ipc/shm.c: use ERR_CAST() for shm_lock() error return

kees · gregkh · commit 59cf0a9339ca · 2018-10-05T16:32:04.000-07:00
This uses ERR_CAST() instead of an open-coded cast, as it is casting across structure pointers, which upsets __randomize_layout: ipc/shm.c: In function `shm_lock': ipc/shm.c:209:9: note: randstruct: casting between randomized structure pointer types (ssa): `struct shmid_kernel' and `struct kern_ipc_perm' return (void *)ipcp; ^~~~~~~~~~~~ Link: http://lkml.kernel.org/r/20180919180722.GA15073@beast Fixes: 82061c5 ("ipc: drop ipc_lock()") Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/ipc/shm.c b/ipc/shm.c
@@ -206,7 +206,7 @@ static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 	 * Callers of shm_lock() must validate the status of the returned ipc
 	 * object pointer and error out as appropriate.
 	 */
-	return (void *)ipcp;
+	return ERR_CAST(ipcp);
 }
 
 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)

Original file line number	Diff line number	Diff line change
`@@ -206,7 +206,7 @@ static inline struct shmid_kernel shm_lock(struct ipc_namespace ns, int id)`
`206`	`206`	`* Callers of shm_lock() must validate the status of the returned ipc`
`207`	`207`	`* object pointer and error out as appropriate.`
`208`	`208`	`*/`
`209`		`- return (void *)ipcp;`
	`209`	`+ return ERR_CAST(ipcp);`
`210`	`210`	`}`
`211`	`211`
`212`	`212`	`static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)`