest ourselves of authority if given an ID of 0 */
+        if (id == 0) {
+                key_put(current->request_key_auth);
+                current->request_key_auth = NULL;
+                ret = 0;
+                goto error;
+        }
+
+        /* attempt to assume the authority temporarily granted to us whilst we
+         * instantiate the specified key
+         * - the authorisation key must be in the current task's keyrings
+         *   somewhere
+         */
+        authkey = key_get_instantiation_authkey(id);
+        if (IS_ERR(authkey)) {
+                ret = PTR_ERR(authkey);
+                goto error;
+        }
+
+        key_put(current->request_key_auth);
+        current->request_key_auth = authkey;
+        ret = authkey->serial;
+
+error:
+        return ret;
+
+} /* end keyctl_assume_authority() */
+
+/*****************************************************************************/
+/*
  * the key control system call
  */
 asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
@@ -1082,6 +1140,9 @@ asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
                 return keyctl_set_timeout((key_serial_t) arg2,
                                           (unsigned) arg3);
 
+        case KEYCTL_ASSUME_AUTHORITY:
+                return keyctl_assume_authority((key_serial_t) arg2);
+
         default:
                 return -EOPNOTSUPP;
         }
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 09d92d52ef75..d65a180f888d 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -481,51 +481,6 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref,
 
 /*****************************************************************************/
 /*
- * search for an instantiation authorisation key matching a target key
- * - the RCU read lock must be held by the caller
- * - a target_id of zero specifies any valid token
- */
-struct key *keyring_search_instkey(struct key *keyring,
-                                   key_serial_t target_id)
-{
-        struct request_key_auth *rka;
-        struct keyring_list *klist;
-        struct key *instkey;
-        int loop;
-
-        klist = rcu_dereference(keyring->payload.subscriptions);
-        if (klist) {
-                for (loop = 0; loop < klist->nkeys; loop++) {
-                        instkey = klist->keys[loop];
-
-                        if (instkey->type != &key_type_request_key_auth)
-                                continue;
-
-                        rka = instkey->payload.data;
-                        if (target_id && rka->target_key->serial != target_id)
-                                continue;
-
-                        /* the auth key is revoked during instantiation */
-                        if (!test_bit(KEY_FLAG_REVOKED, &instkey->flags))
-                                goto found;
-
-                        instkey = ERR_PTR(-EKEYREVOKED);
-                        goto error;
-                }
-        }
-
-        instkey = ERR_PTR(-EACCES);
-        goto error;
-
-found:
-        atomic_inc(&instkey->usage);
-error:
-        return instkey;
-
-} /* end keyring_search_instkey() */
-
-/*****************************************************************************/
-/*
  * find a keyring with the specified name
  * - all named keyrings are searched
  * - only find keyrings with search permission for the process
diff --git a/security/keys/permission.c b/security/keys/permission.c
index e7f579c0eaf5..3b41f9b52537 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -73,3 +73,35 @@ use_these_perms:
 } /* end key_task_permission() */
 
 EXPORT_SYMBOL(key_task_permission);
+
+/*****************************************************************************/
+/*
+ * validate a key
+ */
+int key_validate(struct key *key)
+{
+        struct timespec now;
+        int ret = 0;
+
+        if (key) {
+                /* check it's still accessible */
+                ret = -EKEYREVOKED;
+                if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
+                    test_bit(KEY_FLAG_DEAD, &key->flags))
+                        goto error;
+
+                /* check it hasn't expired */
+                ret = 0;
+                if (key->expiry) {
+                        now = current_kernel_time();
+                        if (now.tv_sec >= key->expiry)
+                                ret = -EKEYEXPIRED;
+                }
+        }
+
+ error:
+        return ret;
+
+} /* end key_validate() */
+
+EXPORT_SYMBOL(key_validate);
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 566b1cc0118a..74cb79eb917e 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -270,9 +270,14 @@ int copy_thread_group_keys(struct task_struct *tsk)
 int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
 {
         key_check(tsk->thread_keyring);
+        key_check(tsk->request_key_auth);
 
         /* no thread keyring yet */
         tsk->thread_keyring = NULL;
+
+        /* copy the request_key() authorisation for this thread */
+        key_get(tsk->request_key_auth);
+
         return 0;
 
 } /* end copy_keys() */
@@ -290,11 +295,12 @@ void exit_thread_group_keys(struct signal_struct *tg)
 
 /*****************************************************************************/
 /*
- * dispose of keys upon thread exit
+ * dispose of per-thread keys upon thread exit
  */
 void exit_keys(struct task_struct *tsk)
 {
         key_put(tsk->thread_keyring);
+        key_put(tsk->request_key_auth);
 
