linux-toradex.git/net, branch v3.0.44

drop_monitor: dont sleep in atomic context

2012-10-02T16:47:42+00:00

commit bec4596b4e6770c7037f21f6bd27567b152dc0d6 upstream.

drop_monitor calls several sleeping functions while in atomic context.

 BUG: sleeping function called from invalid context at mm/slub.c:943
 in_atomic(): 1, irqs_disabled(): 0, pid: 2103, name: kworker/0:2
 Pid: 2103, comm: kworker/0:2 Not tainted 3.5.0-rc1+ #55
 Call Trace:
  [] __might_sleep+0xca/0xf0
  [] kmem_cache_alloc_node+0x1b3/0x1c0
  [] ? queue_delayed_work_on+0x11c/0x130
  [] __alloc_skb+0x4b/0x230
  [] ? reset_per_cpu_data+0x160/0x160 [drop_monitor]
  [] reset_per_cpu_data+0x2f/0x160 [drop_monitor]
  [] send_dm_alert+0x4b/0xb0 [drop_monitor]
  [] process_one_work+0x130/0x4c0
  [] worker_thread+0x159/0x360
  [] ? manage_workers.isra.27+0x240/0x240
  [] kthread+0x93/0xa0
  [] kernel_thread_helper+0x4/0x10
  [] ? kthread_freezable_should_stop+0x80/0x80
  [] ? gs_change+0xb/0xb

Rework the logic to call the sleeping functions in right context.

Use standard timer/workqueue api to let system chose any cpu to perform
the allocation and netlink send.

Also avoid a loop if reset_per_cpu_data() cannot allocate memory :
use mod_timer() to wait 1/10 second before next try.

Signed-off-by: Eric Dumazet 
Cc: Neil Horman 
Reviewed-by: Neil Horman 
Signed-off-by: David S. Miller 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

drop_monitor: prevent init path from scheduling on the wrong cpu

2012-10-02T16:47:42+00:00

commit 4fdcfa12843bca38d0c9deff70c8720e4e8f515f upstream.

I just noticed after some recent updates, that the init path for the drop
monitor protocol has a minor error.  drop monitor maintains a per cpu structure,
that gets initalized from a single cpu.  Normally this is fine, as the protocol
isn't in use yet, but I recently made a change that causes a failed skb
allocation to reschedule itself .  Given the current code, the implication is
that this workqueue reschedule will take place on the wrong cpu.  If drop
monitor is used early during the boot process, its possible that two cpus will
access a single per-cpu structure in parallel, possibly leading to data
corruption.

This patch fixes the situation, by storing the cpu number that a given instance
of this per-cpu data should be accessed from.  In the case of a need for a
reschedule, the cpu stored in the struct is assigned the rescheule, rather than
the currently executing cpu

Tested successfully by myself.

Signed-off-by: Neil Horman 
CC: David Miller 
Signed-off-by: David S. Miller 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

drop_monitor: Make updating data->skb smp safe

2012-10-02T16:47:42+00:00

commit 3885ca785a3618593226687ced84f3f336dc3860 upstream.

Eric Dumazet pointed out to me that the drop_monitor protocol has some holes in
its smp protections.  Specifically, its possible to replace data->skb while its
being written.  This patch corrects that by making data->skb an rcu protected
variable.  That will prevent it from being overwritten while a tracepoint is
modifying it.

Signed-off-by: Neil Horman 
Reported-by: Eric Dumazet 
CC: David Miller 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

drop_monitor: fix sleeping in invalid context warning

2012-10-02T16:47:42+00:00

commit cde2e9a651b76d8db36ae94cd0febc82b637e5dd upstream.

Eric Dumazet pointed out this warning in the drop_monitor protocol to me:

