linux-stable.git/net/core/sock_map.c, branch v5.6

bpf, sockmap: Remove bucket->lock from sock_{hash|map}_free

2020-03-11T13:08:52+00:00

The bucket->lock is not needed in the sock_hash_free and sock_map_free
calls, in fact it is causing a splat due to being inside rcu block.

| BUG: sleeping function called from invalid context at net/core/sock.c:2935
| in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 62, name: kworker/0:1
| 3 locks held by kworker/0:1/62:
|  #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #2: ffff8881381f6df8 (&stab->lock){+...}, at: sock_map_free+0x26/0x180
| CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04008-g7b083332376e #454
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: events bpf_map_free_deferred
| Call Trace:
|  dump_stack+0x71/0xa0
|  ___might_sleep.cold+0xa6/0xb6
|  lock_sock_nested+0x28/0x90
|  sock_map_free+0x5f/0x180
|  bpf_map_free_deferred+0x58/0x80
|  process_one_work+0x260/0x5e0
|  worker_thread+0x4d/0x3e0
|  kthread+0x108/0x140
|  ? process_one_work+0x5e0/0x5e0
|  ? kthread_park+0x90/0x90
|  ret_from_fork+0x3a/0x50

The reason we have stab->lock and bucket->locks in sockmap code is to
handle checking EEXIST in update/delete cases. We need to be careful during
an update operation that we check for EEXIST and we need to ensure that the
psock object is not in some partial state of removal/insertion while we do
this. So both map_update_common and sock_map_delete need to guard from being
run together potentially deleting an entry we are checking, etc. But by the
time we get to the tear-down code in sock_{ma[|hash}_free we have already
disconnected the map and we just did synchronize_rcu() in the line above so
no updates/deletes should be in flight. Because of this we can drop the
bucket locks from the map free'ing code, noting no update/deletes can be
in-flight.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Reported-by: Jakub Sitnicki 
Suggested-by: Jakub Sitnicki 
Signed-off-by: John Fastabend 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/158385850787.30597.8346421465837046618.stgit@john-Precision-5820-Tower

bpf, sockhash: Synchronize_rcu before free'ing map

2020-02-07T21:36:26+00:00

We need to have a synchronize_rcu before free'ing the sockhash because any
outstanding psock references will have a pointer to the map and when they
use it, this could trigger a use after free.

This is a sister fix for sockhash, following commit 2bb90e5cc90e ("bpf:
sockmap, synchronize_rcu before free'ing map") which addressed sockmap,
which comes from a manual audit.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20200206111652.694507-3-jakub@cloudflare.com

bpf, sockmap: Don't sleep while holding RCU lock on tear-down

2020-02-07T21:36:26+00:00

rcu_read_lock is needed to protect access to psock inside sock_map_unref
when tearing down the map. However, we can't afford to sleep in lock_sock
while in RCU read-side critical section. Grab the RCU lock only after we
have locked the socket.

This fixes RCU warnings triggerable on a VM with 1 vCPU when free'ing a
sockmap/sockhash that contains at least one socket:

| =============================
| WARNING: suspicious RCU usage
| 5.5.0-04005-g8fc91b972b73 #450 Not tainted
| -----------------------------
| include/linux/rcupdate.h:272 Illegal context switch in RCU read-side critical section!
|
| other info that might help us debug this:
|
|
| rcu_scheduler_active = 2, debug_locks = 1
| 4 locks held by kworker/0:1/62:
|  #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #2: ffffffff82065d20 (rcu_read_lock){....}, at: sock_map_free+0x5/0x170
|  #3: ffff8881368c5df8 (&stab->lock){+...}, at: sock_map_free+0x64/0x170
|
| stack backtrace:
| CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04005-g8fc91b972b73 #450
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: events bpf_map_free_deferred
| Call Trace:
|  dump_stack+0x71/0xa0
|  ___might_sleep+0x105/0x190
|  lock_sock_nested+0x28/0x90
|  sock_map_free+0x95/0x170
|  bpf_map_free_deferred+0x58/0x80
|  process_one_work+0x260/0x5e0
|  worker_thread+0x4d/0x3e0
|  kthread+0x108/0x140
|  ? process_one_work+0x5e0/0x5e0
|  ? kthread_park+0x90/0x90
|  ret_from_fork+0x3a/0x50

| =============================
| WARNING: suspicious RCU usage
| 5.5.0-04005-g8fc91b972b73-dirty #452 Not tainted
| -----------------------------
| include/linux/rcupdate.h:272 Illegal context switch in RCU read-side critical section!
|
| other info that might help us debug this:
|
|
| rcu_scheduler_active = 2, debug_locks = 1
| 4 locks held by kworker/0:1/62:
|  #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0
|  #2: ffffffff82065d20 (rcu_read_lock){....}, at: sock_hash_free+0x5/0x1d0
|  #3: ffff888139966e00 (&htab->buckets[i].lock){+...}, at: sock_hash_free+0x92/0x1d0
|
| stack backtrace:
| CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04005-g8fc91b972b73-dirty #452
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: events bpf_map_free_deferred
| Call Trace:
|  dump_stack+0x71/0xa0
|  ___might_sleep+0x105/0x190
|  lock_sock_nested+0x28/0x90
|  sock_hash_free+0xec/0x1d0
|  bpf_map_free_deferred+0x58/0x80
|  process_one_work+0x260/0x5e0
|  worker_thread+0x4d/0x3e0
|  kthread+0x108/0x140
|  ? process_one_work+0x5e0/0x5e0
|  ? kthread_park+0x90/0x90
|  ret_from_fork+0x3a/0x50

