1 files changed, 44 insertions, 1 deletions

diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index 0ecc2e8d2bd0..cb9817ced3fd 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -20,6 +20,7 @@
 
 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_revoke(struct key *);
 static void request_key_auth_destroy(struct key *);
 static long request_key_auth_read(const struct key *, char __user *, size_t);
 
@@ -31,6 +32,7 @@ struct key_type key_type_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,
 };
@@ -93,6 +95,24 @@ static long request_key_auth_read(const struct key *key,
 
 /*****************************************************************************/
 /*
+ * handle revocation of an authorisation token key
+ * - called with the key sem write-locked
+ */
+static void request_key_auth_revoke(struct key *key)
+{
+        struct request_key_auth *rka = key->payload.data;
+
+        kenter("{%d}", key->serial);
+
+        if (rka->context) {
+                put_task_struct(rka->context);
+                rka->context = NULL;
+        }
+
+} /* end request_key_auth_revoke() */
+
+/*****************************************************************************/
+/*
  * destroy an instantiation authorisation token key
  */
 static void request_key_auth_destroy(struct key *key)
@@ -101,6 +121,11 @@ static void request_key_auth_destroy(struct key *key)
 
         kenter("{%d}", key->serial);
 
+        if (rka->context) {
+                put_task_struct(rka->context);
+                rka->context = NULL;
+        }
+
         key_put(rka->target_key);
         kfree(rka);
 
@@ -131,14 +156,26 @@ struct key *request_key_auth_new(struct key *target, const char *callout_info)
          * another process */
         if (current->request_key_auth) {
                 /* it is - use that instantiation context here too */
+                down_read(&current->request_key_auth->sem);
+
+                /* if the auth key has been revoked, then the key we're
+                 * servicing is already instantiated */
+                if (test_bit(KEY_FLAG_REVOKED,
+                             &current->request_key_auth->flags))
+                        goto auth_key_revoked;
+
                 irka = current->request_key_auth->payload.data;
                 rka->context = irka->context;
                 rka->pid = irka->pid;
+                get_task_struct(rka->context);
+
+                up_read(&current->request_key_auth->sem);
         }
         else {
                 /* it isn't - use this process as the context */
                 rka->context = current;
                 rka->pid = current->pid;
+                get_task_struct(rka->context);
         }
 
         rka->target_key = key_get(target);
@@ -161,9 +198,15 @@ struct key *request_key_auth_new(struct key *target, const char *callout_info)
         if (ret < 0)
                 goto error_inst;
 
-        kleave(" = {%d})", authkey->serial);
+        kleave(" = {%d}", authkey->serial);
         return authkey;
 
+auth_key_revoked:
+        up_read(&current->request_key_auth->sem);
+        kfree(rka);
+        kleave("= -EKEYREVOKED");
+        return ERR_PTR(-EKEYREVOKED);
+
 error_inst:
         key_revoke(authkey);
         key_put(authkey);