 } /* end exit_keys() */
 
@@ -382,7 +388,7 @@ key_ref_t search_process_keyrings(struct key_type *type,
                                   struct task_struct *context)
 {
         struct request_key_auth *rka;
-        key_ref_t key_ref, ret, err, instkey_ref;
+        key_ref_t key_ref, ret, err;
 
         /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
          * searchable, but we failed to find a key or we found a negative key;
@@ -461,30 +467,12 @@ key_ref_t search_process_keyrings(struct key_type *type,
                         err = key_ref;
                         break;
                 }
-
-                /* if this process has a session keyring and that has an
-                 * instantiation authorisation key in the bottom level, then we
-                 * also search the keyrings of the process mentioned there */
-                if (context != current)
-                        goto no_key;
-
-                rcu_read_lock();
-                instkey_ref = __keyring_search_one(
-                        make_key_ref(rcu_dereference(
-                                             context->signal->session_keyring),
-                                     1),
-                        &key_type_request_key_auth, NULL, 0);
-                rcu_read_unlock();
-
-                if (IS_ERR(instkey_ref))
-                        goto no_key;
-
-                rka = key_ref_to_ptr(instkey_ref)->payload.data;
-
-                key_ref = search_process_keyrings(type, description, match,
-                                                  rka->context);
-                key_ref_put(instkey_ref);
-
+        }
+        /* or search the user-session keyring */
+        else {
+                key_ref = keyring_search_aux(
+                        make_key_ref(context->user->session_keyring, 1),
+                        context, type, description, match);
                 if (!IS_ERR(key_ref))
                         goto found;
 
@@ -500,11 +488,21 @@ key_ref_t search_process_keyrings(struct key_type *type,
                         break;
                 }
         }
-        /* or search the user-session keyring */
-        else {
-                key_ref = keyring_search_aux(
-                        make_key_ref(context->user->session_keyring, 1),
-                        context, type, description, match);
+
+        /* if this process has an instantiation authorisation key, then we also
+         * search the keyrings of the process mentioned there
+         * - we don't permit access to request_key auth keys via this method
+         */
+        if (context->request_key_auth &&
+            context == current &&
+            type != &key_type_request_key_auth &&
+            key_validate(context->request_key_auth) == 0
+            ) {
+                rka = context->request_key_auth->payload.data;
+
+                key_ref = search_process_keyrings(type, description, match,
+                                                  rka->context);
+
                 if (!IS_ERR(key_ref))
                         goto found;
 
@@ -521,8 +519,6 @@ key_ref_t search_process_keyrings(struct key_type *type,
                 }
         }
 
-
-no_key:
         /* no key - decide on the error we're going to go for */
         key_ref = ret ? ret : err;
 
@@ -628,6 +624,15 @@ key_ref_t lookup_user_key(struct task_struct *context, key_serial_t id,
                 key = ERR_PTR(-EINVAL);
                 goto error;
 
+        case KEY_SPEC_REQKEY_AUTH_KEY:
+                key = context->request_key_auth;
+                if (!key)
+                        goto error;
+
+                atomic_inc(&key->usage);
+                key_ref = make_key_ref(key, 1);
+                break;
+
         default:
                 key_ref = ERR_PTR(-EINVAL);
                 if (id < 1)
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 5cc4bba70db6..f030a0ccbb93 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -29,28 +29,36 @@ DECLARE_WAIT_QUEUE_HEAD(request_key_conswq);
 /*****************************************************************************/
 /*
  * request userspace finish the construction of a key
- * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring> <info>"
+ * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
  */
-static int call_request_key(struct key *key,
-                            const char *op,
-                            const char *callout_info)
+static int call_sbin_request_key(struct key *key,
+                                 struct key *authkey,
+                                 const char *op)
 {
         struct task_struct *tsk = current;
         key_serial_t prkey, sskey;
-        struct key *session_keyring, *rkakey;
-        char *argv[10], *envp[3], uid_str[12], gid_str[12];
+        struct key *keyring;
+        char *argv[9], *envp[3], uid_str[12], gid_str[12];
         char key_str[12], keyring_str[3][12];
+        char desc[20];
         int ret, i;
 
-        kenter("{%d},%s,%s", key->serial, op, callout_info);
+        kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
 
-        /* generate a new session keyring with an auth key in it */
-        session_keyring = request_key_auth_new(key, &rkakey);
-        if (IS_ERR(session_keyring)) {
-                ret = PTR_ERR(session_keyring);
-                goto error;
+        /* allocate a new session keyring */
+        sprintf(desc, "_req.%u", key->serial);
+
+        keyring = keyring_alloc(desc, current->fsuid, current->fsgid, 1, NULL);
+        if (IS_ERR(keyring)) {
+                ret = PTR_ERR(keyring);
+                goto error_alloc;
         }
 
