ipc: rename ipcctl_pre_down_nolock()

manfred-colorfu · torvalds · commit 4241c1a30407 · 2018-08-22T10:52:51.000-07:00
Both the comment and the name of ipcctl_pre_down_nolock() are misleading: The function must be called while holdling the rw semaphore. Therefore the patch renames the function to ipcctl_obtain_check(): This name matches the other names used in util.c: - "obtain" function look up a pointer in the idr, without acquiring the object lock. - The caller is responsible for locking. - _check means that the sequence number is checked. Link: http://lkml.kernel.org/r/20180712185241.4017-5-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Kees Cook <keescook@chromium.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/msg.c b/ipc/msg.c
@@ -386,7 +386,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
 	down_write(&msg_ids(ns).rwsem);
 	rcu_read_lock();
 
-	ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
+	ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
 				      &msqid64->msg_perm, msqid64->msg_qbytes);
 	if (IS_ERR(ipcp)) {
 		err = PTR_ERR(ipcp);
diff --git a/ipc/sem.c b/ipc/sem.c
@@ -1596,7 +1596,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
 	down_write(&sem_ids(ns).rwsem);
 	rcu_read_lock();
 
-	ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
+	ipcp = ipcctl_obtain_check(ns, &sem_ids(ns), semid, cmd,
 				      &semid64->sem_perm, 0);
 	if (IS_ERR(ipcp)) {
 		err = PTR_ERR(ipcp);
diff --git a/ipc/shm.c b/ipc/shm.c
@@ -881,7 +881,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 	down_write(&shm_ids(ns).rwsem);
 	rcu_read_lock();
 
-	ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
+	ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
 				      &shmid64->shm_perm, 0);
 	if (IS_ERR(ipcp)) {
 		err = PTR_ERR(ipcp);
diff --git a/ipc/util.c b/ipc/util.c
@@ -688,7 +688,7 @@ int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
 }
 
 /**
- * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd
+ * ipcctl_obtain_check - retrieve an ipc object and check permissions
  * @ns:  ipc namespace
  * @ids:  the table of ids where to look for the ipc
  * @id:   the id of the ipc to retrieve
@@ -698,16 +698,16 @@ int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
  *
  * This function does some common audit and permissions check for some IPC_XXX
  * cmd and is called from semctl_down, shmctl_down and msgctl_down.
- * It must be called without any lock held and:
  *
- *   - retrieves the ipc with the given id in the given table.
+ * It:
+ *   - retrieves the ipc object with the given id in the given table.
  *   - performs some audit and permission check, depending on the given cmd
  *   - returns a pointer to the ipc object or otherwise, the corresponding
  *     error.
  *
  * Call holding the both the rwsem and the rcu read lock.
  */
-struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
+struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
 					struct ipc_ids *ids, int id, int cmd,
 					struct ipc64_perm *perm, int extra_perm)
 {
diff --git a/ipc/util.h b/ipc/util.h
@@ -148,7 +148,7 @@ struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
-struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
+struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
 					     struct ipc_ids *ids, int id, int cmd,
 					     struct ipc64_perm *perm, int extra_perm);
 

Original file line number	Diff line number	Diff line change
`@@ -688,7 +688,7 @@ int ipc_update_perm(struct ipc64_perm in, struct kern_ipc_perm out)`
`688`	`688`	`}`
`689`	`689`
`690`	`690`	`/**`
`691`		`- * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd`
	`691`	`+ * ipcctl_obtain_check - retrieve an ipc object and check permissions`
`692`	`692`	`* @ns: ipc namespace`
`693`	`693`	`* @ids: the table of ids where to look for the ipc`
`694`	`694`	`* @id: the id of the ipc to retrieve`
`@@ -698,16 +698,16 @@ int ipc_update_perm(struct ipc64_perm in, struct kern_ipc_perm out)`
`698`	`698`	`*`
`699`	`699`	`* This function does some common audit and permissions check for some IPC_XXX`
`700`	`700`	`* cmd and is called from semctl_down, shmctl_down and msgctl_down.`
`701`		`- * It must be called without any lock held and:`
`702`	`701`	`*`
`703`		`- * - retrieves the ipc with the given id in the given table.`
	`702`	`+ * It:`
	`703`	`+ * - retrieves the ipc object with the given id in the given table.`
`704`	`704`	`* - performs some audit and permission check, depending on the given cmd`
`705`	`705`	`* - returns a pointer to the ipc object or otherwise, the corresponding`
`706`	`706`	`* error.`
`707`	`707`	`*`
`708`	`708`	`* Call holding the both the rwsem and the rcu read lock.`
`709`	`709`	`*/`
`710`		`-struct kern_ipc_perm ipcctl_pre_down_nolock(struct ipc_namespace ns,`
	`710`	`+struct kern_ipc_perm ipcctl_obtain_check(struct ipc_namespace ns,`
`711`	`711`	`struct ipc_ids *ids, int id, int cmd,`
`712`	`712`	`struct ipc64_perm *perm, int extra_perm)`
`713`	`713`	`{`