The patch titled
Subject: ipc/msg: avoid ipc_rcu_alloc()
has been added to the -mm tree. Its filename is
ipc-msg-avoid-ipc_rcu_alloc.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipc-msg-avoid-ipc_rcu_alloc.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipc-msg-avoid-ipc_rcu_alloc.patch
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: ipc/msg: avoid ipc_rcu_alloc()
Instead of using ipc_rcu_alloc() which only performs the refcount bump,
open code it. This also allows for msg_queue structure layout to be
randomized in the future.
Link: http://lkml.kernel.org/r/20170525185107.12869-12-manfred@xxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/msg.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff -puN ipc/msg.c~ipc-msg-avoid-ipc_rcu_alloc ipc/msg.c
--- a/ipc/msg.c~ipc-msg-avoid-ipc_rcu_alloc
+++ a/ipc/msg.c
@@ -109,6 +109,19 @@ static void msg_rcu_free(struct rcu_head
__msg_free(msq);
}
+static struct msg_queue *msg_alloc(void)
+{
+ struct msg_queue *msq;
+
+ msq = kvmalloc(sizeof(*msq), GFP_KERNEL);
+ if (unlikely(!msq))
+ return NULL;
+
+ atomic_set(&msq->q_perm.refcount, 1);
+
+ return msq;
+}
+
/**
* newque - Create a new msg queue
* @ns: namespace
@@ -123,10 +136,7 @@ static int newque(struct ipc_namespace *
key_t key = params->key;
int msgflg = params->flg;
- BUILD_BUG_ON(offsetof(struct msg_queue, q_perm) != 0);
-
- msq = container_of(ipc_rcu_alloc(sizeof(*msq)), struct msg_queue,
- q_perm);
+ msq = msg_alloc();
if (!msq)
return -ENOMEM;
_
Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are
ipc-drop-non-rcu-allocation.patch
ipc-sem-do-not-use-ipc_rcu_free.patch
ipc-shm-do-not-use-ipc_rcu_free.patch
ipc-msg-do-not-use-ipc_rcu_free.patch
ipc-util-drop-ipc_rcu_free.patch
ipc-sem-avoid-ipc_rcu_alloc.patch
ipc-shm-avoid-ipc_rcu_alloc.patch
ipc-msg-avoid-ipc_rcu_alloc.patch
ipc-util-drop-ipc_rcu_alloc.patch
ipc-move-atomic_set-to-where-it-is-needed.patch
ipc-shm-remove-special-shm_alloc-free.patch
ipc-msg-remove-special-msg_alloc-free.patch
ipc-sem-drop-__sem_free.patch
--
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