summaryrefslogtreecommitdiff
path: root/net/unix
AgeCommit message (Collapse)AuthorFilesLines
2016-03-02unix_diag: fix incorrect sign extension in unix_lookup_by_inoDmitry V. Levin1-1/+1
[ Upstream commit b5f0549231ffb025337be5a625b0ff9f52b016f0 ] The value passed by unix_diag_get_exact to unix_lookup_by_ino has type __u32, but unix_lookup_by_ino's argument ino has type int, which is not a problem yet. However, when ino is compared with sock_i_ino return value of type unsigned long, ino is sign extended to signed long, and this results to incorrect comparison on 64-bit architectures for inode numbers greater than INT_MAX. This bug was found by strace test suite. Fixes: 5d3cae8bc39d ("unix_diag: Dumping exact socket core") Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-03-02af_unix: Guard against other == sk in unix_dgram_sendmsgRainer Weikusat1-1/+6
[ Upstream commit a5527dda344fff0514b7989ef7a755729769daa1 ] The unix_dgram_sendmsg routine use the following test if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) { to determine if sk and other are in an n:1 association (either established via connect or by using sendto to send messages to an unrelated socket identified by address). This isn't correct as the specified address could have been bound to the sending socket itself or because this socket could have been connected to itself by the time of the unix_peer_get but disconnected before the unix_state_lock(other). In both cases, the if-block would be entered despite other == sk which might either block the sender unintentionally or lead to trying to unlock the same spin lock twice for a non-blocking send. Add a other != sk check to guard against this. Fixes: 7d267278a9ec ("unix: avoid use-after-free in ep_remove_wait_queue") Reported-By: Philipp Hahn <pmhahn@pmhahn.de> Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Tested-by: Philipp Hahn <pmhahn@pmhahn.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-03-02af_unix: fix struct pid memory leakEric Dumazet1-0/+1
[ Upstream commit fa0dc04df259ba2df3ce1920e9690c7842f8fa4b ] Dmitry reported a struct pid leak detected by a syzkaller program. Bug happens in unix_stream_recvmsg() when we break the loop when a signal is pending, without properly releasing scm. Fixes: b3ca9b02b007 ("net: fix multithreaded signal handling in unix recv routines") Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2016-01-05af_unix: Revert 'lock_interruptible' in stream receive codeRainer Weikusat1-10/+3
[ Upstream commit 3822b5c2fc62e3de8a0f33806ff279fb7df92432 ] With b3ca9b02b00704053a38bfe4c31dbbb9c13595d0, the AF_UNIX SOCK_STREAM receive code was changed from using mutex_lock(&u->readlock) to mutex_lock_interruptible(&u->readlock) to prevent signals from being delayed for an indefinite time if a thread sleeping on the mutex happened to be selected for handling the signal. But this was never a problem with the stream receive code (as opposed to its datagram counterpart) as that never went to sleep waiting for new messages with the mutex held and thus, wouldn't cause secondary readers to block on the mutex waiting for the sleeping primary reader. As the interruptible locking makes the code more complicated in exchange for no benefit, change it back to using mutex_lock. Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-12-15unix: avoid use-after-free in ep_remove_wait_queueRainer Weikusat1-19/+164
[ Upstream commit 7d267278a9ece963d77eefec61630223fce08c6c ] Rainer Weikusat <rweikusat@mobileactivedefense.com> writes: An AF_UNIX datagram socket being the client in an n:1 association with some server socket is only allowed to send messages to the server if the receive queue of this socket contains at most sk_max_ack_backlog datagrams. This implies that prospective writers might be forced to go to sleep despite none of the message presently enqueued on the server receive queue were sent by them. In order to ensure that these will be woken up once space becomes again available, the present unix_dgram_poll routine does a second sock_poll_wait call with the peer_wait wait queue of the server socket as queue argument (unix_dgram_recvmsg does a wake up on this queue after a datagram was received). This is inherently problematic because the server socket is only guaranteed to remain alive for as long as the client still holds a reference to it. In case the connection is dissolved via connect or by the dead peer detection logic in unix_dgram_sendmsg, the server socket may be freed despite "the polling mechanism" (in particular, epoll) still has a pointer to the corresponding peer_wait queue. There's no way to forcibly deregister