netlink_recvmsg() does not need to change transport header.
If transport header was needed, it should have been reset
by the producer (netlink_dump()), not the consumer(s).
The following trace probably happened when multiple threads
were using MSG_PEEK.
BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg
write to 0xffff88811e9f15b2 of 2 bytes by task 32012 on cpu 1:
skb_reset_transport_header include/linux/skbuff.h:2760 [inline]
netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978
sock_recvmsg_nosec net/socket.c:948 [inline]
sock_recvmsg net/socket.c:966 [inline]
__sys_recvfrom+0x204/0x2c0 net/socket.c:2097
__do_sys_recvfrom net/socket.c:2115 [inline]
__se_sys_recvfrom net/socket.c:2111 [inline]
__x64_sys_recvfrom+0x74/0x90 net/socket.c:2111
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
write to 0xffff88811e9f15b2 of 2 bytes by task 32005 on cpu 0:
skb_reset_transport_header include/linux/skbuff.h:2760 [inline]
netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978
____sys_recvmsg+0x162/0x2f0
___sys_recvmsg net/socket.c:2674 [inline]
__sys_recvmsg+0x209/0x3f0 net/socket.c:2704
__do_sys_recvmsg net/socket.c:2714 [inline]
__se_sys_recvmsg net/socket.c:2711 [inline]
__x64_sys_recvmsg+0x42/0x50 net/socket.c:2711
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0xffff -> 0x0000
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32005 Comm: syz-executor.4 Not tainted 5.18.0-rc1-syzkaller-00328-ge1f700ebd6be-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220505161946.2867638-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
skb_recv_datagram() has two parameters 'flags' and 'noblock' that are
merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0)'
As 'flags' may contain MSG_DONTWAIT as value most callers split the 'flags'
into 'flags' and 'noblock' with finally obsolete bit operations like this:
skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &rc);
And this is not even done consistently with the 'flags' parameter.
This patch removes the obsolete and costly splitting into two parameters
and only performs bit operations when really needed on the caller side.
One missing conversion thankfully reported by kernel test robot. I missed
to enable kunit tests to build the mctp code.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When a netlink message is received, netlink_recvmsg() fills in the address
of the sender. One of the fields is the 32-bit bitfield nl_groups, which
carries the multicast group on which the message was received. The least
significant bit corresponds to group 1, and therefore the highest group
that the field can represent is 32. Above that, the UB sanitizer flags the
out-of-bounds shift attempts.
Which bits end up being set in such case is implementation defined, but
it's either going to be a wrong non-zero value, or zero, which is at least
not misleading. Make the latter choice deterministic by always setting to 0
for higher-numbered multicast groups.
To get information about membership in groups >= 32, userspace is expected
to use nl_pktinfo control messages[0], which are enabled by NETLINK_PKTINFO
socket option.
[0] https://lwn.net/Articles/147608/
The way to trigger this issue is e.g. through monitoring the BRVLAN group:
# bridge monitor vlan &
# ip link add name br type bridge
Which produces the following citation:
UBSAN: shift-out-of-bounds in net/netlink/af_netlink.c:162:19
shift exponent 32 is too large for 32-bit type 'int'
Fixes: f7fa9b10ed ("[NETLINK]: Support dynamic number of multicast groups per netlink family")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/2bef6aabf201d1fc16cca139a744700cff9dcb04.1647527635.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sock.h is pretty heavily used (5k objects rebuilt on x86 after
it's touched). We can drop the include of filter.h from it and
add a forward declaration of struct sk_filter instead.
This decreases the number of rebuilt objects when bpf.h
is touched from ~5k to ~1k.
There's a lot of missing includes this was masking. Primarily
in networking tho, this time.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/bpf/20211229004913.513372-1-kuba@kernel.org
This is distracting really, let's make this simpler,
because many callers had to take care of this
by themselves, even if on x86 this adds more
code than really needed.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While existing code is correct, KCSAN is reporting
a data-race in netlink_insert / netlink_sendmsg [1]
It is correct to read nlk->bound without a lock, as netlink_autobind()
will acquire all needed locks.
