There is no functionality change for this patch.
Struct bpf_iter_reg is used to register a bpf_iter target,
which includes information for both prog_load, link_create
and seq_file creation.
This patch puts fields related seq_file creation into
a different structure. This will be useful for map
elements iterator where one iterator covers different
map types and different map types may have different
seq_ops, init/fini private_data function and
private_data size.
Change-Id: I2577d77f6b6be71319457720547ba77cff04c68b
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184109.590030-1-yhs@fb.com
It's mostly a copy paste of commit 6086d29def80 ("bpf: Add bpf_map iterator")
that is use to implement bpf_seq_file opreations to traverse all bpf programs.
v1->v2: Tweak to use build time btf_id
Change-Id: Id105cdc90824f19060f9e6ef51369c6290e925d5
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Currently, the pos pointer in bpf iterator map/task/task_file
seq_ops->start() is always incremented.
This is incorrect. It should be increased only if
*pos is 0 (for SEQ_START_TOKEN) since these start()
function actually returns the first real object.
If *pos is not 0, it merely found the object
based on the state in seq->private, and not really
advancing the *pos. This patch fixed this issue
by only incrementing *pos if it is 0.
Note that the old *pos calculation, although not
correct, does not affect correctness of bpf_iter
as bpf_iter seq_file->read() does not support llseek.
This patch also renamed "mid" in bpf_map iterator
seq_file private data to "map_id" for better clarity.
Fixes: 6086d29def80 ("bpf: Add bpf_map iterator")
Fixes: eaaacd23910f ("bpf: Add task and task/file iterator targets")
Change-Id: I37a742c1706f84b26153032c3e0080b85769c5e6
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722195156.4029817-1-yhs@fb.com
One additional field btf_id is added to struct
bpf_ctx_arg_aux to store the precomputed btf_ids.
The btf_id is computed at build time with
BTF_ID_LIST or BTF_ID_LIST_GLOBAL macro definitions.
All existing bpf iterators are changed to used
pre-compute btf_ids.
Change-Id: I1cb3532f3c31b426f279ed17e092e311649d54e1
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720163403.1393551-1-yhs@fb.com
The bpf iterator for udp is implemented. Both udp4 and udp6
sockets will be traversed. It is up to bpf program to
filter for udp4 or udp6 only, or both families of sockets.
Change-Id: I05176138b99a0ad5a9d3829ca0480bc0bed33cbc
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230813.3988404-1-yhs@fb.com
Similar to tcp_iter_state, a new field bpf_seq_afinfo is
added to udp_iter_state to provide bpf udp iterator
afinfo.
This does not change /proc/net/{udp, udp6} behavior. But
it enables bpf iterator to avoid get afinfo from PDE_DATA
and iterate through all udp and udp6 sockets in one pass.
Change-Id: I75e4639ec944f57ce0f05c2b4a4d728f69aa806f
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230812.3988347-1-yhs@fb.com
The bpf iterator for tcp is implemented. Both tcp4 and tcp6
sockets will be traversed. It is up to bpf program to
filter for tcp4 or tcp6 only, or both families of sockets.
Change-Id: Ibc3bd9081feb4c6b8a30dfa5002aa3c6aaa7f6ce
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230805.3987959-1-yhs@fb.com
A new field bpf_seq_afinfo is added to tcp_iter_state
to provide bpf tcp iterator afinfo. There are two
reasons on why we did this.
First, the current way to get afinfo from PDE_DATA
does not work for bpf iterator as its seq_file
inode does not conform to /proc/net/{tcp,tcp6}
inode structures. More specifically, anonymous
bpf iterator will use an anonymous inode which
is shared in the system and we cannot change inode
private data structure at all.
Second, bpf iterator for tcp/tcp6 wants to
traverse all tcp and tcp6 sockets in one pass
and bpf program can control whether they want
to skip one sk_family or not. Having a different
afinfo with family AF_UNSPEC make it easier
to understand in the code.
This patch does not change /proc/net/{tcp,tcp6} behavior
as the bpf_seq_afinfo will be NULL for these two proc files.