a wait queue with epoll. Based on an idea by Jason Baron, the patch below changes the code such that a wait_queue_t belonging to the client socket is enqueued on the peer_wait queue of the server whenever the peer receive queue full condition is detected by either a sendmsg or a poll. A wake up on the peer queue is then relayed to the ordinary wait queue of the client socket via wake function. The connection to the peer wait queue is again dissolved if either a wake up is about to be relayed or the client socket reconnects or a dead peer is detected or the client socket is itself closed. This enables removing the second sock_poll_wait from unix_dgram_poll, thus avoiding the use-after-free, while still ensuring that no blocked writer sleeps forever. Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Fixes: ec0d215f9420 ("af_unix: fix 'poll for write'/connected DGRAM sockets") Reviewed-by: Jason Baron <jbaron@akamai.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-10-28net/unix: fix logic about sk_peek_offsetAndrey Vagin1-5/+7
[ Upstream commit e9193d60d363e4dff75ff6d43a48f22be26d59c7 ] Now send with MSG_PEEK can return data from multiple SKBs. Unfortunately we take into account the peek offset for each skb, that is wrong. We need to apply the peek offset only once. In addition, the peek offset should be used only if MSG_PEEK is set. Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Aaron Conole <aconole@bytheb.org> Fixes: 9f389e35674f ("af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag") Signed-off-by: Andrey Vagin <avagin@openvz.org> Tested-by: Aaron Conole <aconole@bytheb.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-10-28af_unix: return data from multiple SKBs on recv() with MSG_PEEK flagAaron Conole1-1/+13
[ Upstream commit 9f389e35674f5b086edd70ed524ca0f287259725 ] AF_UNIX sockets now return multiple skbs from recv() when MSG_PEEK flag is set. This is referenced in kernel bugzilla #12323 @ https://bugzilla.kernel.org/show_bug.cgi?id=12323 As described both in the BZ and lkml thread @ http://lkml.org/lkml/2008/1/8/444 calling recv() with MSG_PEEK on an AF_UNIX socket only reads a single skb, where the desired effect is to return as much skb data has been queued, until hitting the recv buffer size (whichever comes first). The modified MSG_PEEK path will now move to the next skb in the tree and jump to the again: label, rather than following the natural loop structure. This requires duplicating some of the loop head actions. This was tested using the python socketpair python code attached to the bugzilla issue. Signed-off-by: Aaron Conole <aconole@bytheb.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2015-06-10unix/caif: sk_socket can disappear when state is unlockedMark Salyzyn1-0/+8
[ Upstream commit b48732e4a48d80ed4a14812f0bab09560846514e ] got a rare NULL pointer dereference in clear_bit Signed-off-by: Mark Salyzyn <salyzyn@android.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> ---- v2: switch to sock_flag(sk, SOCK_DEAD) and added net/caif/caif_socket.c v3: return -ECONNRESET in upstream caller of wait function for SOCK_DEAD Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-04-18net: unix: non blocking recvmsg() should not return -EINTREric Dumazet1-5/+12
[ Upstream commit de1443916791d75fdd26becb116898277bb0273f ] Some applications didn't expect recvmsg() on a non blocking socket could return -EINTR. This possibility was added as a side effect of commit b3ca9b02b00704 ("net: fix multithreaded signal handling in unix recv routines"). To hit this bug, you need to be a bit unlucky, as the u->readlock mutex is usually held for very small periods. Fixes: b3ca9b02b00704 ("net: fix multithreaded signal handling in unix recv routines") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-03-24net: unix socket code abuses csum_partialAnton Blanchard1-2/+1
commit 0a13404dd3bf4ea870e3d96270b5a382edca85c0 upstream. The unix socket code is using the result of csum_partial to hash into a lookup table: unix_hash_fold(csum_partial(sunaddr, len, 0)); csum_partial is only guaranteed to produce something that can be folded into a checksum, as its prototype explains: * returns a 32-bit number suitable for feeding into itself * or csum_tcpudp_magic The 32bit value should not be used directly. Depending on the alignment, the ppc64 csum_partial will return different 32bit partial checksums that will fold into the same 16bit checksum. This difference causes the following testcase (courtesy of Gustavo) to sometimes fail: #include <sys/socket.h> #include <stdio.h> int main() { int fd = socket(PF_LOCAL, SOCK_STREAM|SOCK_CLOEXEC, 0); int i = 1; setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &i, 4); struct sockaddr addr; addr.sa_family = AF_LOCAL; bind(fd, &addr, 2); listen(fd, 128); struct sockaddr_storage ss; socklen_t sslen = (socklen_t)sizeof(ss); getsockname(fd, (struct sockaddr*)&ss, &sslen); fd = socket(PF_LOCAL, SOCK_STREAM|SOCK_CLOEXEC, 0); if (connect(fd, (struct sockaddr*)&ss, sslen) == -1){ perror(NULL); return 1; } printf("OK\n"); return 0; } As suggested by davem, fix this by using csum_fold to fold the partial 32bit checksum into a 16bit checksum before using it. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