[   38.352571] BUG: sleeping function called from invalid context at kernel/mutex.c:85
[   38.352576] in_atomic(): 1, irqs_disabled(): 0, pid: 4415, name: dropwatch
[   38.352580] Pid: 4415, comm: dropwatch Not tainted 3.4.0-rc2+ #71
[   38.352582] Call Trace:
[   38.352592]  [] ? trace_napi_poll_hit+0xd0/0xd0
[   38.352599]  [] __might_sleep+0xca/0xf0
[   38.352606]  [] mutex_lock+0x26/0x50
[   38.352610]  [] ? trace_napi_poll_hit+0xd0/0xd0
[   38.352616]  [] tracepoint_probe_register+0x29/0x90
[   38.352621]  [] set_all_monitor_traces+0x105/0x170
[   38.352625]  [] net_dm_cmd_trace+0x2a/0x40
[   38.352630]  [] genl_rcv_msg+0x21a/0x2b0
[   38.352636]  [] ? zone_statistics+0x99/0xc0
[   38.352640]  [] ? genl_rcv+0x30/0x30
[   38.352645]  [] netlink_rcv_skb+0xa9/0xd0
[   38.352649]  [] genl_rcv+0x20/0x30
[   38.352653]  [] netlink_unicast+0x1ae/0x1f0
[   38.352658]  [] netlink_sendmsg+0x2b6/0x310
[   38.352663]  [] sock_sendmsg+0x10f/0x130
[   38.352668]  [] ? move_addr_to_kernel+0x60/0xb0
[   38.352673]  [] ? verify_iovec+0x64/0xe0
[   38.352677]  [] __sys_sendmsg+0x386/0x390
[   38.352682]  [] ? handle_mm_fault+0x139/0x210
[   38.352687]  [] ? do_page_fault+0x1ec/0x4f0
[   38.352693]  [] ? set_next_entity+0x9d/0xb0
[   38.352699]  [] ? tty_ldisc_deref+0x9/0x10
[   38.352703]  [] ? pick_next_task_fair+0x63/0x140
[   38.352708]  [] sys_sendmsg+0x44/0x80
[   38.352713]  [] system_call_fastpath+0x16/0x1b

It stems from holding a spinlock (trace_state_lock) while attempting to register
or unregister tracepoint hooks, making in_atomic() true in this context, leading
to the warning when the tracepoint calls might_sleep() while its taking a mutex.
Since we only use the trace_state_lock to prevent trace protocol state races, as
well as hardware stat list updates on an rcu write side, we can just convert the
spinlock to a mutex to avoid this problem.

Signed-off-by: Neil Horman 
Reported-by: Eric Dumazet 
CC: David Miller 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

rds: set correct msg_namelen

2012-10-02T16:47:41+00:00

commit 06b6a1cf6e776426766298d055bb3991957d90a7 upstream.

Jay Fenlason (fenlason@redhat.com) found a bug,
that recvfrom() on an RDS socket can return the contents of random kernel
memory to userspace if it was called with a address length larger than
sizeof(struct sockaddr_in).
rds_recvmsg() also fails to set the addr_len paramater properly before
returning, but that's just a bug.
There are also a number of cases wher recvfrom() can return an entirely bogus
address. Anything in rds_recvmsg() that returns a non-negative value but does
not go through the "sin = (struct sockaddr_in *)msg->msg_name;" code path
at the end of the while(1) loop will return up to 128 bytes of kernel memory
to userspace.

And I write two test programs to reproduce this bug, you will see that in
rds_server, fromAddr will be overwritten and the following sock_fd will be
destroyed.
Yes, it is the programmer's fault to set msg_namelen incorrectly, but it is
better to make the kernel copy the real length of address to user space in
such case.

How to run the test programs ?
I test them on 32bit x86 system, 3.5.0-rc7.

1 compile
gcc -o rds_client rds_client.c
gcc -o rds_server rds_server.c

2 run ./rds_server on one console

3 run ./rds_client on another console

4 you will see something like:
server is waiting to receive data...
old socket fd=3
server received data from client:data from client
msg.msg_namelen=32
new socket fd=-1067277685
sendmsg()
: Bad file descriptor

/***************** rds_client.c ********************/

int main(void)
{
	int sock_fd;
	struct sockaddr_in serverAddr;
	struct sockaddr_in toAddr;
	char recvBuffer[128] = "data from client";
	struct msghdr msg;
	struct iovec iov;

	sock_fd = socket(AF_RDS, SOCK_SEQPACKET, 0);
	if (sock_fd < 0) {
		perror("create socket error\n");
		exit(1);
	}

	memset(&serverAddr, 0, sizeof(serverAddr));
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	serverAddr.sin_port = htons(4001);

	if (bind(sock_fd, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) < 0) {
		perror("bind() error\n");
		close(sock_fd);
		exit(1);
	}

	memset(&toAddr, 0, sizeof(toAddr));
	toAddr.sin_family = AF_INET;
	toAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	toAddr.sin_port = htons(4000);
	msg.msg_name = &toAddr;
	msg.msg_namelen = sizeof(toAddr);
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_iov->iov_base = recvBuffer;
	msg.msg_iov->iov_len = strlen(recvBuffer) + 1;
	msg.msg_control = 0;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;

	if (sendmsg(sock_fd, &msg, 0) == -1) {
		perror("sendto() error\n");
		close(sock_fd);
		exit(1);
	}

	printf("client send data:%s\n", recvBuffer);

	memset(recvBuffer, '\0', 128);

