When using make kselftest TARGETS=bpf, tools/bpf is built with
MAKEFLAGS=rR, which causes $(COMPILE.c) to be undefined, which in turn
causes the build to fail with
CC kselftest/bpf/tools/build/bpftool/map_perf_ring.o
/bin/sh: 1: -MMD: not found
Fix by using $(CC) $(CFLAGS) -c instead of $(COMPILE.c).
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200602175649.2501580-2-iii@linux.ibm.com
btf__parse_raw and btf__parse_elf return negative error numbers wrapped
in an ERR_PTR, so the extracted value needs to be negated before passing
them to strerror which expects a positive error number.
Before:
Error: failed to load BTF from .../vmlinux: Unknown error -2
After:
Error: failed to load BTF from .../vmlinux: No such file or directory
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200525135421.4154-1-tklauser@distanz.ch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Following the introduction of CAP_BPF, and the switch from CAP_SYS_ADMIN
to other capabilities for various BPF features, update the capability
checks (and potentially, drops) in bpftool for feature probes. Because
bpftool and/or the system might not know of CAP_BPF yet, some caution is
necessary:
- If compiled and run on a system with CAP_BPF, check CAP_BPF,
CAP_SYS_ADMIN, CAP_PERFMON, CAP_NET_ADMIN.
- Guard against CAP_BPF being undefined, to allow compiling bpftool from
latest sources on older systems. If the system where feature probes
are run does not know of CAP_BPF, stop checking after CAP_SYS_ADMIN,
as this should be the only capability required for all the BPF
probing.
- If compiled from latest sources on a system without CAP_BPF, but later
executed on a newer system with CAP_BPF knowledge, then we only test
CAP_SYS_ADMIN. Some probes may fail if the bpftool process has
CAP_SYS_ADMIN but misses the other capabilities. The alternative would
be to redefine the value for CAP_BPF in bpftool, but this does not
look clean, and the case sounds relatively rare anyway.
Note that libcap offers a cap_to_name() function to retrieve the name of
a given capability (e.g. "cap_sys_admin"). We do not use it because
deriving the names from the macros looks simpler than using
cap_to_name() (doing a strdup() on the string) + cap_free() + handling
the case of failed allocations, when we just want to use the name of the
capability in an error message.
The checks when compiling without libcap (i.e. root versus non-root) are
unchanged.
v2:
- Do not allocate cap_list dynamically.
- Drop BPF-related capabilities when running with "unprivileged", even
if we didn't have the full set in the first place (in v1, we would
skip dropping them in that case).
- Keep track of what capabilities we have, print the names of the
missing ones for privileged probing.
- Attempt to drop only the capabilities we actually have.
- Rename a couple variables.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200523010247.20654-1-quentin@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This is a clean-up for the formatting of the do_help functions for
bpftool's subcommands. The following fixes are included:
- Do not use argv[-2] for "iter" help message, as the help is shown by
default if no "iter" action is selected, resulting in messages looking
like "./bpftool bpftool pin...".
- Do not print unused HELP_SPEC_PROGRAM in help message for "bpftool
link".
- Andrii used argument indexing to avoid having multiple occurrences of
bin_name and argv[-2] in the fprintf() for the help message, for
"bpftool gen" and "bpftool link". Let's reuse this for all other help
functions. We can remove up to thirty arguments for the "bpftool map"
help message.
- Harmonise all functions, e.g. use ending quotes-comma on a separate
line.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200523010751.23465-1-quentin@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In Cilium we've recently switched to make use of bpf_jiffies64() for
parts of our tc and XDP datapath since bpf_ktime_get_ns() is more
expensive and high-precision is not needed for our timeouts we have
anyway. Our agent has a probe manager which picks up the json of
bpftool's feature probe and we also use the macro output in our C
programs e.g. to have workarounds when helpers are not available on
older kernels.
Extend the kernel config info dump to also include the kernel's
CONFIG_HZ, and rework the probe_kernel_image_config() for allowing a
macro dump such that CONFIG_HZ can be propagated to BPF C code as a
simple define if available via config. Latter allows to have _compile-
time_ resolution of jiffies <-> sec conversion in our code since all
are propagated as known constants.
Given we cannot generally assume availability of kconfig everywhere,
we also have a kernel hz probe [0] as a fallback. Potentially, bpftool
could have an integrated probe fallback as well, although to derive it,
we might need to place it under 'bpftool feature probe full' or similar
given it would slow down the probing process overall. Yet 'full' doesn't
fit either for us since we don't want to pollute the kernel log with
warning messages from bpf_probe_write_user() and bpf_trace_printk() on
agent startup; I've left it out for the time being.
[0] https://github.com/cilium/cilium/blob/master/bpf/cilium-probe-kernel-hz.c
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200513075849.20868-1-daniel@iogearbox.net
Bring minor improvements to bpftool documentation. Fix or harmonise
formatting, update map types (including in interactive help), improve
description for "map create", fix a build warning due to a missing line
after the double-colon for the "bpftool prog profile" example,
complete/harmonise/sort the list of related bpftool man pages in
footers.
v2:
- Remove (instead of changing) mark-up on "value" in bpftool-map.rst,
when it does not refer to something passed on the command line.
- Fix an additional typo ("hexadeximal") in the same file.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200511161536.29853-3-quentin@isovalent.com
runqslower doesn't specify include path for uapi/bpf.h. This causes the
following warning:
In file included from runqslower.c:10:
.../tools/testing/selftests/bpf/tools/include/bpf/bpf.h:234:38:
warning: 'enum bpf_stats_type' declared inside parameter list will not
be visible outside of this definition or declaration
234 | LIBBPF_API int bpf_enable_stats(enum bpf_stats_type type);
Fix this by adding -I tools/includ/uapi to the Makefile.