Change-Id: I6bc5c311247e884bf76c8d133bf9b820706a1ce0
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230804.3987829-1-yhs@fb.com
tcp and udp bpf_iter can reuse some socket ids in
btf_sock_ids, so make it global.
I put the extern definition in btf_ids.h as a central
place so it can be easily discovered by developers.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720163402.1393427-1-yhs@fb.com
Change-Id: I10a242ef01bd1f4460aee305b8d1d9620eb6edef
Currently, socket types (struct tcp_sock, udp_sock, etc.)
used by bpf_skc_to_*() helpers are computed when vmlinux_btf
is first built in the kernel.
Commit 5a2798ab32ba
("bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros")
implemented a mechanism to compute btf_ids at kernel build
time which can simplify kernel implementation and reduce
runtime overhead by removing in-kernel btf_id calculation.
This patch did exactly this, removing in-kernel btf_id
computation and utilizing build-time btf_id computation.
If CONFIG_DEBUG_INFO_BTF is not defined, BTF_ID_LIST will
define an array with size of 5, which is not enough for
btf_sock_ids. So define its own static array if
CONFIG_DEBUG_INFO_BTF is not defined.
Change-Id: I4d759318700b7a0e489dbd63296c42b584e0c1af
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720163358.1393023-1-yhs@fb.com
Add a new program type BPF_PROG_TYPE_SK_LOOKUP with a dedicated attach type
BPF_SK_LOOKUP. The new program kind is to be invoked by the transport layer
when looking up a listening socket for a new connection request for
connection oriented protocols, or when looking up an unconnected socket for
a packet for connection-less protocols.
When called, SK_LOOKUP BPF program can select a socket that will receive
the packet. This serves as a mechanism to overcome the limits of what
bind() API allows to express. Two use-cases driving this work are:
(1) steer packets destined to an IP range, on fixed port to a socket
192.0.2.0/24, port 80 -> NGINX socket
(2) steer packets destined to an IP address, on any port to a socket
198.51.100.1, any port -> L7 proxy socket
In its run-time context program receives information about the packet that
triggered the socket lookup. Namely IP version, L4 protocol identifier, and
address 4-tuple. Context can be further extended to include ingress
interface identifier.
To select a socket BPF program fetches it from a map holding socket
references, like SOCKMAP or SOCKHASH, and calls bpf_sk_assign(ctx, sk, ...)
helper to record the selection. Transport layer then uses the selected
socket as a result of socket lookup.
In its basic form, SK_LOOKUP acts as a filter and hence must return either
SK_PASS or SK_DROP. If the program returns with SK_PASS, transport should
look for a socket to receive the packet, or use the one selected by the
program if available, while SK_DROP informs the transport layer that the
lookup should fail.
This patch only enables the user to attach an SK_LOOKUP program to a
network namespace. Subsequent patches hook it up to run on local delivery
path in ipv4 and ipv6 stacks.
Suggested-by: Marek Majkowski <marek@cloudflare.com>
Change-Id: I4a245236f759b4789883365ffea7ef1e793c3ac8
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200717103536.397595-3-jakub@cloudflare.com
Extend the BPF netns link callbacks to rebuild (grow/shrink) or update the
prog_array at given position when link gets attached/updated/released.
This let's us lift the limit of having just one link attached for the new
attach type introduced by subsequent patch.
No functional changes intended.
Change-Id: I800d54d43aefc162cd4ccd12e68bbf3cf79701c2
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200717103536.397595-2-jakub@cloudflare.com
This reverts commit cedd91c6f4c46fe002ec1a33139620321a62a399.
It conflicts with the BPF merge and will have to be added back later "by
hand".
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I9b070d804c16b12a416ddc630c4440ea85f5531b
Introduce the capability to attach an eBPF program to cpumap entries.
The idea behind this feature is to add the possibility to define on
which CPU run the eBPF program if the underlying hw does not support
RSS. Current supported verdicts are XDP_DROP and XDP_PASS.
