|
 |
294b766 |
From b9a532277938798b53178d5a66af6e2915cb27cf Mon Sep 17 00:00:00 2001
|
|
|
294b766 |
From: Linus Torvalds <torvalds@linux-foundation.org>
|
|
|
294b766 |
Date: Wed, 30 Sep 2015 12:48:40 -0400
|
|
|
294b766 |
Subject: [PATCH] Initialize msg/shm IPC objects before doing ipc_addid()
|
|
|
294b766 |
|
|
|
294b766 |
As reported by Dmitry Vyukov, we really shouldn't do ipc_addid() before
|
|
|
294b766 |
having initialized the IPC object state. Yes, we initialize the IPC
|
|
|
294b766 |
object in a locked state, but with all the lockless RCU lookup work,
|
|
|
294b766 |
that IPC object lock no longer means that the state cannot be seen.
|
|
|
294b766 |
|
|
|
294b766 |
We already did this for the IPC semaphore code (see commit e8577d1f0329:
|
|
|
294b766 |
"ipc/sem.c: fully initialize sem_array before making it visible") but we
|
|
|
294b766 |
clearly forgot about msg and shm.
|
|
|
294b766 |
|
|
|
294b766 |
Reported-by: Dmitry Vyukov <dvyukov@google.com>
|
|
|
294b766 |
Cc: Manfred Spraul <manfred@colorfullife.com>
|
|
|
294b766 |
Cc: Davidlohr Bueso <dbueso@suse.de>
|
|
|
294b766 |
Cc: stable@vger.kernel.org
|
|
|
294b766 |
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
|
294b766 |
---
|
|
|
294b766 |
ipc/msg.c | 14 +++++++-------
|
|
|
294b766 |
ipc/shm.c | 13 +++++++------
|
|
|
294b766 |
ipc/util.c | 8 ++++----
|
|
|
294b766 |
3 files changed, 18 insertions(+), 17 deletions(-)
|
|
|
294b766 |
|
|
|
294b766 |
diff --git a/ipc/msg.c b/ipc/msg.c
|
|
|
294b766 |
index 66c4f567eb73..1471db9a7e61 100644
|
|
|
294b766 |
--- a/ipc/msg.c
|
|
|
294b766 |
+++ b/ipc/msg.c
|
|
|
294b766 |
@@ -137,13 +137,6 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
|
|
|
294b766 |
return retval;
|
|
|
294b766 |
}
|
|
|
294b766 |
|
|
|
294b766 |
- /* ipc_addid() locks msq upon success. */
|
|
|
294b766 |
- id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
|
|
|
294b766 |
- if (id < 0) {
|
|
|
294b766 |
- ipc_rcu_putref(msq, msg_rcu_free);
|
|
|
294b766 |
- return id;
|
|
|
294b766 |
- }
|
|
|
294b766 |
-
|
|
|
294b766 |
msq->q_stime = msq->q_rtime = 0;
|
|
|
294b766 |
msq->q_ctime = get_seconds();
|
|
|
294b766 |
msq->q_cbytes = msq->q_qnum = 0;
|
|
|
294b766 |
@@ -153,6 +146,13 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
|
|
|
294b766 |
INIT_LIST_HEAD(&msq->q_receivers);
|
|
|
294b766 |
INIT_LIST_HEAD(&msq->q_senders);
|
|
|
294b766 |
|
|
|
294b766 |
+ /* ipc_addid() locks msq upon success. */
|
|
|
294b766 |
+ id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
|
|
|
294b766 |
+ if (id < 0) {
|
|
|
294b766 |
+ ipc_rcu_putref(msq, msg_rcu_free);
|
|
|
294b766 |
+ return id;
|
|
|
294b766 |
+ }
|
|
|
294b766 |
+
|
|
|
294b766 |
ipc_unlock_object(&msq->q_perm);
|
|
|
294b766 |
rcu_read_unlock();
|
|
|
294b766 |
|
|
|
294b766 |
diff --git a/ipc/shm.c b/ipc/shm.c
|
|
|
294b766 |
index 222131e8e38f..41787276e141 100644
|
|
|
294b766 |
--- a/ipc/shm.c
|
|
|
294b766 |
+++ b/ipc/shm.c
|
|
|
294b766 |
@@ -551,12 +551,6 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
|
|
|
294b766 |
if (IS_ERR(file))
|
|
|
294b766 |
goto no_file;
|
|
|
294b766 |
|
|
|
294b766 |
- id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
|
|
|
294b766 |
- if (id < 0) {
|
|
|
294b766 |
- error = id;
|
|
|
294b766 |
- goto no_id;
|
|
|
294b766 |
- }
|
|
|
294b766 |
-
|
|
|
294b766 |
shp->shm_cprid = task_tgid_vnr(current);
|
|
|
294b766 |
shp->shm_lprid = 0;
|
|
|
294b766 |
shp->shm_atim = shp->shm_dtim = 0;
|
|
|
294b766 |
@@ -565,6 +559,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
|
|
|
294b766 |
shp->shm_nattch = 0;
|
|
|
294b766 |
shp->shm_file = file;
|
|
|
294b766 |
shp->shm_creator = current;
|
|
|
294b766 |
+
|
|
|
294b766 |
+ id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
|
|
|
294b766 |
+ if (id < 0) {
|
|
|
294b766 |
+ error = id;
|
|
|
294b766 |
+ goto no_id;
|
|
|
294b766 |
+ }
|
|
|
294b766 |
+
|
|
|
294b766 |
list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
|
|
|
294b766 |
|
|
|
294b766 |
/*
|
|
|
294b766 |
diff --git a/ipc/util.c b/ipc/util.c
|
|
|
294b766 |
index be4230020a1f..0f401d94b7c6 100644
|
|
|
294b766 |
--- a/ipc/util.c
|
|
|
294b766 |
+++ b/ipc/util.c
|
|
|
294b766 |
@@ -237,6 +237,10 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
|
|
|
294b766 |
rcu_read_lock();
|
|
|
294b766 |
spin_lock(&new->lock);
|
|
|
294b766 |
|
|
|
294b766 |
+ current_euid_egid(&euid, &egid);
|
|
|
294b766 |
+ new->cuid = new->uid = euid;
|
|
|
294b766 |
+ new->gid = new->cgid = egid;
|
|
|
294b766 |
+
|
|
|
294b766 |
id = idr_alloc(&ids->ipcs_idr, new,
|
|
|
294b766 |
(next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
|
|
|
294b766 |
GFP_NOWAIT);
|
|
|
294b766 |
@@ -249,10 +253,6 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
|
|
|
294b766 |
|
|
|
294b766 |
ids->in_use++;
|
|
|
294b766 |
|
|
|
294b766 |
- current_euid_egid(&euid, &egid);
|
|
|
294b766 |
- new->cuid = new->uid = euid;
|
|
|
294b766 |
- new->gid = new->cgid = egid;
|
|
|
294b766 |
-
|
|
|
294b766 |
if (next_id < 0) {
|
|
|
294b766 |
new->seq = ids->seq++;
|
|
|
294b766 |
if (ids->seq > IPCID_SEQ_MAX)
|
|
|
294b766 |
--
|
|
|
294b766 |
2.4.3
|
|
|
294b766 |
|