[ Upstream commit e03781879a0d524ce3126678d50a80484a513c4b ]
The "NET_DM" generic netlink family notifies drop locations over the
"events" multicast group. This is problematic since by default generic
netlink allows non-root users to listen to these notifications.
Fix by adding a new field to the generic netlink multicast group
structure that when set prevents non-root users or root without the
'CAP_SYS_ADMIN' capability (in the user namespace owning the network
namespace) from joining the group. Set this field for the "events"
group. Use 'CAP_SYS_ADMIN' rather than 'CAP_NET_ADMIN' because of the
nature of the information that is shared over this group.
Note that the capability check in this case will always be performed
against the initial user namespace since the family is not netns aware
and only operates in the initial network namespace.
A new field is added to the structure rather than using the "flags"
field because the existing field uses uAPI flags and it is inappropriate
to add a new uAPI flag for an internal kernel check. In net-next we can
rework the "flags" field to use internal flags and fold the new field
into it. But for now, in order to reduce the amount of changes, add a
new field.
Since the information can only be consumed by root, mark the control
plane operations that start and stop the tracing as root-only using the
'GENL_ADMIN_PERM' flag.
Tested using [1].
Before:
# capsh -- -c ./dm_repo
# capsh --drop=cap_sys_admin -- -c ./dm_repo
After:
# capsh -- -c ./dm_repo
# capsh --drop=cap_sys_admin -- -c ./dm_repo
Failed to join "events" multicast group
[1]
$ cat dm.c
#include <stdio.h>
#include <netlink/genl/ctrl.h>
#include <netlink/genl/genl.h>
#include <netlink/socket.h>
int main(int argc, char **argv)
{
struct nl_sock *sk;
int grp, err;
sk = nl_socket_alloc();
if (!sk) {
fprintf(stderr, "Failed to allocate socket\n");
return -1;
}
err = genl_connect(sk);
if (err) {
fprintf(stderr, "Failed to connect socket\n");
return err;
}
grp = genl_ctrl_resolve_grp(sk, "NET_DM", "events");
if (grp < 0) {
fprintf(stderr,
"Failed to resolve \"events\" multicast group\n");
return grp;
}
err = nl_socket_add_memberships(sk, grp, NFNLGRP_NONE);
if (err) {
fprintf(stderr, "Failed to join \"events\" multicast group\n");
return err;
}
return 0;
}
$ gcc -I/usr/include/libnl3 -lnl-3 -lnl-genl-3 -o dm_repo dm.c
Fixes: 9a8afc8d3962 ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol")
Reported-by: "The UK's National Cyber Security Centre (NCSC)" <security@ncsc.gov.uk>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231206213102.1824398-3-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 58d3aade20cdddbac6c9707ac0f3f5f8c1278b74 ]
After the blamed commit below, if the user-space application performs
window clamping when tp->rcv_wnd is 0, the TCP socket will never be
able to announce a non 0 receive window, even after completely emptying
the receive buffer and re-setting the window clamp to higher values.
Refactor tcp_set_window_clamp() to address the issue: when the user
decreases the current clamp value, set rcv_ssthresh according to the
same logic used at buffer initialization, but ensuring reserved mem
provisioning.
To avoid code duplication factor-out the relevant bits from
tcp_adjust_rcv_ssthresh() in a new helper and reuse it in the above
scenario.
When increasing the clamp value, give the rcv_ssthresh a chance to grow
according to previously implemented heuristic.
Fixes: 3aa7857fe1d7 ("tcp: enable mid stream window clamp")
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Reported-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/705dad54e6e6e9a010e571bf58e0b35a8ae70503.1701706073.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8866730aed5100f06d3d965c22f1c61f74942541 ]
AF_UNIX stream sockets are a paired socket. So sending on one of the pairs
will lookup the paired socket as part of the send operation. It is possible
however to put just one of the pairs in a BPF map. This currently increments
the refcnt on the sock in the sockmap to ensure it is not free'd by the
stack before sockmap cleans up its state and stops any skbs being sent/recv'd
to that socket.
But we missed a case. If the peer socket is closed it will be free'd by the
stack. However, the paired socket can still be referenced from BPF sockmap
side because we hold a reference there. Then if we are sending traffic through
BPF sockmap to that socket it will try to dereference the free'd pair in its
send logic creating a use after free. And following splat:
[59.900375] BUG: KASAN: slab-use-after-free in sk_wake_async+0x31/0x1b0
[59.901211] Read of size 8 at addr ffff88811acbf060 by task kworker/1:2/954
[...]
[59.905468] Call Trace:
[59.905787] <TASK>
[59.906066] dump_stack_lvl+0x130/0x1d0
[59.908877] print_report+0x16f/0x740
[59.910629] kasan_report+0x118/0x160
[59.912576] sk_wake_async+0x31/0x1b0
[59.913554] sock_def_readable+0x156/0x2a0
[59.914060] unix_stream_sendmsg+0x3f9/0x12a0
[59.916398] sock_sendmsg+0x20e/0x250
[59.916854] skb_send_sock+0x236/0xac0
[59.920527] sk_psock_backlog+0x287/0xaa0
To fix let BPF sockmap hold a refcnt on both the socket in the sockmap and its
paired socket. It wasn't obvious how to contain the fix to bpf_unix logic. The
primarily problem with keeping this logic in bpf_unix was: In the sock close()
we could handle the deref by having a close handler. But, when we are destroying
the psock through a map delete operation we wouldn't have gotten any signal
thorugh the proto struct other than it being replaced. If we do the deref from
the proto replace its too early because we need to deref the sk_pair after the
backlog worker has been stopped.