This patch has been tested on Marvell ESPRESSObin using xdp_redirect_cpu
sample available in the kernel tree to identify possible performance
regressions. Results show there are no observable differences in
packet-per-second:
$./xdp_redirect_cpu --progname xdp_cpu_map0 --dev eth0 --cpu 1
rx: 354.8 Kpps
rx: 356.0 Kpps
rx: 356.8 Kpps
rx: 356.3 Kpps
rx: 356.6 Kpps
rx: 356.6 Kpps
rx: 356.7 Kpps
rx: 355.8 Kpps
rx: 356.8 Kpps
rx: 356.8 Kpps
Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Change-Id: Ib09a822f483667441e6b287a3ac694a82e9e3e0f
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/5c9febdf903d810b3415732e5cd98491d7d9067a.1594734381.git.lorenzo@kernel.org
Move the guts of xdp_convert_buff_to_frame to a new helper,
xdp_update_frame_from_buff so it can be reused removing code duplication
Suggested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Change-Id: Iafc031ea7f715930756839d27a82160548820c09
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/90a68c283d7ebeb48924934c9b7ac79492300472.1594734381.git.lorenzo@kernel.org
The veth driver can run XDP in "native" mode in it's own NAPI
handler, and since commit 9fc8d518d9 ("veth: Handle xdp_frames in
xdp napi ring") packets can come in two forms either xdp_frame or
skb, calling respectively veth_xdp_rcv_one() or veth_xdp_rcv_skb().
For packets to arrive in xdp_frame format, they will have been
redirected from an XDP native driver. In case of XDP_PASS or no
XDP-prog attached, the veth driver will allocate and create an SKB.
The current code in veth_xdp_rcv_one() xdp_frame case, had to guess
the frame truesize of the incoming xdp_frame, when using
veth_build_skb(). With xdp_frame->frame_sz this is not longer
necessary.
Calculating the frame_sz in veth_xdp_rcv_skb() skb case, is done
similar to the XDP-generic handling code in net/core/dev.c.
Change-Id: Ie4db1e5a679972947703fe06a03ec4475687c57f
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Toshiaki Makita <toshiaki.makita1@gmail.com>
Link: https://lore.kernel.org/bpf/158945338840.97035.935897116345700902.stgit@firesoul
As it has been already done for devmap, introduce 'struct bpf_cpumap_val'
to formalize the expected values that can be passed in for a CPUMAP.
Update cpumap code to use the struct.
Change-Id: I747c5bd9ce9032f3bcbe9a87c8d03b3b803e5bc0
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/754f950674665dae6139c061d28c1d982aaf4170.1594734381.git.lorenzo@kernel.org
Add tests to verify ability to add an XDP program to a
entry in a DEVMAP.
Add negative tests to show DEVMAP programs can not be
attached to devices as a normal XDP program, and accesses
to egress_ifindex require BPF_XDP_DEVMAP attach type.
Change-Id: Ic91c2835212b87d397dc33161c718619f26a8ac7
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200529220716.75383-6-dsahern@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 77361825bb ("bpf: cpumap use ptr_ring_consume_batched") changed
away from using single frame ptr_ring dequeue (__ptr_ring_consume) to
consume a batched, but it uses a locked version, which as the comment
explain isn't needed.
Change to use the non-locked version __ptr_ring_consume_batched.
Fixes: 77361825bb ("bpf: cpumap use ptr_ring_consume_batched")
Change-Id: I0a0f25075dfb5e72d5d644b44c007b65499b1f57
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/a9c7d06f9a009e282209f0c8c7b2c5d9b9ad60b9.1594734381.git.lorenzo@kernel.org
This way the ID is resolved during compile time,
and we can remove the runtime name search.
Change-Id: I473cfe49f663c28f852ee113332ead58b044d7de
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-7-jolsa@kernel.org
Now when we moved the helpers btf_id arrays into .BTF_ids section,
we can remove the code that resolve those IDs in runtime.
Change-Id: I50970ca8de716592eefdd927842e209bd8efd9ca
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-6-jolsa@kernel.org
Using BTF_ID_LIST macro to define lists for several helpers
using BTF arguments.
And running resolve_btfids on vmlinux elf object during linking,
so the .BTF_ids section gets the IDs resolved.
Change-Id: I7299a611fb88195d58b2899e37d2ef5ded84e158
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-5-jolsa@kernel.org
Adding support to generate .BTF_ids section that will hold BTF
ID lists for verifier.
