5 files changed, 38 insertions, 6 deletions

diff --git a/security/keys/internal.h b/security/keys/internal.h
index 5d4402a..38783dc 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -124,6 +124,7 @@ extern struct key *find_keyring_by_name(const char *name, bool skip_perm_check);
 extern int install_user_keyrings(void);
 extern int install_thread_keyring_to_cred(struct cred *);
 extern int install_process_keyring_to_cred(struct cred *);
+extern int install_session_keyring_to_cred(struct cred *, struct key *);
 
 extern struct key *request_key_and_link(struct key_type *type,
 					const char *description,
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 8f4dce1..13074b4 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1269,7 +1269,7 @@ long keyctl_session_to_parent(void)
 		goto not_permitted;
 
 	/* the parent must be single threaded */
-	if (atomic_read(&parent->signal->count) != 1)
+	if (!thread_group_empty(parent))
 		goto not_permitted;
 
 	/* the parent and the child must have different session keyrings or
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index ef03a82..d37f713 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -669,7 +669,7 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
 	struct keyring_list *klist =
 		container_of(rcu, struct keyring_list, rcu);
 
-	if (klist->delkey != USHORT_MAX)
+	if (klist->delkey != USHRT_MAX)
 		key_put(klist->keys[klist->delkey]);
 	kfree(klist);
 }
@@ -746,7 +746,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type,
 			max += klist->maxkeys;
 
 		ret = -ENFILE;
-		if (max > USHORT_MAX - 1)
+		if (max > USHRT_MAX - 1)
 			goto error_quota;
 		size = sizeof(*klist) + sizeof(struct key *) * max;
 		if (size > PAGE_SIZE)
@@ -763,7 +763,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type,
 			       sizeof(struct key *) * klist->nkeys);
 			nklist->delkey = klist->nkeys;
 			nklist->nkeys = klist->nkeys + 1;
-			klist->delkey = USHORT_MAX;
+			klist->delkey = USHRT_MAX;
 		} else {
 			nklist->nkeys = 1;
 			nklist->delkey = 0;
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 20a38fe..6b8e4ff 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -216,8 +216,7 @@ static int install_process_keyring(void)
 /*
  * install a session keyring directly to a credentials struct
  */
-static int install_session_keyring_to_cred(struct cred *cred,
-					   struct key *keyring)
+int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
 {
 	unsigned long flags;
 	struct key *old;
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index f656e9c..f5ec9ac 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -58,6 +58,38 @@ void complete_request_key(struct key_construction *cons, int error)
 }
 EXPORT_SYMBOL(complete_request_key);
 
+static int umh_keys_init(struct subprocess_info *info)
+{
+	struct cred *cred = (struct cred*)current_cred();
+	struct key *keyring = info->data;
+	/*
+	 * This is called in context of freshly forked kthread before
+	 * kernel_execve(), we can just change our ->session_keyring.
+	 */
+	return install_session_keyring_to_cred(cred, keyring);
+}
+
+static void umh_keys_cleanup(struct subprocess_info *info)
+{
+	struct key *keyring = info->data;
+	key_put(keyring);
+}
+
+static int call_usermodehelper_keys(char *path, char **argv, char **envp,
+			 struct key *session_keyring, enum umh_wait wait)
+{
+	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
+	struct subprocess_info *info =
+		call_usermodehelper_setup(path, argv, envp, gfp_mask);
+
+	if (!info)
+		return -ENOMEM;
+
+	call_usermodehelper_setfns(info, umh_keys_init, umh_keys_cleanup,
+					key_get(session_keyring));
+	return call_usermodehelper_exec(info, wait);
+}
+
 /*
  * request userspace finish the construction of a key
  * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"