lkml.org 
[lkml]   [2016]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Date
    Subject[PATCH 3.16 143/346] sysv, ipc: fix security-layer leaking
    3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    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: Ben Hutchings <ben@decadent.org.uk>
    ---
    ipc/msg.c | 2 +-
    ipc/sem.c | 12 ++++++------
    2 files changed, 7 insertions(+), 7 deletions(-)

    --- a/ipc/msg.c
    +++ b/ipc/msg.c
    @@ -678,7 +678,7 @@ 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);
    }

    \
     
     \ /
      Last update: 2016-11-14 03:37    [W:4.096 / U:0.128 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site