1. 18 Apr, 2016 38 commits
  2. 13 Apr, 2016 2 commits
    • Vasily Kulikov's avatar
      include/linux/poison.h: fix LIST_POISON{1,2} offset · 46460a03
      Vasily Kulikov authored
      [ Upstream commit 8a5e5e02 ]
      
      Poison pointer values should be small enough to find a room in
      non-mmap'able/hardly-mmap'able space.  E.g.  on x86 "poison pointer space"
      is located starting from 0x0.  Given unprivileged users cannot mmap
      anything below mmap_min_addr, it should be safe to use poison pointers
      lower than mmap_min_addr.
      
      The current poison pointer values of LIST_POISON{1,2} might be too big for
      mmap_min_addr values equal or less than 1 MB (common case, e.g.  Ubuntu
      uses only 0x10000).  There is little point to use such a big value given
      the "poison pointer space" below 1 MB is not yet exhausted.  Changing it
      to a smaller value solves the problem for small mmap_min_addr setups.
      
      The values are suggested by Solar Designer:
      http://www.openwall.com/lists/oss-security/2015/05/02/6Signed-off-by: default avatarVasily Kulikov <segoon@openwall.com>
      Cc: Solar Designer <solar@openwall.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.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 avatarSasha Levin <sasha.levin@oracle.com>
      46460a03
    • David Howells's avatar
      KEYS: Fix handling of stored error in a negatively instantiated user key · d979e967
      David Howells authored
      [ Upstream commit 096fe9ea ]
      
      If a user key gets negatively instantiated, an error code is cached in the
      payload area.  A negatively instantiated key may be then be positively
      instantiated by updating it with valid data.  However, the ->update key
      type method must be aware that the error code may be there.
      
      The following may be used to trigger the bug in the user key type:
      
          keyctl request2 user user "" @u
          keyctl add user user "a" @u
      
      which manifests itself as:
      
      	BUG: unable to handle kernel paging request at 00000000ffffff8a
      	IP: [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046
      	PGD 7cc30067 PUD 0
      	Oops: 0002 [#1] SMP
      	Modules linked in:
      	CPU: 3 PID: 2644 Comm: a.out Not tainted 4.3.0+ #49
      	Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
      	task: ffff88003ddea700 ti: ffff88003dd88000 task.ti: ffff88003dd88000
      	RIP: 0010:[<ffffffff810a376f>]  [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280
      	 [<ffffffff810a376f>] __call_rcu.constprop.76+0x1f/0x280 kernel/rcu/tree.c:3046
      	RSP: 0018:ffff88003dd8bdb0  EFLAGS: 00010246
      	RAX: 00000000ffffff82 RBX: 0000000000000000 RCX: 0000000000000001
      	RDX: ffffffff81e3fe40 RSI: 0000000000000000 RDI: 00000000ffffff82
      	RBP: ffff88003dd8bde0 R08: ffff88007d2d2da0 R09: 0000000000000000
      	R10: 0000000000000000 R11: ffff88003e8073c0 R12: 00000000ffffff82
      	R13: ffff88003dd8be68 R14: ffff88007d027600 R15: ffff88003ddea700
      	FS:  0000000000b92880(0063) GS:ffff88007fd00000(0000) knlGS:0000000000000000
      	CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
      	CR2: 00000000ffffff8a CR3: 000000007cc5f000 CR4: 00000000000006e0
      	Stack:
      	 ffff88003dd8bdf0 ffffffff81160a8a 0000000000000000 00000000ffffff82
      	 ffff88003dd8be68 ffff88007d027600 ffff88003dd8bdf0 ffffffff810a39e5
      	 ffff88003dd8be20 ffffffff812a31ab ffff88007d027600 ffff88007d027620
      	Call Trace:
      	 [<ffffffff810a39e5>] kfree_call_rcu+0x15/0x20 kernel/rcu/tree.c:3136
      	 [<ffffffff812a31ab>] user_update+0x8b/0xb0 security/keys/user_defined.c:129
      	 [<     inline     >] __key_update security/keys/key.c:730
      	 [<ffffffff8129e5c1>] key_create_or_update+0x291/0x440 security/keys/key.c:908
      	 [<     inline     >] SYSC_add_key security/keys/keyctl.c:125
      	 [<ffffffff8129fc21>] SyS_add_key+0x101/0x1e0 security/keys/keyctl.c:60
      	 [<ffffffff8185f617>] entry_SYSCALL_64_fastpath+0x12/0x6a arch/x86/entry/entry_64.S:185
      
      Note the error code (-ENOKEY) in EDX.
      
      A similar bug can be tripped by:
      
          keyctl request2 trusted user "" @u
          keyctl add trusted user "a" @u
      
      This should also affect encrypted keys - but that has to be correctly
      parameterised or it will fail with EINVAL before getting to the bit that
      will crashes.
      Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Acked-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
      Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
      Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      d979e967