Adding macros that will help to define lists of BTF ID values
placed in .BTF_ids section. They are initially filled with zeros
(during compilation) and resolved later during the linking phase
by resolve_btfids tool.
Following defines list of one BTF ID value:
BTF_ID_LIST(bpf_skb_output_btf_ids)
BTF_ID(struct, sk_buff)
It also defines following variable to access the list:
extern u32 bpf_skb_output_btf_ids[];
The BTF_ID_UNUSED macro defines 4 zero bytes. It's used when we
want to define 'unused' entry in BTF_ID_LIST, like:
BTF_ID_LIST(bpf_skb_output_btf_ids)
BTF_ID(struct, sk_buff)
BTF_ID_UNUSED
BTF_ID(struct, task_struct)
Suggested-by: Andrii Nakryiko <andriin@fb.com>
Change-Id: Ia4b1d2daf80d3c9ff35b51edb6ce95b5fe2b4bc7
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-4-jolsa@kernel.org
bpf_sk_reuseport_detach is currently called when sk->sk_user_data
is not NULL. It is incorrect because sk->sk_user_data may not be
managed by the bpf's reuseport_array. It has been reported in [1] that,
the bpf_sk_reuseport_detach() which is called from udp_lib_unhash() has
corrupted the sk_user_data managed by l2tp.
This patch solves it by using another bit (defined as SK_USER_DATA_BPF)
of the sk_user_data pointer value. It marks that a sk_user_data is
managed/owned by BPF.
The patch depends on a PTRMASK introduced in
commit f1ff5ce2cd5e ("net, sk_msg: Clear sk_user_data pointer on clone if tagged").
[ Note: sk->sk_user_data is used by bpf's reuseport_array only when a sk is
added to the bpf's reuseport_array.
i.e. doing setsockopt(SO_REUSEPORT) and having "sk->sk_reuseport == 1"
alone will not stop sk->sk_user_data being used by other means. ]
[1]: https://lore.kernel.org/netdev/20200706121259.GA20199@katalix.com/
Fixes: 5dc4c4b7d4 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY")
Reported-by: James Chapman <jchapman@katalix.com>
Reported-by: syzbot+9f092552ba9a5efca5df@syzkaller.appspotmail.com
Change-Id: I4f075d4ad5e233ab785e45c1ad9f34a6036ff1ba
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: James Chapman <jchapman@katalix.com>
Acked-by: James Chapman <jchapman@katalix.com>
Link: https://lore.kernel.org/bpf/20200709061110.4019316-1-kafai@fb.com
sk_user_data can hold a pointer to an object that is not intended to be
shared between the parent socket and the child that gets a pointer copy on
clone. This is the case when sk_user_data points at reference-counted
object, like struct sk_psock.
One way to resolve it is to tag the pointer with a no-copy flag by
repurposing its lowest bit. Based on the bit-flag value we clear the child
sk_user_data pointer after cloning the parent socket.
The no-copy flag is stored in the pointer itself as opposed to externally,
say in socket flags, to guarantee that the pointer and the flag are copied
from parent to child socket in an atomic fashion. Parent socket state is
subject to change while copying, we don't hold any locks at that time.
This approach relies on an assumption that sk_user_data holds a pointer to
an object aligned at least 2 bytes. A manual audit of existing users of
rcu_dereference_sk_user_data helper confirms our assumption.
Also, an RCU-protected sk_user_data is not likely to hold a pointer to a
char value or a pathological case of "struct { char c; }". To be safe, warn
when the flag-bit is set when setting sk_user_data to catch any future
misuses.
It is worth considering why clearing sk_user_data unconditionally is not an
option. There exist users, DRBD, NVMe, and Xen drivers being among them,
that rely on the pointer being copied when cloning the listening socket.
Potentially we could distinguish these users by checking if the listening
socket has been created in kernel-space via sock_create_kern, and hence has
sk_kern_sock flag set. However, this is not the case for NVMe and Xen
drivers, which create sockets without marking them as belonging to the
kernel.
Change-Id: I9b5d753faa1e1c3e105cb9071b22080831cbf061
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-3-jakub@cloudflare.com
It makes little sense for copying sk_user_data of reuseport_array during
sk_clone_lock(). This patch reuses the SK_USER_DATA_NOCOPY bit introduced in
commit f1ff5ce2cd5e ("net, sk_msg: Clear sk_user_data pointer on clone if tagged").
