From: Manfred Spraul <manfred@colorfullife.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Dmitry Vyukov <dvyukov@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
1vier1@web.de, Kees Cook <keescook@chromium.org>,
Manfred Spraul <manfred@colorfullife.com>
Subject: [PATCH 01/12] ipc: reorganize initialization of kern_ipc_perm.id
Date: Mon, 9 Jul 2018 17:10:08 +0200 [thread overview]
Message-ID: <20180709151019.1336-2-manfred@colorfullife.com> (raw)
In-Reply-To: <20180709151019.1336-1-manfred@colorfullife.com>
ipc_addid() initializes kern_ipc_perm.id after having called
ipc_idr_alloc().
Thus a parallel semop() or msgrcv() that uses ipc_obtain_object_idr()
may see an uninitialized value.
The patch moves all accesses to kern_ipc_perm.id under the spin_lock().
The issues is related to the finding of
syzbot+2827ef6b3385deb07eaf@syzkaller.appspotmail.com:
syzbot found an issue with kern_ipc_perm.seq
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
---
ipc/msg.c | 19 ++++++++++++++-----
ipc/sem.c | 18 +++++++++++++-----
ipc/shm.c | 19 ++++++++++++++-----
3 files changed, 41 insertions(+), 15 deletions(-)
diff --git a/ipc/msg.c b/ipc/msg.c
index 3b6545302598..829c2062ded4 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -491,7 +491,6 @@ static int msgctl_stat(struct ipc_namespace *ns, int msqid,
int cmd, struct msqid64_ds *p)
{
struct msg_queue *msq;
- int id = 0;
int err;
memset(p, 0, sizeof(*p));
@@ -503,7 +502,6 @@ static int msgctl_stat(struct ipc_namespace *ns, int msqid,
err = PTR_ERR(msq);
goto out_unlock;
}
- id = msq->q_perm.id;
} else { /* IPC_STAT */
msq = msq_obtain_object_check(ns, msqid);
if (IS_ERR(msq)) {
@@ -548,10 +546,21 @@ static int msgctl_stat(struct ipc_namespace *ns, int msqid,
p->msg_lspid = pid_vnr(msq->q_lspid);
p->msg_lrpid = pid_vnr(msq->q_lrpid);
- ipc_unlock_object(&msq->q_perm);
- rcu_read_unlock();
- return id;
+ if (cmd == IPC_STAT) {
+ /*
+ * As defined in SUS:
+ * Return 0 on success
+ */
+ err = 0;
+ } else {
+ /*
+ * MSG_STAT and MSG_STAT_ANY (both Linux specific)
+ * Return the full id, including the sequence counter
+ */
+ err = msq->q_perm.id;
+ }
+ ipc_unlock_object(&msq->q_perm);
out_unlock:
rcu_read_unlock();
return err;
diff --git a/ipc/sem.c b/ipc/sem.c
index 5af1943ad782..e8971fa1d847 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1222,7 +1222,6 @@ static int semctl_stat(struct ipc_namespace *ns, int semid,
{
struct sem_array *sma;
time64_t semotime;
- int id = 0;
int err;
memset(semid64, 0, sizeof(*semid64));
@@ -1234,7 +1233,6 @@ static int semctl_stat(struct ipc_namespace *ns, int semid,
err = PTR_ERR(sma);
goto out_unlock;
}
- id = sma->sem_perm.id;
} else { /* IPC_STAT */
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
@@ -1274,10 +1272,20 @@ static int semctl_stat(struct ipc_namespace *ns, int semid,
#endif
semid64->sem_nsems = sma->sem_nsems;
+ if (cmd == IPC_STAT) {
+ /*
+ * As defined in SUS:
+ * Return 0 on success
+ */
+ err = 0;
+ } else {
+ /*
+ * SEM_STAT and SEM_STAT_ANY (both Linux specific)
+ * Return the full id, including the sequence counter
+ */
+ err = sma->sem_perm.id;
+ }
ipc_unlock_object(&sma->sem_perm);
