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  1. 12 7月, 2007 1 次提交
    • M
      [AF_UNIX]: Rewrite garbage collector, fixes race. · 1fd05ba5
      由 Miklos Szeredi 提交于 
      Throw out the old mark & sweep garbage collector and put in a
refcounting cycle detecting one.

The old one had a race with recvmsg, that resulted in false positives
and hence data loss.  The old algorithm operated on all unix sockets
in the system, so any additional locking would have meant performance
problems for all users of these.

The new algorithm instead only operates on "in flight" sockets, which
are very rare, and the additional locking for these doesn't negatively
impact the vast majority of users.

In fact it's probable, that there weren't *any* heavy senders of
sockets over sockets, otherwise the above race would have been
discovered long ago.

The patch works OK with the app that exposed the race with the old
code.  The garbage collection has also been verified to work in a few
simple cases.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1fd05ba5
  3. 11 7月, 2007 1 次提交
  5. 08 6月, 2007 1 次提交
    • M
      [AF_UNIX]: Fix stream recvmsg() race. · 3c0d2f37
      由 Miklos Szeredi 提交于 
      A recv() on an AF_UNIX, SOCK_STREAM socket can race with a
send()+close() on the peer, causing recv() to return zero, even though
the sent data should be received.

This happens if the send() and the close() is performed between
skb_dequeue() and checking sk->sk_shutdown in unix_stream_recvmsg():

process A  skb_dequeue() returns NULL, there's no data in the socket queue
process B  new data is inserted onto the queue by unix_stream_sendmsg()
process B  sk->sk_shutdown is set to SHUTDOWN_MASK by unix_release_sock()
process A  sk->sk_shutdown is checked, unix_release_sock() returns zero

I'm surprised nobody noticed this, it's not hard to trigger.  Maybe
it's just (un)luck with the timing.

It's possible to work around this bug in userspace, by retrying the
recv() once in case of a zero return value.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3c0d2f37
  7. 04 6月, 2007 2 次提交
    • D
      [AF_UNIX]: Fix datagram connect race causing an OOPS. · 278a3de5
      由 David S. Miller 提交于 
      Based upon an excellent bug report and initial patch by
Frederik Deweerdt.

The UNIX datagram connect code blindly dereferences other->sk_socket
via the call down to the security_unix_may_send() function.

Without locking 'other' that pointer can go NULL via unix_release_sock()
which does sock_orphan() which also marks the socket SOCK_DEAD.

So we have to lock both 'sk' and 'other' yet avoid all kinds of
potential deadlocks (connect to self is OK for datagram sockets and it
is possible for two datagram sockets to perform a simultaneous connect
to each other).  So what we do is have a "double lock" function similar
to how we handle this situation in other areas of the kernel.  We take
the lock of the socket pointer with the smallest address first in
order to avoid ABBA style deadlocks.

Once we have them both locked, we check to see if SOCK_DEAD is set
for 'other' and if so, drop everything and retry the lookup.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      278a3de5
    • D
      [AF_UNIX]: Make socket locking much less confusing. · 1c92b4e5
      由 David S. Miller 提交于 
      The unix_state_*() locking macros imply that there is some
rwlock kind of thing going on, but the implementation is
actually a spinlock which makes the code more confusing than
it needs to be.

So use plain unix_state_lock and unix_state_unlock.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1c92b4e5
  9. 09 5月, 2007 1 次提交
  11. 26 4月, 2007 1 次提交
  13. 07 3月, 2007 1 次提交
  15. 03 3月, 2007 1 次提交
  17. 13 2月, 2007 1 次提交
  19. 11 2月, 2007 1 次提交
  21. 03 12月, 2006 1 次提交
  23. 23 9月, 2006 2 次提交
  25. 03 8月, 2006 1 次提交
    • C
      [AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patch · dc49c1f9
      由 Catherine Zhang 提交于 
      From: Catherine Zhang <cxzhang@watson.ibm.com>

This patch implements a cleaner fix for the memory leak problem of the
original unix datagram getpeersec patch.  Instead of creating a
security context each time a unix datagram is sent, we only create the
security context when the receiver requests it.

This new design requires modification of the current
unix_getsecpeer_dgram LSM hook and addition of two new hooks, namely,
secid_to_secctx and release_secctx.  The former retrieves the security
context and the latter releases it.  A hook is required for releasing
the security context because it is up to the security module to decide
how that's done.  In the case of Selinux, it's a simple kfree
operation.
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      dc49c1f9
  27. 22 7月, 2006 1 次提交
  29. 04 7月, 2006 2 次提交
  31. 01 7月, 2006 1 次提交
  33. 30 6月, 2006 1 次提交
    • C
      [AF_UNIX]: Datagram getpeersec · 877ce7c1
      由 Catherine Zhang 提交于 
      This patch implements an API whereby an application can determine the
label of its peer's Unix datagram sockets via the auxiliary data mechanism of
recvmsg.

Patch purpose:

This patch enables a security-aware application to retrieve the
security context of the peer of a Unix datagram socket.  The application
can then use this security context to determine the security context for
processing on behalf of the peer who sent the packet.

Patch design and implementation:

The design and implementation is very similar to the UDP case for INET
sockets.  Basically we build upon the existing Unix domain socket API for
retrieving user credentials.  Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).  To retrieve the security
context, the application first indicates to the kernel such desire by
setting the SO_PASSSEC option via getsockopt.  Then the application
retrieves the security context using the auxiliary data mechanism.