Fixes: 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during tear down")
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20200206111652.694507-2-jakub@cloudflare.com

bpf, sockmap: Check update requirements after locking

2020-02-07T21:28:04+00:00

It's currently possible to insert sockets in unexpected states into
a sockmap, due to a TOCTTOU when updating the map from a syscall.
sock_map_update_elem checks that sk->sk_state == TCP_ESTABLISHED,
locks the socket and then calls sock_map_update_common. At this
point, the socket may have transitioned into another state, and
the earlier assumptions don't hold anymore. Crucially, it's
conceivable (though very unlikely) that a socket has become unhashed.
This breaks the sockmap's assumption that it will get a callback
via sk->sk_prot->unhash.

Fix this by checking the (fixed) sk_type and sk_protocol without the
lock, followed by a locked check of sk_state.

Unfortunately it's not possible to push the check down into
sock_(map|hash)_update_common, since BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB
run before the socket has transitioned from TCP_SYN_RECV into
TCP_ESTABLISHED.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Lorenz Bauer 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jakub Sitnicki 
Link: https://lore.kernel.org/bpf/20200207103713.28175-1-lmb@cloudflare.com

bpf: Sockmap, ensure sock lock held during tear down

2020-01-15T22:26:13+00:00

The sock_map_free() and sock_hash_free() paths used to delete sockmap
and sockhash maps walk the maps and destroy psock and bpf state associated
with the socks in the map. When done the socks no longer have BPF programs
attached and will function normally. This can happen while the socks in
the map are still "live" meaning data may be sent/received during the walk.

Currently, though we don't take the sock_lock when the psock and bpf state
is removed through this path. Specifically, this means we can be writing
into the ops structure pointers such as sendmsg, sendpage, recvmsg, etc.
while they are also being called from the networking side. This is not
safe, we never used proper READ_ONCE/WRITE_ONCE semantics here if we
believed it was safe. Further its not clear to me its even a good idea
to try and do this on "live" sockets while networking side might also
be using the socket. Instead of trying to reason about using the socks
from both sides lets realize that every use case I'm aware of rarely
deletes maps, in fact kubernetes/Cilium case builds map at init and
never tears it down except on errors. So lets do the simple fix and
grab sock lock.

This patch wraps sock deletes from maps in sock lock and adds some
annotations so we catch any other cases easier.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend 
Signed-off-by: Daniel Borkmann 
Acked-by: Song Liu 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-3-john.fastabend@gmail.com

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2019-09-15T12:17:27+00:00

Minor overlapping changes in the btusb and ixgbe drivers.

Signed-off-by: David S. Miller

net: sock_map, fix missing ulp check in sock hash case

2019-09-05T09:56:19+00:00

sock_map and ULP only work together when ULP is loaded after the sock
map is loaded. In the sock_map case we added a check for this to fail
the load if ULP is already set. However, we missed the check on the
sock_hash side.

Add a ULP check to the sock_hash update path.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Reported-by: syzbot+7a6ee4d0078eac6bf782@syzkaller.appspotmail.com
Signed-off-by: John Fastabend 
Signed-off-by: David S. Miller

net/tls: use RCU protection on icsk->icsk_ulp_data

2019-09-01T06:44:28+00:00

We need to make sure context does not get freed while diag
code is interrogating it. Free struct tls_context with
kfree_rcu().

We add the __rcu annotation directly in icsk, and cast it
away in the datapath accessor. Presumably all ULPs will
do a similar thing.

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller

bpf: sockmap, only create entry if ulp is not already enabled

2019-07-22T14:04:17+00:00

Sockmap does not currently support adding sockets after TLS has been
enabled. There never was a real use case for this so it was never
added. But, we lost the test for ULP at some point so add it here
and fail the socket insert if TLS is enabled. Future work could
make sockmap support this use case but fixup the bug here.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend 
Signed-off-by: Daniel Borkmann

bpf: sockmap, synchronize_rcu before free'ing map

2019-07-22T14:04:17+00:00

We need to have a synchronize_rcu before free'ing the sockmap because
any outstanding psock references will have a pointer to the map and
when they use this could trigger a use after free.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend 
Signed-off-by: Daniel Borkmann