+        /* attach the auth key to the session keyring */
+        ret = __key_link(keyring, authkey);
+        if (ret < 0)
+                goto error_link;
+
         /* record the UID and GID */
         sprintf(uid_str, "%d", current->fsuid);
         sprintf(gid_str, "%d", current->fsgid);
@@ -95,22 +103,19 @@ static int call_request_key(struct key *key,
         argv[i++] = keyring_str[0];
         argv[i++] = keyring_str[1];
         argv[i++] = keyring_str[2];
-        argv[i++] = (char *) callout_info;
         argv[i] = NULL;
 
         /* do it */
-        ret = call_usermodehelper_keys(argv[0], argv, envp, session_keyring, 1);
+        ret = call_usermodehelper_keys(argv[0], argv, envp, keyring, 1);
 
-        /* dispose of the special keys */
-        key_revoke(rkakey);
-        key_put(rkakey);
-        key_put(session_keyring);
+error_link:
+        key_put(keyring);
 
- error:
+error_alloc:
         kleave(" = %d", ret);
         return ret;
 
-} /* end call_request_key() */
+} /* end call_sbin_request_key() */
 
 /*****************************************************************************/
 /*
@@ -122,9 +127,10 @@ static struct key *__request_key_construction(struct key_type *type,
                                               const char *description,
                                               const char *callout_info)
 {
+        request_key_actor_t actor;
         struct key_construction cons;
         struct timespec now;
-        struct key *key;
+        struct key *key, *authkey;
         int ret, negated;
 
         kenter("%s,%s,%s", type->name, description, callout_info);
@@ -143,8 +149,19 @@ static struct key *__request_key_construction(struct key_type *type,
         /* we drop the construction sem here on behalf of the caller */
         up_write(&key_construction_sem);
 
+        /* allocate an authorisation key */
+        authkey = request_key_auth_new(key, callout_info);
+        if (IS_ERR(authkey)) {
+                ret = PTR_ERR(authkey);
+                authkey = NULL;
+                goto alloc_authkey_failed;
+        }
+
         /* make the call */
-        ret = call_request_key(key, "create", callout_info);
+        actor = call_sbin_request_key;
+        if (type->request_key)
+                actor = type->request_key;
+        ret = actor(key, authkey, "create");
         if (ret < 0)
                 goto request_failed;
 
@@ -153,22 +170,29 @@ static struct key *__request_key_construction(struct key_type *type,
         if (!test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
                 goto request_failed;
 
+        key_revoke(authkey);
+        key_put(authkey);
+
         down_write(&key_construction_sem);
         list_del(&cons.link);
         up_write(&key_construction_sem);
 
         /* also give an error if the key was negatively instantiated */
- check_not_negative:
+check_not_negative:
         if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
                 key_put(key);
                 key = ERR_PTR(-ENOKEY);
         }
 
- out:
+out:
         kleave(" = %p", key);
         return key;
 
- request_failed:
+request_failed:
+        key_revoke(authkey);
+        key_put(authkey);
+
+alloc_authkey_failed:
         /* it wasn't instantiated
          * - remove from construction queue
          * - mark the key as dead
@@ -217,7 +241,7 @@ static struct key *__request_key_construction(struct key_type *type,
         key = ERR_PTR(ret);
         goto out;
 
- alloc_failed:
+alloc_failed:
         up_write(&key_construction_sem);
         goto out;
 
@@ -464,35 +488,3 @@ struct key *request_key(struct key_type *type,
 } /* end request_key() */
 
 EXPORT_SYMBOL(request_key);
-
-/*****************************************************************************/
-/*
- * validate a key
- */
-int key_validate(struct key *key)
-{
-        struct timespec now;
-        int ret = 0;
-
-        if (key) {
-                /* check it's still accessible */
-                ret = -EKEYREVOKED;
-                if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
-                    test_bit(KEY_FLAG_DEAD, &key->flags))
-                        goto error;
-
-                /* check it hasn't expired */
-                ret = 0;
-                if (key->expiry) {
-                        now = current_kernel_time();
-                        if (now.tv_sec >= key->expiry)
-                                ret = -EKEYEXPIRED;
-                }
-        }
-
- error:
-        return ret;
-
-} /* end key_validate() */
-
-EXPORT_SYMBOL(key_validate);
diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index a8e4069d48cb..cce6ba6b0323 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -15,11 +15,13 @@
 #include <linux/sched.h>
 #include <linux/err.h>
 #include <linux/seq_file.h>
+#include <asm/uaccess.h>
 #include "internal.h"
 
 static int request_key_auth_instantiate(struct key *, const void *, size_t);
 static void request_key_auth_describe(const struct key *, struct seq_file *);
 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
@@ -30,51 +32,25 @@ struct key_type key_type_request_key_auth = {
         .instantiate    = request_key_auth_instantiate,
         .describe       = request_key_auth_describe,
         .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 request_key_auth *rka, *irka;
-        struct key *instkey;
-        int ret;
-
-        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;
-        }
-
-        return ret;
+        key->payload.data = (struct request_key_auth *) data;
+        return 0;
 