2014-01-16net: unix: allow bind to fail on mutex lockSasha Levin1-2/+6
[ Upstream commit 37ab4fa7844a044dc21fde45e2a0fc2f3c3b6490 ] This is similar to the set_peek_off patch where calling bind while the socket is stuck in unix_dgram_recvmsg() will block and cause a hung task spew after a while. This is also the last place that did a straightforward mutex_lock(), so there shouldn't be any more of these patches. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-16net: unix: allow set_peek_off to failSasha Levin1-2/+6
[ Upstream commit 12663bfc97c8b3fdb292428105dd92d563164050 ] unix_dgram_recvmsg() will hold the readlock of the socket until recv is complete. In the same time, we may try to setsockopt(SO_PEEK_OFF) which will hang until unix_dgram_recvmsg() will complete (which can take a while) without allowing us to break out of it, triggering a hung task spew. Instead, allow set_peek_off to fail, this way userspace will not hang. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-08net: rework recvmsg handler msg_name and msg_namelen logicHannes Frederic Sowa1-5/+0
[ Upstream commit f3d3342602f8bcbf37d7c46641cb9bca7618eb1c ] 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 <davem@davemloft.net> Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-20net: unix: inherit SOCK_PASS{CRED, SEC} flags from socket to fix raceDaniel Borkmann1-0/+10
In the case of credentials passing in unix stream sockets (dgram sockets seem not affected), we get a rather sparse race after commit 16e5726 ("af_unix: dont send SCM_CREDENTIALS by default"). We have a stream server on receiver side that requests credential passing from senders (e.g. nc -U). Since we need to set SO_PASSCRED on each spawned/accepted socket on server side to 1 first (as it's not inherited), it can happen that in the time between accept() and setsockopt() we get interrupted, the sender is being scheduled and continues with passing data to our receiver. At that time SO_PASSCRED is neither set on sender nor receiver side, hence in cmsg's SCM_CREDENTIALS we get eventually pid:0, uid:65534, gid:65534 (== overflow{u,g}id) instead of what we actually would like to see. On the sender side, here nc -U, the tests in maybe_add_creds() invoked through unix_stream_sendmsg() would fail, as at that exact time, as mentioned, the sender has neither SO_PASSCRED on his side nor sees it on the server side, and we have a valid 'other' socket in place. Thus, sender believes it would just look like a normal connection, not needing/requesting SO_PASSCRED at that time. As reverting 16e5726 would not be an option due to the significant performance regression reported when having creds always passed, one way/trade-off to prevent that would be to set SO_PASSCRED on the listener socket and allow inheriting these flags to the spawned socket on server side in accept(). It seems also logical to do so if we'd tell the listener socket to pass those flags onwards, and would fix the race. Before, strace: recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"blub\n", 4096}], msg_controllen=32, {cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS{pid=0, uid=65534, gid=65534}}, msg_flags=0}, 0) = 5 After, strace: recvmsg(4, {msg_name(0)=NULL, msg_iov(1)=[{"blub\n", 4096}], msg_controllen=32, {cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS{pid=11580, uid=1000, gid=1000}}, msg_flags=0}, 0) = 5 Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-03unix_diag: fix info leakMathias Krause1-0/+1
When filling the netlink message we miss to wipe the pad field, therefore leak one byte of heap memory to userland. Fix this by setting pad to 0. Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-12af_unix: fix bug on large send()Eric Dumazet1-1/+2
commit e370a723632 ("af_unix: improve STREAM behavior with fragmented memory") added a bug on large send() because the skb_copy_datagram_from_iovec() call always start from the beginning of iovec. We must instead use the @sent variable to properly skip the already processed part. Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-10net: attempt high order allocations in sock_alloc_send_pskb()Eric Dumazet1-2/+4
