Commit 53dad6d3a8e5
("ipc: fix race with LSMs") updated ipc_rcu_putref() to receive
rcu freeing function but used generic ipc_rcu_free() instead
of msg_rcu_free() which does security cleaning.
Running LTP msgsnd06 with kmemleak gives the following:
cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88003c0a11f8 (size 8):
comm "msgsnd06", pid 1645, jiffies 4294672526 (age 6.549s)
hex dump (first 8 bytes):
1b 00 00 00 01 00 00 00 ........
backtrace:
[<ffffffff818e2c43>] kmemleak_alloc+0x23/0x40
[<ffffffff81177f31>] kmem_cache_alloc_trace+0xe1/0x180
[<ffffffff812d42af>] selinux_msg_queue_alloc_security+0x3f/0xd0
[<ffffffff812cc6be>] security_msg_queue_alloc+0x2e/0x40
[<ffffffff812b94ee>] newque+0x4e/0x150
[<ffffffff812b8cb9>] ipcget+0x159/0x1b0
[<ffffffff812b98d9>] SyS_msgget+0x39/0x40
[<ffffffff818e7bdb>] entry_SYSCALL_64_fastpath+0x13/0x8f
[<ffffffffffffffff>] 0xffffffffffffffff
Manfred Spraul suggested to fix sem.c as well and
Davidlohr Bueso to only use ipc_rcu_free in case of security
allocation failure in newary()
Signed-off-by: Fabian Frederick <f...@skynet.be>
---
This patch replaces "ipc/msg.c: fix memory leak in do_msgsnd()"
Semaphore update is untested.
ipc/msg.c | 2 +-
ipc/sem.c | 12 ++++++------
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/ipc/msg.c b/ipc/msg.c
index 59559a2..43e9631 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -681,7 +681,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
rcu_read_lock();
ipc_lock_object(&msq->q_perm);
- ipc_rcu_putref(msq, ipc_rcu_free);
+ ipc_rcu_putref(msq, msg_rcu_free);
/* raced with RMID? */
if (!ipc_valid_object(&msq->q_perm)) {
err = -EIDRM;
diff --git a/ipc/sem.c b/ipc/sem.c
index 3987a97..5e318c5 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -463,7 +463,7 @@ static inline struct sem_array
*sem_obtain_object_check(struct ipc_namespace *ns
static inline void sem_lock_and_putref(struct sem_array *sma)
{
sem_lock(sma, NULL, -1);
- ipc_rcu_putref(sma, ipc_rcu_free);
+ ipc_rcu_putref(sma, sem_rcu_free);
}
static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
@@ -1407,7 +1407,7 @@ static int semctl_main(struct ipc_namespace *ns, int
semid, int semnum,
rcu_read_unlock();
sem_io = ipc_alloc(sizeof(ushort)*nsems);
if (sem_io == NULL) {
- ipc_rcu_putref(sma, ipc_rcu_free);
+ ipc_rcu_putref(sma, sem_rcu_free);
return -ENOMEM;
}
@@ -1441,20 +1441,20 @@ static int semctl_main(struct ipc_namespace *ns, int
semid, int semnum,
if (nsems > SEMMSL_FAST) {
sem_io = ipc_alloc(sizeof(ushort)*nsems);
if (sem_io == NULL) {
- ipc_rcu_putref(sma, ipc_rcu_free);
+ ipc_rcu_putref(sma, sem_rcu_free);
return -ENOMEM;
}
}
if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) {
- ipc_rcu_putref(sma, ipc_rcu_free);
+ ipc_rcu_putref(sma, sem_rcu_free);
err = -EFAULT;
goto out_free;
}
for (i = 0; i < nsems; i++) {
if (sem_io[i] > SEMVMX) {
- ipc_rcu_putref(sma, ipc_rcu_free);
+ ipc_rcu_putref(sma, sem_rcu_free);
err = -ERANGE;
goto out_free;
}
@@ -1746,7 +1746,7 @@ static struct sem_undo *find_alloc_undo(struct
ipc_namespace *ns, int semid)
/* step 2: allocate new undo structure */
new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems,
GFP_KERNEL);
if (!new) {
- ipc_rcu_putref(sma, ipc_rcu_free);
+ ipc_rcu_putref(sma, sem_rcu_free);
return ERR_PTR(-ENOMEM);
}
--
2.8.1