It is used to mark the sk_user_data is not supposed to be copied to its clone.
Although the cloned sk's sk_user_data will not be used/freed in
bpf_sk_reuseport_detach(), this change can still allow the cloned
sk's sk_user_data to be used by some other means.
Freeing the reuseport_array's sk_user_data does not require a rcu grace
period. Thus, the existing rcu_assign_sk_user_data_nocopy() is not
used.
Fixes: 5dc4c4b7d4 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY")
Change-Id: I89ee8dc9050163e88608c415119b21905280f6e5
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20200709061104.4018798-1-kafai@fb.com
Sometimes it's handy to know when the socket gets freed. In
particular, we'd like to try to use a smarter allocation of
ports for bpf_bind and explore the possibility of limiting
the number of SOCK_DGRAM sockets the process can have.
Implement BPF_CGROUP_INET_SOCK_RELEASE hook that triggers on
inet socket release. It triggers only for userspace sockets
(not in-kernel ones) and therefore has the same semantics as
the existing BPF_CGROUP_INET_SOCK_CREATE.
Change-Id: If57133e0fdbd3906b4335dd68b0be887397d2364
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200706230128.4073544-2-sdf@google.com
Without CONFIG_STACKTRACE stack_trace_save_tsk() is not defined. Let
get_callchain_entry_for_task() to always return NULL in such cases.
Fixes: fa28dcb82a38 ("bpf: Introduce helper bpf_get_task_stack()")
Reported-by: kernel test robot <lkp@intel.com>
Change-Id: I77d017b374bba282ad0e5a9239103d4a8373e68e
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200703024537.79971-1-songliubraving@fb.com
Fix build errors when CONFIG_INET is not set/enabled.
(.text+0x2b1b): undefined reference to `tcp_prot'
(.text+0x2b3b): undefined reference to `tcp_prot'
Change-Id: I7a9060b7427f412890dd0179c026fa7fcae3abde
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/b1a858ec-7e04-56bc-248a-62cb9bbee726@infradead.org
Introduce helper bpf_get_task_stack(), which dumps stack trace of given
task. This is different to bpf_get_stack(), which gets stack track of
current task. One potential use case of bpf_get_task_stack() is to call
it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file.
bpf_get_task_stack() uses stack_trace_save_tsk() instead of
get_perf_callchain() for kernel stack. The benefit of this choice is that
stack_trace_save_tsk() doesn't require changes in arch/. The downside of
using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the
stack trace to unsigned long array. For 32-bit systems, we need to
translate it to u64 array.
Change-Id: I8ed75e8c319732433a0ea1dd05951176ca81d1dd
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630062846.664389-3-songliubraving@fb.com
Sanitize and expose get/put_callchain_entry(). This would be used by bpf
stack map.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Change-Id: If8cb04efa03912f669d456ea06cfde5e5e9c1d2c
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630062846.664389-2-songliubraving@fb.com
/proc/net/tcp{4,6} uses jiffies for various computations.
Let us add bpf_jiffies64() helper to tracing program
so bpf_iter and other programs can use it.
Change-Id: I18cb1e7ecea12b3ffdc597fe6b97a5d2c8137e1e
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230808.3988073-1-yhs@fb.com
bpf_free_used_maps() or close(map_fd) will trigger map_free callback.
bpf_free_used_maps() is called after bpf prog is no longer executing:
bpf_prog_put->call_rcu->bpf_prog_free->bpf_free_used_maps.
Hence there is no need to call synchronize_rcu() to protect map elements.
Note that hash_of_maps and array_of_maps update/delete inner maps via
sys_bpf() that calls maybe_wait_bpf_programs() and synchronize_rcu().
Change-Id: Iac22753fc71080d3cee7931f11f8ab8a30fe96c0
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/bpf/20200630043343.53195-2-alexei.starovoitov@gmail.com
Add two tests for PTR_TO_BTF_ID vs. null ptr comparison,
one for PTR_TO_BTF_ID in the ctx structure and the
other for PTR_TO_BTF_ID after one level pointer chasing.