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, only one command is supported
bpftool iter pin <bpf_prog.o> <path>
It will pin the trace/iter bpf program in
the object file <bpf_prog.o> to the <path>
where <path> should be on a bpffs mount.
For example,
$ bpftool iter pin ./bpf_iter_ipv6_route.o \
/sys/fs/bpf/my_route
User can then do a `cat` to print out the results:
$ cat /sys/fs/bpf/my_route
fe800000000000000000000000000000 40 00000000000000000000000000000000 ...
00000000000000000000000000000000 00 00000000000000000000000000000000 ...
00000000000000000000000000000001 80 00000000000000000000000000000000 ...
fe800000000000008c0162fffebdfd57 80 00000000000000000000000000000000 ...
ff000000000000000000000000000000 08 00000000000000000000000000000000 ...
00000000000000000000000000000000 00 00000000000000000000000000000000 ...
The implementation for ipv6_route iterator is in one of subsequent
patches.
This patch also added BPF_LINK_TYPE_ITER to link query.
In the future, we may add additional parameters to pin command
by parameterizing the bpf iterator. For example, a map_id or pid
may be added to let bpf program only traverses a single map or task,
similar to kernel seq_file single_open().
We may also add introspection command for targets/iterators by
leveraging the bpf_iter itself.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200509175920.2477247-1-yhs@fb.com
Alexei Starovoitov says:
====================
pull-request: bpf-next 2020-05-01 (v2)
The following pull-request contains BPF updates for your *net-next* tree.
We've added 61 non-merge commits during the last 6 day(s) which contain
a total of 153 files changed, 6739 insertions(+), 3367 deletions(-).
The main changes are:
1) pulled work.sysctl from vfs tree with sysctl bpf changes.
2) bpf_link observability, from Andrii.
3) BTF-defined map in map, from Andrii.
4) asan fixes for selftests, from Andrii.
5) Allow bpf_map_lookup_elem for SOCKMAP and SOCKHASH, from Jakub.
6) production cloudflare classifier as a selftes, from Lorenz.
7) bpf_ktime_get_*_ns() helper improvements, from Maciej.
8) unprivileged bpftool feature probe, from Quentin.
9) BPF_ENABLE_STATS command, from Song.
10) enable bpf_[gs]etsockopt() helpers for sock_ops progs, from Stanislav.
11) enable a bunch of common helpers for cg-device, sysctl, sockopt progs,
from Stanislav.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
There is demand for a way to identify what BPF helper functions are
available to unprivileged users. To do so, allow unprivileged users to
run "bpftool feature probe" to list BPF-related features. This will only
show features accessible to those users, and may not reflect the full
list of features available (to administrators) on the system.
To avoid the case where bpftool is inadvertently run as non-root and
would list only a subset of the features supported by the system when it
would be expected to list all of them, running as unprivileged is gated
behind the "unprivileged" keyword passed to the command line. When used
by a privileged user, this keyword allows to drop the CAP_SYS_ADMIN and
to list the features available to unprivileged users. Note that this
addsd a dependency on libpcap for compiling bpftool.
Note that there is no particular reason why the probes were restricted
to root, other than the fact I did not need them for unprivileged and
did not bother with the additional checks at the time probes were added.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200429144506.8999-3-quentin@isovalent.com
The "full_mode" variable used for switching between full or partial
feature probing (i.e. with or without probing helpers that will log
warnings in kernel logs) was piped from the main do_probe() function
down to probe_helpers_for_progtype(), where it is needed.
Define it as a global variable: the calls will be more readable, and if
other similar flags were to be used in the future, we could use global
variables as well instead of extending again the list of arguments with
new flags.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200429144506.8999-2-quentin@isovalent.com
- add SPDX header;
- adjust title markup;
- mark code blocks and literals as such;
- use footnote markup;
- mark tables as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reorder include paths to ensure that runqslower sources are picking up
vmlinux.h, generated by runqslower's own Makefile. When runqslower is built
from selftests/bpf, due to current -I$(BPF_INCLUDE) -I$(OUTPUT) ordering, it
might pick up not-yet-complete vmlinux.h, generated by selftests Makefile,
which could lead to compilation errors like [0]. So ensure that -I$(OUTPUT)
goes first and rely on runqslower's Makefile own dependency chain to ensure
vmlinux.h is properly completed before source code relying on it is compiled.
[0] https://travis-ci.org/github/libbpf/libbpf/jobs/677905925
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200422012407.176303-1-andriin@fb.com
In commit 65c9362859 ("bpftool: Add struct_ops support") a new
type of command named struct_ops has been added. This command requires
a kernel with CONFIG_DEBUG_INFO_BTF=y set and for retrieving BTF info
in bpftool, the helper get_btf_vmlinux() is used.
When running this command on kernel without BTF debug info, this will
lead to 'btf_vmlinux' variable being an invalid(error) pointer. And by
this, btf_free() causes a segfault when executing 'bpftool struct_ops'.
This commit adds pointer validation with IS_ERR not to free invalid
pointer, and this will fix the segfault issue.
Fixes: 65c9362859 ("bpftool: Add struct_ops support")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200410020612.2930667-1-danieltimlee@gmail.com
Ilya Leoshkevich
Jakub Sitnicki
Tobias Klauser
Quentin Monnet
Daniel Borkmann
Song Liu
Yonghong Song
David S. Miller
Andrii Nakryiko
Mauro Carvalho Chehab
Jagadeesh Pagadala
Martin KaFai Lau
Daniel T. Lee