Commit 08397b1a authored by Fabian Frederick's avatar Fabian Frederick Committed by Ben Hutchings

sysv, ipc: fix security-layer leaking

commit 9b24fef9 upstream.

Commit 53dad6d3 ("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: 53dad6d3 ("ipc: fix race with LSMs")
Link: http://lkml.kernel.org/r/1470083552-22966-1-git-send-email-fabf@skynet.beSigned-off-by: default avatarFabian Frederick <fabf@skynet.be>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent c1103c6d
...@@ -678,7 +678,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext, ...@@ -678,7 +678,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
rcu_read_lock(); rcu_read_lock();
ipc_lock_object(&msq->q_perm); ipc_lock_object(&msq->q_perm);
ipc_rcu_putref(msq, ipc_rcu_free); ipc_rcu_putref(msq, msg_rcu_free);
/* raced with RMID? */ /* raced with RMID? */
if (!ipc_valid_object(&msq->q_perm)) { if (!ipc_valid_object(&msq->q_perm)) {
err = -EIDRM; err = -EIDRM;
......
...@@ -442,7 +442,7 @@ static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns ...@@ -442,7 +442,7 @@ static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns
static inline void sem_lock_and_putref(struct sem_array *sma) static inline void sem_lock_and_putref(struct sem_array *sma)
{ {
sem_lock(sma, NULL, -1); 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) static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
...@@ -1385,7 +1385,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, ...@@ -1385,7 +1385,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
rcu_read_unlock(); rcu_read_unlock();
sem_io = ipc_alloc(sizeof(ushort)*nsems); sem_io = ipc_alloc(sizeof(ushort)*nsems);
if (sem_io == NULL) { if (sem_io == NULL) {
ipc_rcu_putref(sma, ipc_rcu_free); ipc_rcu_putref(sma, sem_rcu_free);
return -ENOMEM; return -ENOMEM;
} }
...@@ -1419,20 +1419,20 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum, ...@@ -1419,20 +1419,20 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
if (nsems > SEMMSL_FAST) { if (nsems > SEMMSL_FAST) {
sem_io = ipc_alloc(sizeof(ushort)*nsems); sem_io = ipc_alloc(sizeof(ushort)*nsems);
if (sem_io == NULL) { if (sem_io == NULL) {
ipc_rcu_putref(sma, ipc_rcu_free); ipc_rcu_putref(sma, sem_rcu_free);
return -ENOMEM; return -ENOMEM;
} }
} }
if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) { 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; err = -EFAULT;
goto out_free; goto out_free;
} }
for (i = 0; i < nsems; i++) { for (i = 0; i < nsems; i++) {
if (sem_io[i] > SEMVMX) { if (sem_io[i] > SEMVMX) {
ipc_rcu_putref(sma, ipc_rcu_free); ipc_rcu_putref(sma, sem_rcu_free);
err = -ERANGE; err = -ERANGE;
goto out_free; goto out_free;
} }
...@@ -1722,7 +1722,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid) ...@@ -1722,7 +1722,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
/* step 2: allocate new undo structure */ /* step 2: allocate new undo structure */
new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL); new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
if (!new) { if (!new) {
ipc_rcu_putref(sma, ipc_rcu_free); ipc_rcu_putref(sma, sem_rcu_free);
return ERR_PTR(-ENOMEM); return ERR_PTR(-ENOMEM);
} }
......
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