In both cases, the test ensures condition is not
removed.
For example, for this test
struct bpf_fentry_test_t {
struct bpf_fentry_test_t *a;
};
int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
{
if (arg == 0)
test7_result = 1;
return 0;
}
Before the previous verifier change, we have xlated codes:
int test7(long long unsigned int * ctx):
; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
0: (79) r1 = *(u64 *)(r1 +0)
; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
1: (b4) w0 = 0
2: (95) exit
After the previous verifier change, we have:
int test7(long long unsigned int * ctx):
; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
0: (79) r1 = *(u64 *)(r1 +0)
; if (arg == 0)
1: (55) if r1 != 0x0 goto pc+4
; test7_result = 1;
2: (18) r1 = map[id:6][0]+48
4: (b7) r2 = 1
5: (7b) *(u64 *)(r1 +0) = r2
; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
6: (b4) w0 = 0
7: (95) exit
Change-Id: I4bfad59a173ce4e838c6f6f494e85c0a1e8d0431
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630171241.2523875-1-yhs@fb.com
Wenbo reported an issue in [1] where a checking of null
pointer is evaluated as always false. In this particular
case, the program type is tp_btf and the pointer to
compare is a PTR_TO_BTF_ID.
The current verifier considers PTR_TO_BTF_ID always
reprents a non-null pointer, hence all PTR_TO_BTF_ID compares
to 0 will be evaluated as always not-equal, which resulted
in the branch elimination.
For example,
struct bpf_fentry_test_t {
struct bpf_fentry_test_t *a;
};
int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
{
if (arg == 0)
test7_result = 1;
return 0;
}
int BPF_PROG(test8, struct bpf_fentry_test_t *arg)
{
if (arg->a == 0)
test8_result = 1;
return 0;
}
In above bpf programs, both branch arg == 0 and arg->a == 0
are removed. This may not be what developer expected.
The bug is introduced by Commit cac616db39c2 ("bpf: Verifier
track null pointer branch_taken with JNE and JEQ"),
where PTR_TO_BTF_ID is considered to be non-null when evaluting
pointer vs. scalar comparison. This may be added
considering we have PTR_TO_BTF_ID_OR_NULL in the verifier
as well.
PTR_TO_BTF_ID_OR_NULL is added to explicitly requires
a non-NULL testing in selective cases. The current generic
pointer tracing framework in verifier always
assigns PTR_TO_BTF_ID so users does not need to
check NULL pointer at every pointer level like a->b->c->d.
We may not want to assign every PTR_TO_BTF_ID as
PTR_TO_BTF_ID_OR_NULL as this will require a null test
before pointer dereference which may cause inconvenience
for developers. But we could avoid branch elimination
to preserve original code intention.
This patch simply removed PTR_TO_BTD_ID from reg_type_not_null()
in verifier, which prevented the above branches from being eliminated.
[1]: https://lore.kernel.org/bpf/79dbb7c0-449d-83eb-5f4f-7af0cc269168@fb.com/T/
Fixes: cac616db39c2 ("bpf: Verifier track null pointer branch_taken with JNE and JEQ")
Reported-by: Wenbo Zhang <ethercflow@gmail.com>
Change-Id: Ifdd05e48cd123b397afeece6ee584d3834e20333
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200630171240.2523722-1-yhs@fb.com
Iterating over BPF links attached to network namespace in pre_exit hook is
not safe, even if there is just one. Once link gets auto-detached, that is
its back-pointer to net object is set to NULL, the link can be released and
freed without waiting on netns_bpf_mutex, effectively causing the list
element we are operating on to be freed.