	msg.msg_name = &toAddr;
	msg.msg_namelen = sizeof(toAddr);
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_iov->iov_base = recvBuffer;
	msg.msg_iov->iov_len = 128;
	msg.msg_control = 0;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;
	if (recvmsg(sock_fd, &msg, 0) == -1) {
		perror("recvmsg() error\n");
		close(sock_fd);
		exit(1);
	}

	printf("receive data from server:%s\n", recvBuffer);

	close(sock_fd);

	return 0;
}

/***************** rds_server.c ********************/

int main(void)
{
	struct sockaddr_in fromAddr;
	int sock_fd;
	struct sockaddr_in serverAddr;
	unsigned int addrLen;
	char recvBuffer[128];
	struct msghdr msg;
	struct iovec iov;

	sock_fd = socket(AF_RDS, SOCK_SEQPACKET, 0);
	if(sock_fd < 0) {
		perror("create socket error\n");
		exit(0);
	}

	memset(&serverAddr, 0, sizeof(serverAddr));
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	serverAddr.sin_port = htons(4000);
	if (bind(sock_fd, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) < 0) {
		perror("bind error\n");
		close(sock_fd);
		exit(1);
	}

	printf("server is waiting to receive data...\n");
	msg.msg_name = &fromAddr;

	/*
	 * I add 16 to sizeof(fromAddr), ie 32,
	 * and pay attention to the definition of fromAddr,
	 * recvmsg() will overwrite sock_fd,
	 * since kernel will copy 32 bytes to userspace.
	 *
	 * If you just use sizeof(fromAddr), it works fine.
	 * */
	msg.msg_namelen = sizeof(fromAddr) + 16;
	/* msg.msg_namelen = sizeof(fromAddr); */
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_iov->iov_base = recvBuffer;
	msg.msg_iov->iov_len = 128;
	msg.msg_control = 0;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;

	while (1) {
		printf("old socket fd=%d\n", sock_fd);
		if (recvmsg(sock_fd, &msg, 0) == -1) {
			perror("recvmsg() error\n");
			close(sock_fd);
			exit(1);
		}
		printf("server received data from client:%s\n", recvBuffer);
		printf("msg.msg_namelen=%d\n", msg.msg_namelen);
		printf("new socket fd=%d\n", sock_fd);
		strcat(recvBuffer, "--data from server");
		if (sendmsg(sock_fd, &msg, 0) == -1) {
			perror("sendmsg()\n");
			close(sock_fd);
			exit(1);
		}
	}

	close(sock_fd);
	return 0;
}

Signed-off-by: Weiping Pan 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: Statically initialize init_net.dev_base_head

2012-10-02T16:47:41+00:00

commit 734b65417b24d6eea3e3d7457e1f11493890ee1d upstream.

This change eliminates an initialization-order hazard most
recently seen when netprio_cgroup is built into the kernel.

With thanks to Eric Dumazet for catching a bug.

Signed-off-by: Mark Rustad 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

cfg80211: fix possible circular lock on reg_regdb_search()

2012-10-02T16:47:37+00:00

commit a85d0d7f3460b1a123b78e7f7e39bf72c37dfb78 upstream.

When call_crda() is called we kick off a witch hunt search
for the same regulatory domain on our internal regulatory
database and that work gets kicked off on a workqueue, this
is done while the cfg80211_mutex is held. If that workqueue
kicks off it will first lock reg_regdb_search_mutex and
later cfg80211_mutex but to ensure two CPUs will not contend
against cfg80211_mutex the right thing to do is to have the
reg_regdb_search() wait until the cfg80211_mutex is let go.

The lockdep report is pasted below.

cfg80211: Calling CRDA to update world regulatory domain

======================================================
[ INFO: possible circular locking dependency detected ]
3.3.8 #3 Tainted: G           O
-------------------------------------------------------
kworker/0:1/235 is trying to acquire lock:
 (cfg80211_mutex){+.+...}, at: [<816468a4>] set_regdom+0x78c/0x808 [cfg80211]

but task is already holding lock:
 (reg_regdb_search_mutex){+.+...}, at: [<81646828>] set_regdom+0x710/0x808 [cfg80211]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (reg_regdb_search_mutex){+.+...}:
       [<800a8384>] lock_acquire+0x60/0x88
       [<802950a8>] mutex_lock_nested+0x54/0x31c
       [<81645778>] is_world_regdom+0x9f8/0xc74 [cfg80211]

-> #1 (reg_mutex#2){+.+...}:
       [<800a8384>] lock_acquire+0x60/0x88
       [<802950a8>] mutex_lock_nested+0x54/0x31c
       [<8164539c>] is_world_regdom+0x61c/0xc74 [cfg80211]

