| From 9b24fef9f0410fb5364245d6cc2bd044cc064007 Mon Sep 17 00:00:00 2001 |
| From: Fabian Frederick <fabf@skynet.be> |
| Date: Tue, 2 Aug 2016 14:03:07 -0700 |
| Subject: sysv, ipc: fix security-layer leaking |
| |
| From: Fabian Frederick <fabf@skynet.be> |
| |
| commit 9b24fef9f0410fb5364245d6cc2bd044cc064007 upstream. |
| |
| 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: |
| kmemleak_alloc+0x23/0x40 |
| kmem_cache_alloc_trace+0xe1/0x180 |
| selinux_msg_queue_alloc_security+0x3f/0xd0 |
| security_msg_queue_alloc+0x2e/0x40 |
| newque+0x4e/0x150 |
| ipcget+0x159/0x1b0 |
| SyS_msgget+0x39/0x40 |
| entry_SYSCALL_64_fastpath+0x13/0x8f |
| |
| 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() |
| |
| Fixes: 53dad6d3a8e ("ipc: fix race with LSMs") |
| Link: http://lkml.kernel.org/r/1470083552-22966-1-git-send-email-fabf@skynet.be |
| Signed-off-by: Fabian Frederick <fabf@skynet.be> |
| Cc: Davidlohr Bueso <dbueso@suse.de> |
| Cc: Manfred Spraul <manfred@colorfullife.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| ipc/msg.c | 2 +- |
| ipc/sem.c | 12 ++++++------ |
| 2 files changed, 7 insertions(+), 7 deletions(-) |
| |
| --- a/ipc/msg.c |
| +++ b/ipc/msg.c |
| @@ -680,7 +680,7 @@ long do_msgsnd(int msqid, long mtype, vo |
| 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; |
| --- a/ipc/sem.c |
| +++ b/ipc/sem.c |
| @@ -442,7 +442,7 @@ static inline struct sem_array *sem_obta |
| 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) |
| @@ -1385,7 +1385,7 @@ static int semctl_main(struct ipc_namesp |
| 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; |
| } |
| |
| @@ -1419,20 +1419,20 @@ static int semctl_main(struct ipc_namesp |
| 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; |
| } |
| @@ -1722,7 +1722,7 @@ static struct sem_undo *find_alloc_undo( |
| /* 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); |
| } |
| |