This leads to use-after-free when trying to access the next element on the
list, as reported by KASAN. Bug can be triggered by destroying a network
namespace, while also releasing a link attached to this network namespace.
| ==================================================================
| BUG: KASAN: use-after-free in netns_bpf_pernet_pre_exit+0xd9/0x130
| Read of size 8 at addr ffff888119e0d778 by task kworker/u8:2/177
|
| CPU: 3 PID: 177 Comm: kworker/u8:2 Not tainted 5.8.0-rc1-00197-ga0c04c9d1008-dirty #776
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
| Workqueue: netns cleanup_net
| Call Trace:
| dump_stack+0x9e/0xe0
| print_address_description.constprop.0+0x3a/0x60
| ? netns_bpf_pernet_pre_exit+0xd9/0x130
| kasan_report.cold+0x1f/0x40
| ? netns_bpf_pernet_pre_exit+0xd9/0x130
| netns_bpf_pernet_pre_exit+0xd9/0x130
| cleanup_net+0x30b/0x5b0
| ? unregister_pernet_device+0x50/0x50
| ? rcu_read_lock_bh_held+0xb0/0xb0
| ? _raw_spin_unlock_irq+0x24/0x50
| process_one_work+0x4d1/0xa10
| ? lock_release+0x3e0/0x3e0
| ? pwq_dec_nr_in_flight+0x110/0x110
| ? rwlock_bug.part.0+0x60/0x60
| worker_thread+0x7a/0x5c0
| ? process_one_work+0xa10/0xa10
| kthread+0x1e3/0x240
| ? kthread_create_on_node+0xd0/0xd0
| ret_from_fork+0x1f/0x30
|
| Allocated by task 280:
| save_stack+0x1b/0x40
| __kasan_kmalloc.constprop.0+0xc2/0xd0
| netns_bpf_link_create+0xfe/0x650
| __do_sys_bpf+0x153a/0x2a50
| do_syscall_64+0x59/0x300
| entry_SYSCALL_64_after_hwframe+0x44/0xa9
|
| Freed by task 198:
| save_stack+0x1b/0x40
| __kasan_slab_free+0x12f/0x180
| kfree+0xed/0x350
| process_one_work+0x4d1/0xa10
| worker_thread+0x7a/0x5c0
| kthread+0x1e3/0x240
| ret_from_fork+0x1f/0x30
|
| The buggy address belongs to the object at ffff888119e0d700
| which belongs to the cache kmalloc-192 of size 192
| The buggy address is located 120 bytes inside of
| 192-byte region [ffff888119e0d700, ffff888119e0d7c0)
| The buggy address belongs to the page:
| page:ffffea0004678340 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
| flags: 0x2fffe0000000200(slab)
| raw: 02fffe0000000200 ffffea00045ba8c0 0000000600000006 ffff88811a80ea80
| raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
| page dumped because: kasan: bad access detected
|
| Memory state around the buggy address:
| ffff888119e0d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
| ffff888119e0d680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
| >ffff888119e0d700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
| ^
| ffff888119e0d780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
| ffff888119e0d800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
| ==================================================================
Remove the "fast-path" for releasing a link that got auto-detached by a
dying network namespace to fix it. This way as long as link is on the list
and netns_bpf mutex is held, we have a guarantee that link memory can be
accessed.
An alternative way to fix this issue would be to safely iterate over the
list of links and ensure there is no access to link object after detaching
it. But, at the moment, optimizing synchronization overhead on link release
without a workload in mind seems like an overkill.
Fixes: ab53cad90eb1 ("bpf, netns: Keep a list of attached bpf_link's")
Change-Id: Ib1f668d2fba2b3d16806608548e3335a9274a866
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200630164541.1329993-1-jakub@cloudflare.com
Using BPF_PROG_DETACH on a flow dissector program supports neither
attach_flags nor attach_bpf_fd. Yet no value is enforced for them.
Enforce that attach_flags are zero, and require the current program
to be passed via attach_bpf_fd. This allows us to remove the check
for CAP_SYS_ADMIN, since userspace can now no longer remove
arbitrary flow dissector programs.
Fixes: b27f7bb590ba ("flow_dissector: Move out netns_bpf prog callbacks")
Change-Id: I2eaf851ab883dc315c642bf6ea26f529a178e5d3
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200629095630.7933-3-lmb@cloudflare.com
Using BPF_PROG_ATTACH on a flow dissector program supports neither
target_fd, attach_flags or replace_bpf_fd but accepts any value.
Enforce that all of them are zero. This is fine for replace_bpf_fd
since its presence is indicated by BPF_F_REPLACE. It's more
problematic for target_fd, since zero is a valid fd. Should we
want to use the flag later on we'd have to add an exception for
fd 0. The alternative is to force a value like -1. This requires
more changes to tests. There is also precedent for using 0,
since bpf_iter uses this for target_fd as well.
