Commit Graph

3 Commits

Author SHA1 Message Date
Kees Cook
7dea04e088 ipc/mqueue.c: only perform resource calculation if user valid
[ Upstream commit a318f12ed8843cfac53198390c74a565c632f417 ]

Andreas Christoforou reported:

  UBSAN: Undefined behaviour in ipc/mqueue.c:414:49 signed integer overflow:
  9 * 2305843009213693951 cannot be represented in type 'long int'
  ...
  Call Trace:
    mqueue_evict_inode+0x8e7/0xa10 ipc/mqueue.c:414
    evict+0x472/0x8c0 fs/inode.c:558
    iput_final fs/inode.c:1547 [inline]
    iput+0x51d/0x8c0 fs/inode.c:1573
    mqueue_get_inode+0x8eb/0x1070 ipc/mqueue.c:320
    mqueue_create_attr+0x198/0x440 ipc/mqueue.c:459
    vfs_mkobj+0x39e/0x580 fs/namei.c:2892
    prepare_open ipc/mqueue.c:731 [inline]
    do_mq_open+0x6da/0x8e0 ipc/mqueue.c:771

Which could be triggered by:

        struct mq_attr attr = {
                .mq_flags = 0,
                .mq_maxmsg = 9,
                .mq_msgsize = 0x1fffffffffffffff,
                .mq_curmsgs = 0,
        };

        if (mq_open("/testing", 0x40, 3, &attr) == (mqd_t) -1)
                perror("mq_open");

mqueue_get_inode() was correctly rejecting the giant mq_msgsize, and
preparing to return -EINVAL.  During the cleanup, it calls
mqueue_evict_inode() which performed resource usage tracking math for
updating "user", before checking if there was a valid "user" at all
(which would indicate that the calculations would be sane).  Instead,
delay this check to after seeing a valid "user".

The overflow was real, but the results went unused, so while the flaw is
harmless, it's noisy for kernel fuzzers, so just fix it by moving the
calculation under the non-NULL "user" where it actually gets used.

Link: http://lkml.kernel.org/r/201906072207.ECB65450@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Andreas Christoforou <andreaschristofo@gmail.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
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: Sasha Levin <sashal@kernel.org>
2020-04-06 20:27:32 +02:00
Li Rongqing
bed04fc10a ipc: prevent lockup on alloc_msg and free_msg
[ Upstream commit d6a2946a88f524a47cc9b79279667137899db807 ]

msgctl10 of ltp triggers the following lockup When CONFIG_KASAN is
enabled on large memory SMP systems, the pages initialization can take a
long time, if msgctl10 requests a huge block memory, and it will block
rcu scheduler, so release cpu actively.

After adding schedule() in free_msg, free_msg can not be called when
holding spinlock, so adding msg to a tmp list, and free it out of
spinlock

  rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
  rcu:     Tasks blocked on level-1 rcu_node (CPUs 16-31): P32505
  rcu:     Tasks blocked on level-1 rcu_node (CPUs 48-63): P34978
  rcu:     (detected by 11, t=35024 jiffies, g=44237529, q=16542267)
  msgctl10        R  running task    21608 32505   2794 0x00000082
  Call Trace:
   preempt_schedule_irq+0x4c/0xb0
   retint_kernel+0x1b/0x2d
  RIP: 0010:__is_insn_slot_addr+0xfb/0x250
  Code: 82 1d 00 48 8b 9b 90 00 00 00 4c 89 f7 49 c1 ee 03 e8 59 83 1d 00 48 b8 00 00 00 00 00 fc ff df 4c 39 eb 48 89 9d 58 ff ff ff <41> c6 04 06 f8 74 66 4c 8d 75 98 4c 89 f1 48 c1 e9 03 48 01 c8 48
  RSP: 0018:ffff88bce041f758 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
  RAX: dffffc0000000000 RBX: ffffffff8471bc50 RCX: ffffffff828a2a57
  RDX: dffffc0000000000 RSI: dffffc0000000000 RDI: ffff88bce041f780
  RBP: ffff88bce041f828 R08: ffffed15f3f4c5b3 R09: ffffed15f3f4c5b3
  R10: 0000000000000001 R11: ffffed15f3f4c5b2 R12: 000000318aee9b73
  R13: ffffffff8471bc50 R14: 1ffff1179c083ef0 R15: 1ffff1179c083eec
   kernel_text_address+0xc1/0x100
   __kernel_text_address+0xe/0x30
   unwind_get_return_address+0x2f/0x50
   __save_stack_trace+0x92/0x100
   create_object+0x380/0x650
   __kmalloc+0x14c/0x2b0
   load_msg+0x38/0x1a0
   do_msgsnd+0x19e/0xcf0
   do_syscall_64+0x117/0x400
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

  rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
  rcu:     Tasks blocked on level-1 rcu_node (CPUs 0-15): P32170
  rcu:     (detected by 14, t=35016 jiffies, g=44237525, q=12423063)
  msgctl10        R  running task    21608 32170  32155 0x00000082
  Call Trace:
   preempt_schedule_irq+0x4c/0xb0
   retint_kernel+0x1b/0x2d
  RIP: 0010:lock_acquire+0x4d/0x340
  Code: 48 81 ec c0 00 00 00 45 89 c6 4d 89 cf 48 8d 6c 24 20 48 89 3c 24 48 8d bb e4 0c 00 00 89 74 24 0c 48 c7 44 24 20 b3 8a b5 41 <48> c1 ed 03 48 c7 44 24 28 b4 25 18 84 48 c7 44 24 30 d0 54 7a 82
  RSP: 0018:ffff88af83417738 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
  RAX: dffffc0000000000 RBX: ffff88bd335f3080 RCX: 0000000000000002
  RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88bd335f3d64
  RBP: ffff88af83417758 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000001 R11: ffffed13f3f745b2 R12: 0000000000000000
  R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
   is_bpf_text_address+0x32/0xe0
   kernel_text_address+0xec/0x100
   __kernel_text_address+0xe/0x30
   unwind_get_return_address+0x2f/0x50
   __save_stack_trace+0x92/0x100
   save_stack+0x32/0xb0
   __kasan_slab_free+0x130/0x180
   kfree+0xfa/0x2d0
   free_msg+0x24/0x50
   do_msgrcv+0x508/0xe60
   do_syscall_64+0x117/0x400
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Davidlohr said:
 "So after releasing the lock, the msg rbtree/list is empty and new
  calls will not see those in the newly populated tmp_msg list, and
  therefore they cannot access the delayed msg freeing pointers, which
  is good. Also the fact that the node_cache is now freed before the
  actual messages seems to be harmless as this is wanted for
  msg_insert() avoiding GFP_ATOMIC allocations, and after releasing the
  info->lock the thing is freed anyway so it should not change things"

Link: http://lkml.kernel.org/r/1552029161-4957-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-06 19:01:36 +02:00
prashantpaddune
3bca37f224 A750FXXU4CTBC 2020-03-27 21:51:54 +05:30