- rcu_read_unlock();
- return id;
-
out_unlock:
rcu_read_unlock();
return err;
diff --git a/ipc/shm.c b/ipc/shm.c
index 051a3e1fb8df..59fe8b3b3794 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -949,7 +949,6 @@ static int shmctl_stat(struct ipc_namespace *ns, int shmid,
int cmd, struct shmid64_ds *tbuf)
{
struct shmid_kernel *shp;
- int id = 0;
int err;
memset(tbuf, 0, sizeof(*tbuf));
@@ -961,7 +960,6 @@ static int shmctl_stat(struct ipc_namespace *ns, int shmid,
err = PTR_ERR(shp);
goto out_unlock;
}
- id = shp->shm_perm.id;
} else { /* IPC_STAT */
shp = shm_obtain_object_check(ns, shmid);
if (IS_ERR(shp)) {
@@ -1011,10 +1009,21 @@ static int shmctl_stat(struct ipc_namespace *ns, int shmid,
tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
tbuf->shm_nattch = shp->shm_nattch;
- ipc_unlock_object(&shp->shm_perm);
- rcu_read_unlock();
- return id;
+ if (cmd == IPC_STAT) {
+ /*
+ * As defined in SUS:
+ * Return 0 on success
+ */
+ err = 0;
+ } else {
+ /*
+ * SHM_STAT and SHM_STAT_ANY (both Linux specific)
+ * Return the full id, including the sequence counter
+ */
+ err = shp->shm_perm.id;
+ }
+ ipc_unlock_object(&shp->shm_perm);
out_unlock:
rcu_read_unlock();
return err;
--
2.17.1
next prev parent reply other threads:[~2018-07-09 15:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 15:10 [PATCH 0/12 V2] ipc: cleanups & bugfixes, rhashtable update Manfred Spraul
2018-07-09 15:10 ` Manfred Spraul [this message]
2018-07-10 22:08 ` [PATCH 01/12] ipc: reorganize initialization of kern_ipc_perm.id Davidlohr Bueso
2018-07-09 15:10 ` [PATCH 02/12] ipc: reorganize initialization of kern_ipc_perm.seq Manfred Spraul
2018-07-09 15:10 ` [PATCH 03/12] ipc/util.c: Use ipc_rcu_putref() for failues in ipc_addid() Manfred Spraul
2018-07-09 15:10 ` [PATCH 04/12] ipc: Rename ipcctl_pre_down_nolock() Manfred Spraul
2018-07-09 19:49 ` Davidlohr Bueso
2018-07-09 15:10 ` [PATCH 05/12] ipc/util.c: correct comment in ipc_obtain_object_check Manfred Spraul
2018-07-09 18:46 ` Davidlohr Bueso
2018-07-09 15:10 ` [PATCH 06/12] ipc: rename ipc_lock() to ipc_lock_idr() Manfred Spraul
2018-07-11 19:38 ` Davidlohr Bueso
2018-07-09 15:10 ` [PATCH 07/12] ipc_idr_alloc refactoring Manfred Spraul
2018-07-11 19:52 ` Davidlohr Bueso
2018-07-11 20:00 ` Dmitry Vyukov
2018-07-09 15:10 ` [PATCH 08/12] lib/rhashtable: simplify bucket_table_alloc() Manfred Spraul
2018-07-09 15:10 ` [PATCH 09/12] lib/rhashtable: guarantee initial hashtable allocation Manfred Spraul
2018-07-09 15:10 ` [PATCH 10/12] ipc: get rid of ids->tables_initialized hack Manfred Spraul
2018-07-09 15:10 ` [PATCH 11/12] ipc: simplify ipc initialization Manfred Spraul
2018-07-09 21:42 ` Andrew Morton
2018-07-09 23:55 ` Davidlohr Bueso
2018-07-09 15:10 ` [PATCH 12/12] ipc/util.c: Further ipc_idr_alloc cleanups Manfred Spraul
2018-07-09 17:05 ` Dmitry Vyukov
2018-07-09 18:22 ` Manfred Spraul
2018-07-09 18:31 ` Dmitry Vyukov
2018-07-09 20:09 ` [PATCH 0/12 V2] ipc: cleanups & bugfixes, rhashtable update Davidlohr Bueso
2018-07-10 4:44 ` Manfred Spraul
2018-07-10 22:10 ` Davidlohr Bueso
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