An example server application for Unix datagram socket should look like this:

toggle = 1;
toggle_len = sizeof(toggle);

setsockopt(sockfd, SOL_SOCKET, SO_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
    cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
    if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
        cmsg_hdr->cmsg_level == SOL_SOCKET &&
        cmsg_hdr->cmsg_type == SCM_SECURITY) {
        memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
    }
}

sock_setsockopt is enhanced with a new socket option SOCK_PASSSEC to allow
a server socket to receive security context of the peer.

Testing:

We have tested the patch by setting up Unix datagram client and server
applications.  We verified that the server can retrieve the security context
using the auxiliary data mechanism of recvmsg.
Signed-off-by: NCatherine Zhang <cxzhang@watson.ibm.com>
Acked-by: NAcked-by: James Morris <jmorris@namei.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      877ce7c1
  35. 26 3月, 2006 1 次提交
    • D
      [PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications · f348d70a
      由 Davide Libenzi 提交于 
      Implement the half-closed devices notifiation, by adding a new POLLRDHUP
(and its alias EPOLLRDHUP) bit to the existing poll/select sets.  Since the
existing POLLHUP handling, that does not report correctly half-closed
devices, was feared to be changed, this implementation leaves the current
POLLHUP reporting unchanged and simply add a new bit that is set in the few
places where it makes sense.  The same thing was discussed and conceptually
agreed quite some time ago:

http://lkml.org/lkml/2003/7/12/116

Since this new event bit is added to the existing Linux poll infrastruture,
even the existing poll/select system calls will be able to use it.  As far
as the existing POLLHUP handling, the patch leaves it as is.  The
pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing
archs and sets the bit in the six relevant files.  The other attached diff
is the simple change required to sys/epoll.h to add the EPOLLRDHUP
definition.

There is "a stupid program" to test POLLRDHUP delivery here:

 http://www.xmailserver.org/pollrdhup-test.c

It tests poll(2), but since the delivery is same epoll(2) will work equally.
Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f348d70a
  37. 21 3月, 2006 2 次提交
  39. 09 3月, 2006 1 次提交
    • D
      [PATCH] fix file counting · 529bf6be
      由 Dipankar Sarma 提交于 
      I have benchmarked this on an x86_64 NUMA system and see no significant
performance difference on kernbench.  Tested on both x86_64 and powerpc.

The way we do file struct accounting is not very suitable for batched
freeing.  For scalability reasons, file accounting was
constructor/destructor based.  This meant that nr_files was decremented
only when the object was removed from the slab cache.  This is susceptible
to slab fragmentation.  With RCU based file structure, consequent batched
freeing and a test program like Serge's, we just speed this up and end up
with a very fragmented slab -

llm22:~ # cat /proc/sys/fs/file-nr
587730  0       758844

At the same time, I see only a 2000+ objects in filp cache.  The following
patch I fixes this problem.

This patch changes the file counting by removing the filp_count_lock.
Instead we use a separate percpu counter, nr_files, for now and all
accesses to it are through get_nr_files() api.  In the sysctl handler for
nr_files, we populate files_stat.nr_files before returning to user.

Counting files as an when they are created and destroyed (as opposed to
inside slab) allows us to correctly count open files with RCU.
Signed-off-by: NDipankar Sarma <dipankar@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      529bf6be
  41. 10 1月, 2006 1 次提交
  43. 04 1月, 2006 5 次提交
  45. 09 11月, 2005 1 次提交
  47. 30 8月, 2005 2 次提交
  49. 09 7月, 2005 1 次提交
  51. 20 5月, 2005 1 次提交
  53. 26 4月, 2005 2 次提交
    • A
      [NET]: kill gratitious includes of major.h · 5523662c
      由 Al Viro 提交于 
      	A lot of places in there are including major.h for no reason
whatsoever.  Removed.  And yes, it still builds.

	The history of that stuff is often amusing.  E.g. for net/core/sock.c
the story looks so, as far as I've been able to reconstruct it: we used to
need major.h in net/socket.c circa 1.1.early.  In 1.1.13 that need had
disappeared, along with register_chrdev(SOCKET_MAJOR, "socket", &net_fops)
in sock_init().  Include had not.  When 1.2 -> 1.3 reorg of net/* had moved
a lot of stuff from net/socket.c to net/core/sock.c, this crap had followed...
Signed-off-by: NAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      5523662c
    • A
      [PATCH] kill gratitious includes of major.h under net/* · b453257f
      由 Al Viro 提交于 
      A lot of places in there are including major.h for no reason whatsoever.
Removed.  And yes, it still builds. 

The history of that stuff is often amusing.  E.g.  for net/core/sock.c
the story looks so, as far as I've been able to reconstruct it: we used
to need major.h in net/socket.c circa 1.1.early.  In 1.1.13 that need
had disappeared, along with register_chrdev(SOCKET_MAJOR, "socket",
&net_fops) in sock_init().  Include had not.  When 1.2 -> 1.3 reorg of
net/* had moved a lot of stuff from net/socket.c to net/core/sock.c,
this crap had followed... 
Signed-off-by: NAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b453257f
  55. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4