Adding paged frags skbs to af_unix sockets introduced a performance regression on large sends because of additional page allocations, even if each skb could carry at least 100% more payload than before. We can instruct sock_alloc_send_pskb() to attempt high order allocations. Most of the time, it does a single page allocation instead of 8. I added an additional parameter to sock_alloc_send_pskb() to let other users to opt-in for this new feature on followup patches. Tested: Before patch : $ netperf -t STREAM_STREAM STREAM STREAM TEST Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 2304 212992 212992 10.00 46861.15 After patch : $ netperf -t STREAM_STREAM STREAM STREAM TEST Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 2304 212992 212992 10.00 57981.11 Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-10af_unix: improve STREAM behavior with fragmented memoryEric Dumazet1-35/+30
unix_stream_sendmsg() currently uses order-2 allocations, and we had numerous reports this can fail. The __GFP_REPEAT flag present in sock_alloc_send_pskb() is not helping. This patch extends the work done in commit eb6a24816b247c ("af_unix: reduce high order page allocations) for datagram sockets. This opens the possibility of zero copy IO (splice() and friends) The trick is to not use skb_pull() anymore in recvmsg() path, and instead add a @consumed field in UNIXCB() to track amount of already read payload in the skb. There is a performance regression for large sends because of extra page allocations that will be addressed in a follow-up patch, allowing sock_alloc_send_pskb() to attempt high order page allocations. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds1-1/+1
Pull networking updates from David Miller: "This is a re-do of the net-next pull request for the current merge window. The only difference from the one I made the other day is that this has Eliezer's interface renames and the timeout handling changes made based upon your feedback, as well as a few bug fixes that have trickeled in. Highlights: 1) Low latency device polling, eliminating the cost of interrupt handling and context switches. Allows direct polling of a network device from socket operations, such as recvmsg() and poll(). Currently ixgbe, mlx4, and bnx2x support this feature. Full high level description, performance numbers, and design in commit 0a4db187a999 ("Merge branch 'll_poll'") From Eliezer Tamir. 2) With the routing cache removed, ip_check_mc_rcu() gets exercised more than ever before in the case where we have lots of multicast addresses. Use a hash table instead of a simple linked list, from Eric Dumazet. 3) Add driver for Atheros CQA98xx 802.11ac wireless devices, from Bartosz Markowski, Janusz Dziedzic, Kalle Valo, Marek Kwaczynski, Marek Puzyniak, Michal Kazior, and Sujith Manoharan. 4) Support reporting the TUN device persist flag to userspace, from Pavel Emelyanov. 5) Allow controlling network device VF link state using netlink, from Rony Efraim. 6) Support GRE tunneling in openvswitch, from Pravin B Shelar. 7) Adjust SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF for modern times, from Daniel Borkmann and Eric Dumazet. 8) Allow controlling of TCP quickack behavior on a per-route basis, from Cong Wang. 9) Several bug fixes and improvements to vxlan from Stephen Hemminger, Pravin B Shelar, and Mike Rapoport. In particular, support receiving on multiple UDP ports. 10) Major cleanups, particular in the area of debugging and cookie lifetime handline, to the SCTP protocol code. From Daniel Borkmann. 11) Allow packets to cross network namespaces when traversing tunnel devices. From Nicolas Dichtel. 12) Allow monitoring netlink traffic via AF_PACKET sockets, in a manner akin to how we monitor real network traffic via ptype_all. From Daniel Borkmann. 13) Several bug fixes and improvements for the new alx device driver, from Johannes Berg. 14) Fix scalability issues in the netem packet scheduler's time queue, by using an rbtree. From Eric Dumazet. 15) Several bug fixes in TCP loss recovery handling, from Yuchung Cheng. 16) Add support for GSO segmentation of MPLS packets, from Simon Horman. 17) Make network notifiers have a real data type for the opaque pointer that's passed into them. Use this to properly handle network device flag changes in arp_netdev_event(). From Jiri Pirko and Timo Teräs. 18) Convert several drivers over to module_pci_driver(), from Peter Huewe. 19) tcp_fixup_rcvbuf() can loop 500 times over loopback, just use a O(1) calculation instead. From Eric Dumazet. 