linux-stable.git/samples/bpf, branch v5.8.2

samples: bpf: Fix bpf programs with kprobe/sys_connect event

2020-08-19T06:26:33+00:00

[ Upstream commit af9bd3e3331b8af42b6606c75797d041ab39380c ]

Currently, BPF programs with kprobe/sys_connect does not work properly.

Commit 34745aed515c ("samples/bpf: fix kprobe attachment issue on x64")
This commit modifies the bpf_load behavior of kprobe events in the x64
architecture. If the current kprobe event target starts with "sys_*",
add the prefix "__x64_" to the front of the event.

Appending "__x64_" prefix with kprobe/sys_* event was appropriate as a
solution to most of the problems caused by the commit below.

    commit d5a00528b58c ("syscalls/core, syscalls/x86: Rename struct
    pt_regs-based sys_*() to __x64_sys_*()")

However, there is a problem with the sys_connect kprobe event that does
not work properly. For __sys_connect event, parameters can be fetched
normally, but for __x64_sys_connect, parameters cannot be fetched.

    ffffffff818d3520 <__x64_sys_connect>:
    ffffffff818d3520: e8 fb df 32 00        callq   0xffffffff81c01520
    <__fentry__>
    ffffffff818d3525: 48 8b 57 60           movq    96(%rdi), %rdx
    ffffffff818d3529: 48 8b 77 68           movq    104(%rdi), %rsi
    ffffffff818d352d: 48 8b 7f 70           movq    112(%rdi), %rdi
    ffffffff818d3531: e8 1a ff ff ff        callq   0xffffffff818d3450
    <__sys_connect>
    ffffffff818d3536: 48 98                 cltq
    ffffffff818d3538: c3                    retq
    ffffffff818d3539: 0f 1f 80 00 00 00 00  nopl    (%rax)

As the assembly code for __x64_sys_connect shows, parameters should be
fetched and set into rdi, rsi, rdx registers prior to calling
__sys_connect.

Because of this problem, this commit fixes the sys_connect event by
first getting the value of the rdi register and then the value of the
rdi, rsi, and rdx register through an offset based on that value.

Fixes: 34745aed515c ("samples/bpf: fix kprobe attachment issue on x64")
Signed-off-by: Daniel T. Lee 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200707184855.30968-2-danieltimlee@gmail.com
Signed-off-by: Sasha Levin

bpf: Fix fds_example SIGSEGV error

2020-08-19T06:26:19+00:00

[ Upstream commit eef8a42d6ce087d1c81c960ae0d14f955b742feb ]

The `BPF_LOG_BUF_SIZE`'s value is `UINT32_MAX >> 8`, so define an array
with it on stack caused an overflow.

Signed-off-by: Wenbo Zhang 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200710092035.28919-1-ethercflow@gmail.com
Signed-off-by: Sasha Levin

bpf, xdp, samples: Fix null pointer dereference in *_user code

2020-06-16T12:55:35+00:00

Memset on the pointer right after malloc can cause a NULL pointer
deference if it failed to allocate memory. A simple fix is to
replace malloc()/memset() pair with a simple call to calloc().

Fixes: 0fca931a6f21 ("samples/bpf: program demonstrating access to xdp_rxq_info")
Signed-off-by: Gaurav Singh 
Signed-off-by: Daniel Borkmann 
Acked-by: Jesper Dangaard Brouer 
Acked-by: John Fastabend

samples, bpf: Refactor kprobe, tail call kern progs map definition

2020-05-19T15:13:03+00:00

Because the previous two commit replaced the bpf_load implementation of
the user program with libbpf, the corresponding kernel program's MAP
definition can be replaced with new BTF-defined map syntax.

This commit only updates the samples which uses libbpf API for loading
bpf program not with bpf_load.

Signed-off-by: Daniel T. Lee 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200516040608.1377876-6-danieltimlee@gmail.com

samples, bpf: Add tracex7 test file to .gitignore

2020-05-19T15:13:00+00:00

This commit adds tracex7 test file (testfile.img) to .gitignore which
comes from test_override_return.sh.

Signed-off-by: Daniel T. Lee 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200516040608.1377876-5-danieltimlee@gmail.com

samples, bpf: Refactor tail call user progs with libbpf

2020-05-19T15:12:56+00:00

BPF tail call uses the BPF_MAP_TYPE_PROG_ARRAY type map for calling
into other BPF programs and this PROG_ARRAY should be filled prior to
use. Currently, samples with the PROG_ARRAY type MAP fill this program
array with bpf_load. For bpf_load to fill this map, kernel BPF program
must specify the section with specific format of /
(e.g. SEC("socket/0"))

But by using libbpf instead of bpf_load, user program can specify which
programs should be added to PROG_ARRAY. The advantage of this approach
is that you can selectively add only the programs you want, rather than
adding all of them to PROG_ARRAY, and it's much more intuitive than the
traditional approach.

This commit refactors user programs with the PROG_ARRAY type MAP with
libbpf instead of using bpf_load.

Signed-off-by: Daniel T. Lee 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200516040608.1377876-4-danieltimlee@gmail.com

samples, bpf: Refactor kprobe tracing user progs with libbpf

2020-05-19T15:12:53+00:00

Currently, the kprobe BPF program attachment method for bpf_load is
quite old. The implementation of bpf_load "directly" controls and
manages(create, delete) the kprobe events of DEBUGFS. On the other hand,
using using the libbpf automatically manages the kprobe event.
(under bpf_link interface)

By calling bpf_program__attach(_kprobe) in libbpf, the corresponding
kprobe is created and the BPF program will be attached to this kprobe.
To remove this, by simply invoking bpf_link__destroy will clean up the
event.

This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with
libbpf using bpf_link interface and bpf_program__attach.

tracex2_kern.c, which tracks system calls (sys_*), has been modified to
append prefix depending on architecture.

Signed-off-by: Daniel T. Lee 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200516040608.1377876-3-danieltimlee@gmail.com

samples, bpf: Refactor pointer error check with libbpf

2020-05-19T15:12:49+00:00

Current method of checking pointer error is not user friendly.
Especially the __must_check define makes this less intuitive.

Since, libbpf has an API libbpf_get_error() which checks pointer error,
this commit refactors existing pointer error check logic with libbpf.

Signed-off-by: Daniel T. Lee 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200516040608.1377876-2-danieltimlee@gmail.com

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

2020-05-15T20:48:59+00:00

Move the bpf verifier trace check into the new switch statement in
HEAD.

Resolve the overlapping changes in hinic, where bug fixes overlap
the addition of VF support.

Signed-off-by: David S. Miller

samples/bpf: xdp_redirect_cpu: Set MAX_CPUS according to NR_CPUS

2020-05-15T01:27:00+00:00

xdp_redirect_cpu is currently failing in bpf_prog_load_xattr()
allocating cpu_map map if CONFIG_NR_CPUS is less than 64 since
cpu_map_alloc() requires max_entries to be less than NR_CPUS.
Set cpu_map max_entries according to NR_CPUS in xdp_redirect_cpu_kern.c
and get currently running cpus in xdp_redirect_cpu_user.c

Signed-off-by: Lorenzo Bianconi 
Signed-off-by: Alexei Starovoitov 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/374472755001c260158c4e4b22f193bdd3c56fb7.1589300442.git.lorenzo@kernel.org