1. 24 7月, 2014 3 次提交
    • E
      CAPABILITIES: remove undefined caps from all processes · 7d8b6c63
      Eric Paris 提交于
      This is effectively a revert of 7b9a7ec5
      plus fixing it a different way...
      
      We found, when trying to run an application from an application which
      had dropped privs that the kernel does security checks on undefined
      capability bits.  This was ESPECIALLY difficult to debug as those
      undefined bits are hidden from /proc/$PID/status.
      
      Consider a root application which drops all capabilities from ALL 4
      capability sets.  We assume, since the application is going to set
      eff/perm/inh from an array that it will clear not only the defined caps
      less than CAP_LAST_CAP, but also the higher 28ish bits which are
      undefined future capabilities.
      
      The BSET gets cleared differently.  Instead it is cleared one bit at a
      time.  The problem here is that in security/commoncap.c::cap_task_prctl()
      we actually check the validity of a capability being read.  So any task
      which attempts to 'read all things set in bset' followed by 'unset all
      things set in bset' will not even attempt to unset the undefined bits
      higher than CAP_LAST_CAP.
      
      So the 'parent' will look something like:
      CapInh:	0000000000000000
      CapPrm:	0000000000000000
      CapEff:	0000000000000000
      CapBnd:	ffffffc000000000
      
      All of this 'should' be fine.  Given that these are undefined bits that
      aren't supposed to have anything to do with permissions.  But they do...
      
      So lets now consider a task which cleared the eff/perm/inh completely
      and cleared all of the valid caps in the bset (but not the invalid caps
      it couldn't read out of the kernel).  We know that this is exactly what
      the libcap-ng library does and what the go capabilities library does.
      They both leave you in that above situation if you try to clear all of
      you capapabilities from all 4 sets.  If that root task calls execve()
      the child task will pick up all caps not blocked by the bset.  The bset
      however does not block bits higher than CAP_LAST_CAP.  So now the child
      task has bits in eff which are not in the parent.  These are
      'meaningless' undefined bits, but still bits which the parent doesn't
      have.
      
      The problem is now in cred_cap_issubset() (or any operation which does a
      subset test) as the child, while a subset for valid cap bits, is not a
      subset for invalid cap bits!  So now we set durring commit creds that
      the child is not dumpable.  Given it is 'more priv' than its parent.  It
      also means the parent cannot ptrace the child and other stupidity.
      
      The solution here:
      1) stop hiding capability bits in status
      	This makes debugging easier!
      
      2) stop giving any task undefined capability bits.  it's simple, it you
      don't put those invalid bits in CAP_FULL_SET you won't get them in init
      and you won't get them in any other task either.
      	This fixes the cap_issubset() tests and resulting fallout (which
      	made the init task in a docker container untraceable among other
      	things)
      
      3) mask out undefined bits when sys_capset() is called as it might use
      ~0, ~0 to denote 'all capabilities' for backward/forward compatibility.
      	This lets 'capsh --caps="all=eip" -- -c /bin/bash' run.
      
      4) mask out undefined bit when we read a file capability off of disk as
      again likely all bits are set in the xattr for forward/backward
      compatibility.
      	This lets 'setcap all+pe /bin/bash; /bin/bash' run
      Signed-off-by: NEric Paris <eparis@redhat.com>
      Reviewed-by: NKees Cook <keescook@chromium.org>
      Cc: Andrew Vagin <avagin@openvz.org>
      Cc: Andrew G. Morgan <morgan@kernel.org>
      Cc: Serge E. Hallyn <serge.hallyn@canonical.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Steve Grubb <sgrubb@redhat.com>
      Cc: Dan Walsh <dwalsh@redhat.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: NJames Morris <james.l.morris@oracle.com>
      7d8b6c63
    • J
      Merge tag 'keys-next-20140722' of... · 4ca332e1
      James Morris 提交于
      Merge tag 'keys-next-20140722' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs into next
      4ca332e1
    • T
      commoncap: don't alloc the credential unless needed in cap_task_prctl · 6d6f3328
      Tetsuo Handa 提交于
      In function cap_task_prctl(), we would allocate a credential
      unconditionally and then check if we support the requested function.
      If not we would release this credential with abort_creds() by using
      RCU method. But on some archs such as powerpc, the sys_prctl is heavily
      used to get/set the floating point exception mode. So the unnecessary
      allocating/releasing of credential not only introduce runtime overhead
      but also do cause OOM due to the RCU implementation.
      
      This patch removes abort_creds() from cap_task_prctl() by calling
      prepare_creds() only when we need to modify it.
      Reported-by: NKevin Hao <haokexin@gmail.com>
      Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
      Reviewed-by: NPaul Moore <paul@paul-moore.com>
      Acked-by: NSerge E. Hallyn <serge.hallyn@ubuntu.com>
      Reviewed-by: NKees Cook <keescook@chromium.org>
      Signed-off-by: NJames Morris <james.l.morris@oracle.com>
      6d6f3328
  2. 23 7月, 2014 16 次提交
  3. 19 7月, 2014 15 次提交
  4. 18 7月, 2014 3 次提交
  5. 17 7月, 2014 3 次提交
    • M
      ima: define '.ima' as a builtin 'trusted' keyring · 7d2ce232
      Mimi Zohar 提交于
      Require all keys added to the IMA keyring be signed by an
      existing trusted key on the system trusted keyring.
      
      Changelog v6:
      - remove ifdef CONFIG_IMA_TRUSTED_KEYRING in C code - Dmitry
      - update Kconfig dependency and help
      - select KEYS_DEBUG_PROC_KEYS - Dmitry
      
      Changelog v5:
      - Move integrity_init_keyring() to init_ima() - Dmitry
      - reset keyring[id] on failure - Dmitry
      
      Changelog v1:
      - don't link IMA trusted keyring to user keyring
      
      Changelog:
      - define stub integrity_init_keyring() function (reported-by Fengguang Wu)
      - differentiate between regular and trusted keyring names.
      - replace printk with pr_info (D. Kasatkin)
      - only make the IMA keyring a trusted keyring (reported-by D. Kastatkin)
      - define stub integrity_init_keyring() definition based on
        CONFIG_INTEGRITY_SIGNATURE, not CONFIG_INTEGRITY_ASYMMETRIC_KEYS.
        (reported-by Jim Davis)
      Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
      Signed-off-by: NDmitry Kasatkin <d.kasatkin@samsung.com>
      Acked-by: NDavid Howells <dhowells@redhat.com>
      7d2ce232
    • D
      KEYS: validate certificate trust only with builtin keys · 32c4741c
      Dmitry Kasatkin 提交于
      Instead of allowing public keys, with certificates signed by any
      key on the system trusted keyring, to be added to a trusted keyring,
      this patch further restricts the certificates to those signed only by
      builtin keys on the system keyring.
      
      This patch defines a new option 'builtin' for the kernel parameter
      'keys_ownerid' to allow trust validation using builtin keys.
      
      Simplified Mimi's "KEYS: define an owner trusted keyring" patch
      
      Changelog v7:
      - rename builtin_keys to use_builtin_keys
      Signed-off-by: NDmitry Kasatkin <d.kasatkin@samsung.com>
      Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
      32c4741c
    • D
      KEYS: validate certificate trust only with selected key · ffb70f61
      Dmitry Kasatkin 提交于
      Instead of allowing public keys, with certificates signed by any
      key on the system trusted keyring, to be added to a trusted keyring,
      this patch further restricts the certificates to those signed by a
      particular key on the system keyring.
      
      This patch defines a new kernel parameter 'ca_keys' to identify the
      specific key which must be used for trust validation of certificates.
      
      Simplified Mimi's "KEYS: define an owner trusted keyring" patch.
      
      Changelog:
      - support for builtin x509 public keys only
      - export "asymmetric_keyid_match"
      - remove ifndefs MODULE
      - rename kernel boot parameter from keys_ownerid to ca_keys
      Signed-off-by: NDmitry Kasatkin <d.kasatkin@samsung.com>
      Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
      ffb70f61