20) Support setting of explicit tunnel peer addresses in ipv6, just like ipv4. From Nicolas Dichtel. 21) Protect x86 BPF JIT against spraying attacks, from Eric Dumazet. 22) Prevent a single high rate flow from overruning an individual cpu during RX packet processing via selective flow shedding. From Willem de Bruijn. 23) Don't use spinlocks in TCP md5 signing fast paths, from Eric Dumazet. 24) Don't just drop GSO packets which are above the TBF scheduler's burst limit, chop them up so they are in-bounds instead. Also from Eric Dumazet. 25) VLAN offloads are missed when configured on top of a bridge, fix from Vlad Yasevich. 26) Support IPV6 in ping sockets. From Lorenzo Colitti. 27) Receive flow steering targets should be updated at poll() time too, from David Majnemer. 28) Fix several corner case regressions in PMTU/redirect handling due to the routing cache removal, from Timo Teräs. 29) We have to be mindful of ipv4 mapped ipv6 sockets in upd_v6_push_pending_frames(). From Hannes Frederic Sowa. 30) Fix L2TP sequence number handling bugs, from James Chapman." * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1214 commits) drivers/net: caif: fix wrong rtnl_is_locked() usage drivers/net: enic: release rtnl_lock on error-path vhost-net: fix use-after-free in vhost_net_flush net: mv643xx_eth: do not use port number as platform device id net: sctp: confirm route during forward progress virtio_net: fix race in RX VQ processing virtio: support unlocked queue poll net/cadence/macb: fix bug/typo in extracting gem_irq_read_clear bit Documentation: Fix references to defunct linux-net@vger.kernel.org net/fs: change busy poll time accounting net: rename low latency sockets functions to busy poll bridge: fix some kernel warning in multicast timer sfc: Fix memory leak when discarding scattered packets sit: fix tunnel update via netlink dt:net:stmmac: Add dt specific phy reset callback support. dt:net:stmmac: Add support to dwmac version 3.610 and 3.710 dt:net:stmmac: Allocate platform data only if its NULL. net:stmmac: fix memleak in the open method ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available net: ipv6: fix wrong ping_v6_sendmsg return value ...
2013-06-13net: Convert uses of typedef ctl_table to struct ctl_tableJoe Perches1-1/+1
Reduce the uses of this unnecessary typedef. Done via perl script: $ git grep --name-only -w ctl_table net | \ xargs perl -p -i -e '\ sub trim { my ($local) = @_; $local =~ s/(^\s+|\s+$)//g; return $local; } \ s/\b(?<!struct\s)ctl_table\b(\s*\*\s*|\s+\w+)/"struct ctl_table " . trim($1)/ge' Reflow the modified lines that now exceed 80 columns. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-05-12af_unix: use freezable blocking calls in readColin Cross1-1/+2
Avoid waking up every thread sleeping in read call on an AF_UNIX socket during suspend and resume by calling a freezable blocking call. Previous patches modified the freezer to avoid sending wakeups to threads that are blocked in freezable blocking calls. This call was selected to be converted to a freezable call because it doesn't hold any locks or release any resources when interrupted that might be needed by another freezing task or a kernel driver during suspend, and is a common site where idle userspace tasks are blocked. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-01af_unix: fix a fatal race with bit fieldsEric Dumazet1-6/+6
Using bit fields is dangerous on ppc64/sparc64, as the compiler [1] uses 64bit instructions to manipulate them. If the 64bit word includes any atomic_t or spinlock_t, we can lose critical concurrent changes. This is happening in af_unix, where unix_sk(sk)->gc_candidate/ gc_maybe_cycle/lock share the same 64bit word. This leads to fatal deadlock, as one/several cpus spin forever on a spinlock that will never be available again. A safer way would be to use a long to store flags. This way we are sure compiler/arch wont do bad things. As we own unix_gc_lock spinlock when clearing or setting bits, we can use the non atomic __set_bit()/__clear_bit(). recursion_level can share the same 64bit location with the spinlock, as it is set only with this spinlock held. [1] bug fixed in gcc-4.8.0 : http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52080 Reported-by: Ambrose Feinstein <ambrose@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-13/+12
Conflicts: drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c drivers/net/ethernet/emulex/benet/be.h include/net/tcp.h net/mac802154/mac802154.h Most conflicts were minor overlapping stuff. The be2net driver brought in some fixes that added __vlan_put_tag calls, which in net-next take an additional argument. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-30unix/stream: fix peeking with an offset larger than data in queueBenjamin Poirier1-13/+12