 } /* end request_key_auth_instantiate() */
 
 /*****************************************************************************/
 /*
- *
+ * reading a request-key authorisation key retrieves the callout information
  */
 static void request_key_auth_describe(const struct key *key,
                                       struct seq_file *m)
@@ -83,12 +59,40 @@ static void request_key_auth_describe(const struct key *key,
 
         seq_puts(m, "key:");
         seq_puts(m, key->description);
-        seq_printf(m, " pid:%d", rka->pid);
+        seq_printf(m, " pid:%d ci:%zu", rka->pid, strlen(rka->callout_info));
 
 } /* end request_key_auth_describe() */
 
 /*****************************************************************************/
 /*
+ * read the callout_info data
+ * - 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 = strlen(rka->callout_info);
+        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_read() */
+
+/*****************************************************************************/
+/*
  * destroy an instantiation authorisation token key
  */
 static void request_key_auth_destroy(struct key *key)
@@ -104,56 +108,89 @@ static void request_key_auth_destroy(struct key *key)
 
 /*****************************************************************************/
 /*
- * 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 char *callout_info)
 {
-        struct key *keyring, *rkakey = NULL;
+        struct request_key_auth *rka, *irka;
+        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);
+        }
 
-        keyring = keyring_alloc(desc, current->fsuid, current->fsgid, 1, NULL);
-        if (IS_ERR(keyring)) {
-                kleave("= %ld", PTR_ERR(keyring));
-                return keyring;
+        /* see if the calling process is already servicing the key request of
+         * another process */
+        if (current->request_key_auth) {
+                /* it is - use that instantiation context here too */
+                irka = current->request_key_auth->payload.data;
+                rka->context = irka->context;
+                rka->pid = irka->pid;
         }
+        else {
+                /* it isn't - use this process as the context */
+                rka->context = current;
+                rka->pid = current->pid;
+        }
+
+        rka->target_key = key_get(target);
+        rka->callout_info = callout_info;
 
         /* 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,
+                            current->fsuid, current->fsgid,
+                            KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
+                            KEY_USR_VIEW, 1);
+        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);
-        }
+        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})", authkey->serial);
+        return authkey;
+
+error_inst:
+        key_revoke(authkey);
+        key_put(authkey);
+error_alloc:
+        key_put(rka->target_key);
+        kfree(rka);
+        kleave("= %d", ret);
+        return ERR_PTR(ret);
 
 } /* end request_key_auth_new() */
 
 /*****************************************************************************/
 /*
+ * see if an authorisation key is associated with a particular key
+ */
+static int key_get_instantiation_authkey_match(const struct key *key,
+                                               const void *_id)
+{
+        struct request_key_auth *rka = key->payload.data;
+        key_serial_t id = (key_serial_t)(unsigned long) _id;
+
+        return rka->target_key->serial == id;
+
+} /* end key_get_instantiation_authkey_match() */
+
+/*****************************************************************************/
+/*
  * 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
@@ -162,22 +199,27 @@ struct key *request_key_auth_new(struct key *target, struct key **_rkakey)
  */
 struct key *key_get_instantiation_authkey(key_serial_t target_id)
 {
-        struct task_struct *tsk = current;
-        struct key *instkey;
-
-        /* we must have our own personal session keyring */
-        if (!tsk->signal->session_keyring)
-                return ERR_PTR(-EACCES);
-
-        /* and it must contain a suitable request authorisation key
-         * - lock RCU against session keyring changing
-         */
-        rcu_read_lock();
+        struct key *authkey;
+        key_ref_t authkey_ref;
+
+        authkey_ref = search_process_keyrings(
+                &key_type_request_key_auth,
+                (void *) (unsigned long) target_id,
+                key_get_instantiation_authkey_match,
+                current);
+
+        if (IS_ERR(authkey_ref)) {
+                authkey = ERR_PTR(PTR_ERR(authkey_ref));
+                goto error;
+        }
 
-        instkey = keyring_search_instkey(
-                rcu_dereference(tsk->signal->session_keyring), target_id);
+        authkey = key_ref_to_ptr(authkey_ref);
+        if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
+                key_put(authkey);
+                authkey = ERR_PTR(-EKEYREVOKED);
+        }
 
-        rcu_read_unlock();
-        return instkey;
+error:
+        return authkey;
 
 } /* end key_get_instantiation_authkey() */