Commit Graph

11 Commits

Author SHA1 Message Date
Miklos Szeredi
1fd05ba5a2 [AF_UNIX]: Rewrite garbage collector, fixes race.
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: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-11 14:22:39 -07:00
David S. Miller
1c92b4e50e [AF_UNIX]: Make socket locking much less confusing.
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: David S. Miller <davem@davemloft.net>
2007-06-03 18:08:40 -07:00
Catherine Zhang
dc49c1f94e [AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patch
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:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-02 14:12:06 -07:00
Ingo Molnar
a09785a241 [PATCH] lockdep: annotate af_unix locking
Teach special (recursive) locking code to the lock validator.  Also splits
af_unix's sk_receive_queue.lock class from the other networking skb-queue
locks.  Has no effect on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:07 -07:00
Catherine Zhang
877ce7c1b3 [AF_UNIX]: Datagram getpeersec
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: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-29 16:58:06 -07:00
David Woodhouse
62c4f0a2d5 Don't include linux/config.h from anywhere else in include/
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-26 12:56:16 +01:00
Ingo Molnar
57b47a53ec [NET]: sem2mutex part 2
Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:35:41 -08:00
Benjamin LaHaise
fd19f329a3 [AF_UNIX]: Convert to use a spinlock instead of rwlock
From: Benjamin LaHaise <bcrl@kvack.org>

In af_unix, a rwlock is used to protect internal state.  At least on my 
P4 with HT it is faster to use a spinlock due to the simpler memory 
barrier used to unlock.  This patch raises bw_unix to ~690K/s.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 14:10:46 -08:00
David S. Miller
fbe9cc4a87 [AF_UNIX]: Use spinlock for unix_table_lock
This lock is actually taken mostly as a writer,
so using a rwlock actually just makes performance
worse especially on chips like the Intel P4.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:59 -08:00
Arnaldo Carvalho de Melo
20380731bc [NET]: Fix sparse warnings
Of this type, mostly:

CHECK   net/ipv6/netfilter.c
net/ipv6/netfilter.c:96:12: warning: symbol 'ipv6_netfilter_init' was not declared. Should it be static?
net/ipv6/netfilter.c:101:6: warning: symbol 'ipv6_netfilter_fini' was not declared. Should it be static?

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 16:01:32 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00