Currently, peeking on a unix stream socket with an offset larger than len of the data in the sk receive queue returns immediately with bogus data. This patch fixes this so that the behavior is the same as peeking with no offset on an empty queue: the caller blocks. Signed-off-by: Benjamin Poirier <bpoirier@suse.de> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-1/+1
Conflicts: drivers/net/ethernet/emulex/benet/be_main.c drivers/net/ethernet/intel/igb/igb_main.c drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c include/net/scm.h net/batman-adv/routing.c net/ipv4/tcp_input.c The e{uid,gid} --> {uid,gid} credentials fix conflicted with the cleanup in net-next to now pass cred structs around. The be2net driver had a bug fix in 'net' that overlapped with the VLAN interface changes by Patrick McHardy in net-next. An IGB conflict existed because in 'net' the build_skb() support was reverted, and in 'net-next' there was a comment style fix within that code. Several batman-adv conflicts were resolved by making sure that all calls to batadv_is_my_mac() are changed to have a new bat_priv first argument. Eric Dumazet's TS ECR fix in TCP in 'net' conflicted with the F-RTO rewrite in 'net-next', mostly overlapping changes. Thanks to Stephen Rothwell and Antonio Quartulli for help with several of these merge resolutions. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-08scm: Stop passing struct credEric W. Biederman1-8/+8
Now that uids and gids are completely encapsulated in kuid_t and kgid_t we no longer need to pass struct cred which allowed us to test both the uid and the user namespace for equality. Passing struct cred potentially allows us to pass the entire group list as BSD does but I don't believe the cost of cache line misses justifies retaining code for a future potential application. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-3/+3
Conflicts: drivers/nfc/microread/mei.c net/netfilter/nfnetlink_queue_core.c Pull in 'net' to get Eric Biederman's AF_UNIX fix, upon which some cleanups are going to go on-top. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-05af_unix: If we don't care about credentials coallesce all messagesEric W. Biederman1-1/+1
It was reported that the following LSB test case failed https://lsbbugs.linuxfoundation.org/attachment.cgi?id=2144 because we were not coallescing unix stream messages when the application was expecting us to. The problem was that the first send was before the socket was accepted and thus sock->sk_socket was NULL in maybe_add_creds, and the second send after the socket was accepted had a non-NULL value for sk->socket and thus we could tell the credentials were not needed so we did not bother. The unnecessary credentials on the first message cause unix_stream_recvmsg to start verifying that all messages had the same credentials before coallescing and then the coallescing failed because the second message had no credentials. Ignoring credentials when we don't care in unix_stream_recvmsg fixes a long standing pessimization which would fail to coallesce messages when reading from a unix stream socket if the senders were different even if we did not care about their credentials. I have tested this and verified that the in the LSB test case mentioned above that the messages do coallesce now, while the were failing to coallesce without this change. Reported-by: Karel Srot <ksrot@redhat.com> Reported-by: Ding Tianhong <dingtianhong@huawei.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-05Revert "af_unix: dont send SCM_CREDENTIAL when dest socket is NULL"Eric W. Biederman1-2/+2
This reverts commit 14134f6584212d585b310ce95428014b653dfaf6. The problem that the above patch was meant to address is that af_unix messages are not being coallesced because we are sending unnecesarry credentials. Not sending credentials in maybe_add_creds totally breaks unconnected unix domain sockets that wish to send credentails to other sockets. In practice this break some versions of udev because they receive a message and the sending uid is bogus so they drop the message. Reported-by: Sven Joachim <svenjoac@gmx.de> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-03net: fix smatch warnings inside datagram_pollJacob Keller1-1/+1