Fixes: b27f7bb590ba ("flow_dissector: Move out netns_bpf prog callbacks")
Change-Id: Ic950b6164e2ad5405669794b069376a98521a67f
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200629095630.7933-2-lmb@cloudflare.com
To support multi-prog link-based attachments for new netns attach types, we
need to keep track of more than one bpf_link per attach type. Hence,
convert net->bpf.links into a list, that currently can be either empty or
have just one item.
Instead of reusing bpf_prog_list from bpf-cgroup, we link together
bpf_netns_link's themselves. This makes list management simpler as we don't
have to allocate, initialize, and later release list elements. We can do
this because multi-prog attachment will be available only for bpf_link, and
we don't need to build a list of programs attached directly and indirectly
via links.
No functional changes intended.
Change-Id: I64d0c6fe7c9fa3a50b81071345bb7e9458df1aff
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200625141357.910330-4-jakub@cloudflare.com
Prepare for having multi-prog attachments for new netns attach types by
storing programs to run in a bpf_prog_array, which is well suited for
iterating over programs and running them in sequence.
After this change bpf(PROG_QUERY) may block to allocate memory in
bpf_prog_array_copy_to_user() for collected program IDs. This forces a
change in how we protect access to the attached program in the query
callback. Because bpf_prog_array_copy_to_user() can sleep, we switch from
an RCU read lock to holding a mutex that serializes updaters.
Because we allow only one BPF flow_dissector program to be attached to
netns at all times, the bpf_prog_array pointed by net->bpf.run_array is
always either detached (null) or one element long.
No functional changes intended.
Change-Id: I9c35fccef7fc323a73f49ba3066b60baa7d1fb03
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200625141357.910330-3-jakub@cloudflare.com
Prepare for using bpf_prog_array to store attached programs by moving out
code that updates the attached program out of flow dissector.
Managing bpf_prog_array is more involved than updating a single bpf_prog
pointer. This will let us do it all from one place, bpf/net_namespace.c, in
the subsequent patch.
No functional change intended.
Change-Id: I3e347b0401b328c2bf355c6559c4fe43ee5cd19d
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200625141357.910330-2-jakub@cloudflare.com
BPF ringbuf assumes the size to be a multiple of page size and the power of
2 value. The latter is important to avoid division while calculating position
inside the ring buffer and using (N-1) mask instead. This patch fixes omission
to enforce power-of-2 size rule.
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Change-Id: Ic4b87200d91936c3302ab0687f6b187bac7ce60b
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200630061500.1804799-1-andriin@fb.com
To ensure btf_ctx_access() is safe the verifier checks that the BTF
arg type is an int, enum, or pointer. When the function does the
BTF arg lookup it uses the calculation 'arg = off / 8' using the
fact that registers are 8B. This requires that the first arg is
in the first reg, the second in the second, and so on. However,
for __int128 the arg will consume two registers by default LLVM
implementation. So this will cause the arg layout assumed by the
'arg = off / 8' calculation to be incorrect.
Because __int128 is uncommon this patch applies the easiest fix and
will force int types to be sizeof(u64) or smaller so that they will
fit in a single register.
v2: remove unneeded parens per Andrii's feedback
Fixes: 9e15db66136a1 ("bpf: Implement accurate raw_tp context access via BTF")
Change-Id: Iaa7a6fbaf8d4746c80bf4217bf518aba9e1a83b3
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/159303723962.11287.13309537171132420717.stgit@john-Precision-5820-Tower
The helper is used in tracing programs to cast a socket
pointer to a udp6_sock pointer.
The return value could be NULL if the casting is illegal.
Change-Id: If6ef5992dcf07b5b8171c8221078d0f96fdce956
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200623230815.3988481-1-yhs@fb.com
Three more helpers are added to cast a sock_common pointer to
an tcp_sock, tcp_timewait_sock or a tcp_request_sock for
tracing programs.
Change-Id: I43e998912a1e786d8f96e01e9a331554832d29be
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230811.3988277-1-yhs@fb.com