[1]
BUG: KCSAN: data-race in netlink_insert / netlink_sendmsg
write to 0xffff8881031c8b30 of 1 bytes by task 18752 on cpu 0:
netlink_insert+0x5cc/0x7f0 net/netlink/af_netlink.c:597
netlink_autobind+0xa9/0x150 net/netlink/af_netlink.c:842
netlink_sendmsg+0x479/0x7c0 net/netlink/af_netlink.c:1892
sock_sendmsg_nosec net/socket.c:703 [inline]
sock_sendmsg net/socket.c:723 [inline]
____sys_sendmsg+0x360/0x4d0 net/socket.c:2392
___sys_sendmsg net/socket.c:2446 [inline]
__sys_sendmsg+0x1ed/0x270 net/socket.c:2475
__do_sys_sendmsg net/socket.c:2484 [inline]
__se_sys_sendmsg net/socket.c:2482 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2482
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff8881031c8b30 of 1 bytes by task 18751 on cpu 1:
netlink_sendmsg+0x270/0x7c0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:703 [inline]
sock_sendmsg net/socket.c:723 [inline]
__sys_sendto+0x2a8/0x370 net/socket.c:2019
__do_sys_sendto net/socket.c:2031 [inline]
__se_sys_sendto net/socket.c:2027 [inline]
__x64_sys_sendto+0x74/0x90 net/socket.c:2027
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x00 -> 0x01
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18751 Comm: syz-executor.0 Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Fixes: da314c9923 ("netlink: Replace rhash_portid with bound")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the case when nlh is NULL in nlmsg_report(),
so that the caller doesn't need to deal with this case.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
Yonghong Song report:
The bpf selftest tc_bpf failed with latest bpf-next.
The following is the command to run and the result:
$ ./test_progs -n 132
[ 40.947571] bpf_testmod: loading out-of-tree module taints kernel.
test_tc_bpf:PASS:test_tc_bpf__open_and_load 0 nsec
test_tc_bpf:PASS:bpf_tc_hook_create(BPF_TC_INGRESS) 0 nsec
test_tc_bpf:PASS:bpf_tc_hook_create invalid hook.attach_point 0 nsec
test_tc_bpf_basic:PASS:bpf_obj_get_info_by_fd 0 nsec
test_tc_bpf_basic:PASS:bpf_tc_attach 0 nsec
test_tc_bpf_basic:PASS:handle set 0 nsec
test_tc_bpf_basic:PASS:priority set 0 nsec
test_tc_bpf_basic:PASS:prog_id set 0 nsec
test_tc_bpf_basic:PASS:bpf_tc_attach replace mode 0 nsec
test_tc_bpf_basic:PASS:bpf_tc_query 0 nsec
test_tc_bpf_basic:PASS:handle set 0 nsec
test_tc_bpf_basic:PASS:priority set 0 nsec
test_tc_bpf_basic:PASS:prog_id set 0 nsec
libbpf: Kernel error message: Failed to send filter delete notification
test_tc_bpf_basic:FAIL:bpf_tc_detach unexpected error: -3 (errno 3)
test_tc_bpf:FAIL:test_tc_internal ingress unexpected error: -3 (errno 3)
The failure seems due to the commit
cfdf0d9ae7 ("rtnetlink: use nlmsg_notify() in rtnetlink_send()")
Deal with ESRCH error in nlmsg_notify() even the report variable is zero.
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Link: https://lore.kernel.org/r/20210719051816.11762-1-yajun.deng@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
It has 'if (err >0 )' statement in nlmsg_unicast(), so use nlmsg_unicast()
instead of netlink_unicast(), this looks more concise.
v2: remove the change in netfilter.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces a function wrapper to call the sk_error_report
callback. That will prepare to add additional handling whenever
sk_error_report is called, for example to trace socket errors.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Syzbot reports that in mac80211 we have a potential deadlock
between our "local->stop_queue_reasons_lock" (spinlock) and
netlink's nl_table_lock (rwlock). This is because there's at
least one situation in which we might try to send a netlink
message with this spinlock held while it is also possible to
take the spinlock from a hardirq context, resulting in the
following deadlock scenario reported by lockdep:
CPU0 CPU1
---- ----
lock(nl_table_lock);
local_irq_disable();
lock(&local->queue_stop_reason_lock);
lock(nl_table_lock);
<Interrupt>
lock(&local->queue_stop_reason_lock);
This seems valid, we can take the queue_stop_reason_lock in
any kind of context ("CPU0"), and call ieee80211_report_ack_skb()
with the spinlock held and IRQs disabled ("CPU1") in some
code path (ieee80211_do_stop() via ieee80211_free_txskb()).