Given all this it seems best to just cache it at the end of the psock and eat 8B
for the af_unix and vsock users. Notice dgram sockets are OK because they handle
locking already.
Fixes: 94531cfcbe79 ("af_unix: Add unix_stream_proto for sockmap")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20231129012557.95371-2-john.fastabend@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 45b3fae4675dc1d4ee2d7aefa19d85ee4f891377 ]
Previously, one-element and zero-length arrays were treated as true
flexible arrays, even though they are actually "fake" flex arrays.
The __randomize_layout would leave them untouched at the end of the
struct, similarly to proper C99 flex-array members.
However, this approach changed with commit 1ee60356c2dc ("gcc-plugins:
randstruct: Only warn about true flexible arrays"). Now, only C99
flexible-array members will remain untouched at the end of the struct,
while one-element and zero-length arrays will be subject to randomization.
Fix a `__randomize_layout` crash in `struct neighbour` by transforming
zero-length array `primary_key` into a proper C99 flexible-array member.
Fixes: 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays")
Closes: https://lore.kernel.org/linux-hardening/20231124102458.GB1503258@e124191.cambridge.arm.com/
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/ZWJoRsJGnCPdJ3+2@work
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7cd5af0e937a197295f3aa3721031f0fbae49cff ]
There is no hardware supporting ct helper offload. However, prior to this
patch, a flower filter with a helper in the ct action can be successfully
set into the HW, for example (eth1 is a bnxt NIC):
# tc qdisc add dev eth1 ingress_block 22 ingress
# tc filter add block 22 proto ip flower skip_sw ip_proto tcp \
dst_port 21 ct_state -trk action ct helper ipv4-tcp-ftp
# tc filter show dev eth1 ingress
filter block 22 protocol ip pref 49152 flower chain 0 handle 0x1
eth_type ipv4
ip_proto tcp
dst_port 21
ct_state -trk
skip_sw
in_hw in_hw_count 1 <----
action order 1: ct zone 0 helper ipv4-tcp-ftp pipe
index 2 ref 1 bind 1
used_hw_stats delayed
This might cause the flower filter not to work as expected in the HW.
This patch avoids this problem by simply returning -EOPNOTSUPP in
tcf_ct_offload_act_setup() to not allow to offload flows with a helper
in act_ct.
Fixes: a21b06e73191 ("net: sched: add helper support in act_ct")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/f8685ec7702c4a448a1371a8b34b43217b583b9d.1699898008.git.lucien.xin@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c301f0981fdd3fd1ffac6836b423c4d7a8e0eb63 ]
The problem is in nft_byteorder_eval() where we are iterating through a
loop and writing to dst[0], dst[1], dst[2] and so on... On each
iteration we are writing 8 bytes. But dst[] is an array of u32 so each
element only has space for 4 bytes. That means that every iteration
overwrites part of the previous element.
I spotted this bug while reviewing commit caf3ef7468f7 ("netfilter:
nf_tables: prevent OOB access in nft_byteorder_eval") which is a related
issue. I think that the reason we have not detected this bug in testing
is that most of time we only write one element.
Fixes: ce1e7989d989 ("netfilter: nft_byteorder: provide 64bit le/be conversion")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit eb44ad4e635132754bfbcb18103f1dcb7058aedd ] This field can be read or written without socket lock being held. Add annotations to avoid load-store tearing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 0bb4d124d34044179b42a769a0c76f389ae973b6 ] This field can be read or written without socket lock being held. Add annotations to avoid load-store tearing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9bc64bd0cd765f696fcd40fc98909b1f7c73b2ba ]
Referenced commit doesn't always set iifidx when offloading the flow to
hardware. Fix the following cases:
- nf_conn_act_ct_ext_fill() is called before extension is created with
nf_conn_act_ct_ext_add() in tcf_ct_act(). This can cause rule offload with
unspecified iifidx when connection is offloaded after only single
original-direction packet has been processed by tc data path. Always fill
the new nf_conn_act_ct_ext instance after creating it in
nf_conn_act_ct_ext_add().
- Offloading of unidirectional UDP NEW connections is now supported, but ct
flow iifidx field is not updated when connection is promoted to
bidirectional which can result reply-direction iifidx to be zero when
refreshing the connection. Fill in the extension and update flow iifidx
before calling flow_offload_refresh().
Fixes: 9795ded7f924 ("net/sched: act_ct: Fill offloading tuple iifidx")
Reviewed-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Fixes: 6a9bad0069cf ("net/sched: act_ct: offload UDP NEW connections")
Link: https://lore.kernel.org/r/20231103151410.764271-1-vladbu@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1726483b79a72e0150734d5367e4a0238bf8fcff ]
I am looking at syzbot reports triggering kernel stack overflows
involving a cascade of ipvlan devices.
We can save 8 bytes in struct flowi_common.
This patch alone will not fix the issue, but is a start.
Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: wenxu <wenxu@ucloud.cn>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20231025141037.3448203-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>