Commit 7d4c04fc170087119727119074e72445f2bb192b ("net: add option to enable error queue packets waking select") has an issue due to operator precedence causing the bit-wise OR to bind to the sock_flags call instead of the result of the terniary conditional. This fixes the *_poll functions to work properly. The old code results in "mask |= POLLPRI" instead of what was intended, which is to only include POLLPRI when the socket option is enabled. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-01net: add option to enable error queue packets waking selectKeller, Jacob E1-1/+3
Currently, when a socket receives something on the error queue it only wakes up the socket on select if it is in the "read" list, that is the socket has something to read. It is useful also to wake the socket if it is in the error list, which would enable software to wait on error queue packets without waking up for regular data on the socket. The main use case is for receiving timestamped transmit packets which return the timestamp to the socket via the error queue. This enables an application to select on the socket for the error queue only instead of for the regular traffic. -v2- * Added the SO_SELECT_ERR_QUEUE socket option to every architechture specific file * Modified every socket poll function that checks error queue Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Cc: Jeffrey Kirsher <jeffrey.t.kirsher@intel.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Matthew Vick <matthew.vick@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-26af_unix: dont send SCM_CREDENTIAL when dest socket is NULLdingtianhong1-2/+2
SCM_SCREDENTIALS should apply to write() syscalls only either source or destination socket asserted SOCK_PASSCRED. The original implememtation in maybe_add_creds is wrong, and breaks several LSB testcases ( i.e. /tset/LSB.os/netowkr/recvfrom/T.recvfrom). Origionally-authored-by: Karel Srot <ksrot@redhat.com> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-25unix: fix a race condition in unix_release()Paul Moore1-4/+3
As reported by Jan, and others over the past few years, there is a race condition caused by unix_release setting the sock->sk pointer to NULL before properly marking the socket as dead/orphaned. This can cause a problem with the LSM hook security_unix_may_send() if there is another socket attempting to write to this partially released socket in between when sock->sk is set to NULL and it is marked as dead/orphaned. This patch fixes this by only setting sock->sk to NULL after the socket has been marked as dead; I also take the opportunity to make unix_release_sock() a void function as it only ever returned 0/success. Dave, I think this one should go on the -stable pile. Special thanks to Jan for coming up with a reproducer for this problem. Reported-by: Jan Stancek <jan.stancek@gmail.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-02-28hlist: drop the node parameter from iteratorsSasha Levin2-9/+4
I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...
2013-02-23new helper: file_inode(file)Al Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-18net: proc: change proc_net_remove to remove_proc_entryGao feng1-1/+1
proc_net_remove is only used to remove proc entries that under /proc/net,it's not a general function for removing proc entries of netns. if we want to remove some proc entries which under /proc/net/stat/, we still need to call remove_proc_entry. this patch use remove_proc_entry to replace proc_net_remove. we can remove proc_net_remove after this patch. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-02-18net: proc: change proc_net_fops_create to proc_createGao feng1-1/+1
Right now, some modules such as bonding use proc_create to create proc entries under /proc/net/, and other modules such as ipv4 use proc_net_fops_create. It looks a little chaos.this patch changes all of proc_net_fops_create to proc_create. we can remove proc_net_fops_create after this patch. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-10unix: Use FIELD_SIZEOF() in af_unix_init().YOSHIFUJI Hideaki / 吉藤英明1-2/+1
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-19net: Don't export sysctls to unprivileged usersEric W. Biederman1-0/+4
In preparation for supporting the creation of network namespaces by unprivileged users, modify all of the per net sysctl exports and refuse to allow them to unprivileged users. This makes it safe for unprivileged users in general to access per net sysctls, and allows sysctls to be exported to unprivileged users on an individual basis as they are deemed safe. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-23sock-diag: Report shutdown for inet and unix sockets (v2)Pavel Emelyanov1-0/+3
Make it simple -- just put new nlattr with just sk->sk_shutdown bits. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-17af_unix: old_cred is surplusAlan Cox1-4/+1
Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-10netlink: Rename pid to portid to avoid confusionEric W. Biederman1-7/+7
It is a frequent mistake to confuse the netlink port identifier with a process identifier. Try to reduce this confusion by renaming fields that hold port identifiers portid instead of pid. I have carefully avoided changing the structures exported to userspace to avoid changing the userspace API. I have successfully built an allyesconfig kernel with this change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31af_unix: fix shutdown parameter checkingXi Wang1-4/+8
Return -EINVAL rather than 0 given an invalid "mode" parameter. Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-22af_netlink: force credentials passing [CVE-2012-3520]Eric Dumazet1-2/+2
Pablo Neira Ayuso discovered that avahi and potentially NetworkManager accept spoofed Netlink messages because of a kernel bug. The kernel passes all-zero SCM_CREDENTIALS ancillary data to the receiver if the sender did not provide such data, instead of not including any such data at all or including the correct data from the peer (as it is the case with AF_UNIX). This bug was introduced in commit 16e572626961 (af_unix: dont send SCM_CREDENTIALS by default) This patch forces passing credentials for netlink, as before the regression. Another fix would be to not add SCM_CREDENTIALS in netlink messages if not provided by the sender, but it might break some programs. With help from Florian Weimer & Petr Matousek This issue is designated as CVE-2012-3520 Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Petr Matousek <pmatouse@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-01Merge branch 'for-linus' of ↵Linus Torvalds1-50/+43
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull second vfs pile from Al Viro: "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the deadlock reproduced by xfstests 068), symlink and hardlink restriction patches, plus assorted cleanups and fixes. Note that another fsfreeze deadlock (emergency thaw one) is *not* dealt with - the series by Fernando conflicts a lot with Jan's, breaks userland ABI (FIFREEZE semantics gets changed) and trades the deadlock for massive vfsmount leak; this is going to be handled next cycle. There probably will be another pull request, but that stuff won't be in it." Fix up trivial conflicts due to unrelated changes next to each other in drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c} * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits) delousing target_core_file a bit Documentation: Correct s_umount state for freeze_fs/unfreeze_fs fs: Remove old freezing mechanism ext2: Implement freezing btrfs: Convert to new freezing mechanism nilfs2: Convert to new freezing mechanism ntfs: Convert to new freezing mechanism fuse: Convert to new freezing mechanism gfs2: Convert to new freezing mechanism ocfs2: Convert to new freezing mechanism xfs: Convert to new freezing code ext4: Convert to new freezing mechanism fs: Protect write paths by sb_start_write - sb_end_write fs: Skip atime update on frozen filesystem fs: Add freezing handling to mnt_want_write() / mnt_drop_write() fs: Improve filesystem freezing handling switch the protection of percpu_counter list to spinlock nfsd: Push mnt_want_write() outside of i_mutex btrfs: Push mnt_want_write() outside of i_mutex fat: Push mnt_want_write() outside of i_mutex ...
2012-07-29clean unix_bind() up a bitAl Viro1-45/+43
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-29pull mnt_want_write()/mnt_drop_write() into ↵Al Viro1-4/+0
kern_path_create()/done_path_create() resp. One side effect - attempt to create a cross-device link on a read-only fs fails with EROFS instead of EXDEV now. Makes more sense, POSIX allows, etc. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-29new helper: done_path_create()Al Viro1-5/+4
releases what needs to be released after {kern,user}_path_create() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-17net: make sock diag per-namespaceAndrey Vagin1-2/+7
Before this patch sock_diag works for init_net only and dumps information about sockets from all namespaces. This patch expands sock_diag for all name-spaces. It creates a netlink kernel socket for each netns and filters data during dumping. v2: filter accoding with netns in all places remove an unused variable. Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Pavel Emelyanov <xemul@parallels.com> CC: Eric Dumazet <eric.dumazet@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Andrew Vagin <avagin@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>