Short of disallowing netlink use in scenarios like these
(which would be rather complex in mac80211's case due to
the deep callchain), it seems the only fix for this is to
disable IRQs while nl_table_lock is held to avoid hitting
this scenario, this disallows the "CPU0" portion of the
reported deadlock.
Note that the writer side (netlink_table_grab()) already
disables IRQs for this lock.
Unfortunately though, this seems like a huge hammer, and
maybe the whole netlink table locking should be reworked.
Reported-by: syzbot+69ff9dff50dcfe14ddd4@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When I added support to allow generic netlink multicast groups to be
restricted to subscribers with CAP_NET_ADMIN I was unaware that a
genl_bind implementation already existed in the past.
It was reverted due to ABBA deadlock:
1. ->netlink_bind gets called with the table lock held.
2. genetlink bind callback is invoked, it grabs the genl lock.
But when a new genl subsystem is (un)registered, these two locks are
taken in reverse order.
One solution would be to revert again and add a comment in genl
referring 1e82a62fec, "genetlink: remove genl_bind").
This would need a second change in mptcp to not expose the raw token
value anymore, e.g. by hashing the token with a secret key so userspace
can still associate subflow events with the correct mptcp connection.
However, Paolo Abeni reminded me to double-check why the netlink table is
locked in the first place.
I can't find one. netlink_bind() is already called without this lock
when userspace joins a group via NETLINK_ADD_MEMBERSHIP setsockopt.
Same holds for the netlink_unbind operation.
Digging through the history, commit f773608026
("netlink: access nlk groups safely in netlink bind and getname")
expanded the lock scope.
commit 3a20773bee ("net: netlink: cap max groups which will be considered in netlink_bind()")
... removed the nlk->ngroups access that the lock scope
extension was all about.
Reduce the lock scope again and always call ->netlink_bind without
the table lock.
The Fixes tag should be vs. the patch mentioned in the link below,
but that one got squash-merged into the patch that came earlier in the
series.
Fixes: 4d54cc3211 ("mptcp: avoid lock_fast usage in accept path")
Link: https://lore.kernel.org/mptcp/20210213000001.379332-8-mathew.j.martineau@linux.intel.com/T/#u
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Sean Tranchetti <stranche@codeaurora.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Once event support is added this may need to allocate memory while msk
lock is held with softirqs disabled.
Not using lock_fast also allows to do the allocation with GFP_KERNEL.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Often userspace won't request the extack information, or they don't log it
because of log level or so, and even when they do, sometimes it's not
enough to know exactly what caused the error.
Netlink extack is the standard way of reporting erros with descriptive
error messages. With a trace point on it, we then can know exactly where
the error happened, regardless of userspace app. Also, we can even see if
the err msg was overwritten.
The wrapper do_trace_netlink_extack() is because trace points shouldn't be
called from .h files, as trace points are not that small, and the function
call to do_trace_netlink_extack() on the macros is not protected by
tracepoint_enabled() because the macros are called from modules, and this
would require exporting some trace structs. As this is error path, it's
better to export just the wrapper instead.
v2: removed leftover tracepoint declaration
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/4546b63e67b2989789d146498b13cc09e1fdc543.1612403190.git.marcelo.leitner@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a new attribute NLMSGERR_ATTR_POLICY to the extended ACK
to advertise the policy, e.g. if an attribute was out of range,
you'll know the range that's permissible.
Add new NL_SET_ERR_MSG_ATTR_POL() and NL_SET_ERR_MSG_ATTR_POL()
macros to set this, since realistically it's only useful to do
this when the bad attribute (offset) is also returned.
Use it in lib/nlattr.c which practically does all the policy
validation.
v2:
- add and use netlink_policy_dump_attr_size_estimate()
v3:
- remove redundant break
v4:
- really remove redundant break ... sorry
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Refactor the per-attribute policy writing into a new
helper function, to be used later for dumping out the
policy of a rejected attribute.
v2:
- fix some indentation
v3:
- change variable order in netlink_policy_dump_write()
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We don't have good validation policy for existing unsigned int attrs
which serve as flags (for new ones we could use NLA_BITFIELD32).
With increased use of policy dumping having the validation be
expressed as part of the policy is important. Add validation
policy in form of a mask of supported/valid bits.
Support u64 in the uAPI to be future-proof, but really for now
the embedded mask member can only hold 32 bits, so anything with
bit 32+ set will always fail validation.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