-> #0 (cfg80211_mutex){+.+...}:
       [<800a77b8>] __lock_acquire+0x10d4/0x17bc
       [<800a8384>] lock_acquire+0x60/0x88
       [<802950a8>] mutex_lock_nested+0x54/0x31c
       [<816468a4>] set_regdom+0x78c/0x808 [cfg80211]

other info that might help us debug this:

Chain exists of:
  cfg80211_mutex --> reg_mutex#2 --> reg_regdb_search_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(reg_regdb_search_mutex);
                               lock(reg_mutex#2);
                               lock(reg_regdb_search_mutex);
  lock(cfg80211_mutex);

 *** DEADLOCK ***

3 locks held by kworker/0:1/235:
 #0:  (events){.+.+..}, at: [<80089a00>] process_one_work+0x230/0x460
 #1:  (reg_regdb_work){+.+...}, at: [<80089a00>] process_one_work+0x230/0x460
 #2:  (reg_regdb_search_mutex){+.+...}, at: [<81646828>] set_regdom+0x710/0x808 [cfg80211]

stack backtrace:
Call Trace:
[<80290fd4>] dump_stack+0x8/0x34
[<80291bc4>] print_circular_bug+0x2ac/0x2d8
[<800a77b8>] __lock_acquire+0x10d4/0x17bc
[<800a8384>] lock_acquire+0x60/0x88
[<802950a8>] mutex_lock_nested+0x54/0x31c
[<816468a4>] set_regdom+0x78c/0x808 [cfg80211]

Reported-by: Felix Fietkau 
Tested-by: Felix Fietkau 
Signed-off-by: Luis R. Rodriguez 
Reviewed-by: Johannes Berg 
Signed-off-by: John W. Linville 
Signed-off-by: Greg Kroah-Hartman

net: ipv4: ipmr_expire_timer causes crash when removing net namespace

2012-10-02T16:47:22+00:00

[ Upstream commit acbb219d5f53821b2d0080d047800410c0420ea1 ]

When tearing down a net namespace, ipv4 mr_table structures are freed
without first deactivating their timers. This can result in a crash in
run_timer_softirq.
This patch mimics the corresponding behaviour in ipv6.
Locking and synchronization seem to be adequate.
We are about to kfree mrt, so existing code should already make sure that
no other references to mrt are pending or can be created by incoming traffic.
The functions invoked here do not cause new references to mrt or other
race conditions to be created.
Invoking del_timer_sync guarantees that ipmr_expire_timer is inactive.
Both ipmr_expire_process (whose completion we may have to wait in
del_timer_sync) and mroute_clean_tables internally use mfc_unres_lock
or other synchronizations when needed, and they both only modify mrt.

Tested in Linux 3.4.8.

Signed-off-by: Francesco Ruggeri 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

l2tp: avoid to use synchronize_rcu in tunnel free function

2012-10-02T16:47:22+00:00

[ Upstream commit 99469c32f79a32d8481f87be0d3c66dad286f4ec ]

Avoid to use synchronize_rcu in l2tp_tunnel_free because context may be
atomic.

Signed-off-by: Dmitry Kozlov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

netlink: fix possible spoofing from non-root processes

2012-10-02T16:47:22+00:00

[ Upstream commit 20e1db19db5d6b9e4e83021595eab0dc8f107bef ]

Non-root user-space processes can send Netlink messages to other
processes that are well-known for being subscribed to Netlink
asynchronous notifications. This allows ilegitimate non-root
process to send forged messages to Netlink subscribers.

The userspace process usually verifies the legitimate origin in
two ways:

a) Socket credentials. If UID != 0, then the message comes from
   some ilegitimate process and the message needs to be dropped.

b) Netlink portID. In general, portID == 0 means that the origin
   of the messages comes from the kernel. Thus, discarding any
   message not coming from the kernel.

However, ctnetlink sets the portID in event messages that has
been triggered by some user-space process, eg. conntrack utility.
So other processes subscribed to ctnetlink events, eg. conntrackd,
know that the event was triggered by some user-space action.

Neither of the two ways to discard ilegitimate messages coming
from non-root processes can help for ctnetlink.

This patch adds capability validation in case that dst_pid is set
in netlink_sendmsg(). This approach is aggressive since existing
applications using any Netlink bus to deliver messages between
two user-space processes will break. Note that the exception is
NETLINK_USERSOCK, since it is reserved for netlink-to-netlink
userspace communication.

Still, if anyone wants that his Netlink bus allows netlink-to-netlink
userspace, then they can set NL_NONROOT_SEND. However, by default,
I don't think it makes sense to allow to use NETLINK_ROUTE to
communicate two processes that are sending no matter what information
that is not related to link/neighbouring/routing. They should be using
NETLINK_USERSOCK instead for that.

Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman