linux-stable.git/net/compat.c, branch v3.14

x86, x32: Correct invalid use of user timespec in the kernel

2014-01-31T02:44:13+00:00

The x32 case for the recvmsg() timout handling is broken:

  asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
                                      unsigned int vlen, unsigned int flags,
                                      struct compat_timespec __user *timeout)
  {
          int datagrams;
          struct timespec ktspec;

          if (flags & MSG_CMSG_COMPAT)
                  return -EINVAL;

          if (COMPAT_USE_64BIT_TIME)
                  return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
                                        flags | MSG_CMSG_COMPAT,
                                        (struct timespec *) timeout);
          ...

The timeout pointer parameter is provided by userland (hence the __user
annotation) but for x32 syscalls it's simply cast to a kernel pointer
and is passed to __sys_recvmmsg which will eventually directly
dereference it for both reading and writing.  Other callers to
__sys_recvmmsg properly copy from userland to the kernel first.

The bug was introduced by commit ee4fa23c4bfc ("compat: Use
COMPAT_USE_64BIT_TIME in net/compat.c") and should affect all kernels
since 3.4 (and perhaps vendor kernels if they backported x32 support
along with this code).

Note that CONFIG_X86_X32_ABI gets enabled at build time and only if
CONFIG_X86_X32 is enabled and ld can build x32 executables.

Other uses of COMPAT_USE_64BIT_TIME seem fine.

This addresses CVE-2014-0038.

Signed-off-by: PaX Team 
Signed-off-by: H. Peter Anvin 
Cc:  # v3.4+
Signed-off-by: Linus Torvalds

net: clamp ->msg_namelen instead of returning an error

2013-11-29T21:12:52+00:00

If kmsg->msg_namelen > sizeof(struct sockaddr_storage) then in the
original code that would lead to memory corruption in the kernel if you
had audit configured.  If you didn't have audit configured it was
harmless.

There are some programs such as beta versions of Ruby which use too
large of a buffer and returning an error code breaks them.  We should
clamp the ->msg_namelen value instead.

Fixes: 1661bf364ae9 ("net: heap overflow in __audit_sockaddr()")
Reported-by: Eric Wong 
Signed-off-by: Dan Carpenter 
Tested-by: Eric Wong 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: rework recvmsg handler msg_name and msg_namelen logic

2013-11-21T02:52:30+00:00

This patch now always passes msg->msg_namelen as 0. recvmsg handlers must
set msg_namelen to the proper size <= sizeof(struct sockaddr_storage)
to return msg_name to the user.

This prevents numerous uninitialized memory leaks we had in the
recvmsg handlers and makes it harder for new code to accidentally leak
uninitialized memory.

Optimize for the case recvfrom is called with NULL as address. We don't
need to copy the address at all, so set it to NULL before invoking the
recvmsg handler. We can do so, because all the recvmsg handlers must
cope with the case a plain read() is called on them. read() also sets
msg_name to NULL.

Also document these changes in include/linux/net.h as suggested by David
Miller.

Changes since RFC:

Set msg->msg_name = NULL if user specified a NULL in msg_name but had a
non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't
affect sendto as it would bail out earlier while trying to copy-in the
address. It also more naturally reflects the logic by the callers of
verify_iovec.

With this change in place I could remove "
if (!uaddr || msg_sys->msg_namelen == 0)
	msg->msg_name = NULL
".

This change does not alter the user visible error logic as we ignore
msg_namelen as long as msg_name is NULL.

Also remove two unnecessary curly brackets in ___sys_recvmsg and change
comments to netdev style.

Cc: David Miller 
Suggested-by: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller

net: heap overflow in __audit_sockaddr()

2013-10-03T20:05:14+00:00

We need to cap ->msg_namelen or it leads to a buffer overflow when we
to the memcpy() in __audit_sockaddr().  It requires CAP_AUDIT_CONTROL to
exploit this bug.

The call tree is:
___sys_recvmsg()
  move_addr_to_user()
    audit_sockaddr()
      __audit_sockaddr()

Reported-by: Jüri Aedla 
Signed-off-by: Dan Carpenter 
Signed-off-by: David S. Miller

net: Unbreak compat_sys_{send,recv}msg

2013-06-06T18:52:14+00:00

I broke them in this commit:

    commit 1be374a0518a288147c6a7398792583200a67261
    Author: Andy Lutomirski 
    Date:   Wed May 22 14:07:44 2013 -0700

        net: Block MSG_CMSG_COMPAT in send(m)msg and recv(m)msg

This patch adds __sys_sendmsg and __sys_sendmsg as common helpers that accept
MSG_CMSG_COMPAT and blocks MSG_CMSG_COMPAT at the syscall entrypoints.  It
also reverts some unnecessary checks in sys_socketcall.

Apparently I was suffering from underscore blindness the first time around.

Signed-off-by: Andy Lutomirski 
Tested-by: Eric Dumazet 
Signed-off-by: David S. Miller

make get_file() return its argument

2012-09-27T01:10:25+00:00

simplifies a bunch of callers...

Signed-off-by: Al Viro

net: Fix references to out-of-scope variables in put_cmsg_compat()

2012-07-23T00:50:49+00:00

In net/compat.c::put_cmsg_compat() we may assign 'data' the address of
either the 'ctv' or 'cts' local variables inside the 'if
(!COMPAT_USE_64BIT_TIME)' branch.

Those variables go out of scope at the end of the 'if' statement, so
when we use 'data' further down in 'copy_to_user(CMSG_COMPAT_DATA(cm),
data, cmlen - sizeof(struct compat_cmsghdr))' there's no telling what
it may be refering to - not good.

Fix the problem by simply giving 'ctv' and 'cts' function scope.

Signed-off-by: Jesper Juhl 
Signed-off-by: David S. Miller

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2012-05-22T03:27:36+00:00

Pull security subsystem updates from James Morris:
 "New notable features:
   - The seccomp work from Will Drewry
   - PR_{GET,SET}_NO_NEW_PRIVS from Andy Lutomirski
   - Longer security labels for Smack from Casey Schaufler
   - Additional ptrace restriction modes for Yama by Kees Cook"

Fix up trivial context conflicts in arch/x86/Kconfig and include/linux/filter.h

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (65 commits)
  apparmor: fix long path failure due to disconnected path
  apparmor: fix profile lookup for unconfined
  ima: fix filename hint to reflect script interpreter name
  KEYS: Don't check for NULL key pointer in key_validate()
  Smack: allow for significantly longer Smack labels v4
  gfp flags for security_inode_alloc()?
  Smack: recursive tramsmute
  Yama: replace capable() with ns_capable()
  TOMOYO: Accept manager programs which do not start with / .
  KEYS: Add invalidation support
  KEYS: Do LRU discard in full keyrings
  KEYS: Permit in-place link replacement in keyring list
  KEYS: Perform RCU synchronisation on keys prior to key destruction
  KEYS: Announce key type (un)registration
  KEYS: Reorganise keys Makefile
  KEYS: Move the key config into security/keys/Kconfig
  KEYS: Use the compat keyctl() syscall wrapper on Sparc64 for Sparc32 compat
  Yama: remove an unused variable
  samples/seccomp: fix dependencies on arch macros
  Yama: add additional ptrace scopes
  ...

net: cleanup unsigned to unsigned int

2012-04-15T16:44:40+00:00

Use of "unsigned int" is preferred to bare "unsigned" in net tree.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net/compat.c,linux/filter.h: share compat_sock_fprog

2012-04-14T01:13:19+00:00

Any other users of bpf_*_filter that take a struct sock_fprog from
userspace will need to be able to also accept a compat_sock_fprog
if the arch supports compat calls.  This change allows the existing
compat_sock_fprog be shared.

Signed-off-by: Will Drewry 
Acked-by: Serge Hallyn 
Acked-by: Eric Dumazet 
Acked-by: Eric Paris 

v18: tasered by the apostrophe police
v14: rebase/nochanges
v13: rebase on to 88ebdda6159ffc15699f204c33feb3e431bf9bdc
v12: rebase on to linux-next
v11: introduction
Signed-off-by: James Morris