selftests/bpf: Use bpf_{btf,link,map,prog}_get_info_by_fd()

Use the new type-safe wrappers around bpf_obj_get_info_by_fd().
Fix a prog/map mixup in prog_holds_map().

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230214231221.249277-6-iii@linux.ibm.com

selftests/bpf: mmap: Use runtime page size

Replace hardcoded 4096 with runtime value in the userspace part of
the test and set bpf table sizes dynamically according to the value.

Do not switch to ASSERT macros, keep CHECK, for consistency with the
rest of the test. Can be a separate cleanup patch.

Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210408061310.95877-5-yauheni.kaliuta@redhat.com

selftests/bpf: Fix segmentation fault in test_progs

test_progs reports the segmentation fault as below:

$ sudo ./test_progs -t mmap --verbose
test_mmap:PASS:skel_open_and_load 0 nsec
[...]
test_mmap:PASS:adv_mmap1 0 nsec
test_mmap:PASS:adv_mmap2 0 nsec
test_mmap:PASS:adv_mmap3 0 nsec
test_mmap:PASS:adv_mmap4 0 nsec
Segmentation fault

This issue was triggered because mmap() and munmap() used inconsistent
length parameters; mmap() creates a new mapping of 3 * page_size, but the
length parameter set in the subsequent re-map and munmap() functions is
4 * page_size; this leads to the destruction of the process space.

To fix this issue, first create 4 pages of anonymous mapping, then do all
the mmap() with MAP_FIXED.

Another issue is that when unmap the second page fails, the length
parameter to delete tmp1 mappings should be 4 * page_size.

Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200810153940.125508-1-Jianlin.Lv@arm.com

bpf: Prevent mmap()'ing read-only maps as writable

As discussed in [0], it's dangerous to allow mapping BPF map, that's meant to
be frozen and is read-only on BPF program side, because that allows user-space
to actually store a writable view to the page even after it is frozen. This is
exacerbated by BPF verifier making a strong assumption that contents of such
frozen map will remain unchanged. To prevent this, disallow mapping
BPF_F_RDONLY_PROG mmap()'able BPF maps as writable, ever.

[0] https://lore.kernel.org/bpf/CAEf4BzYGWYhXdp6BJ7_=9OQPJxQpgug080MMjdSB72i9R+5c6g@mail.gmail.com/

Fixes: fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/bpf/20200519053824.1089415-1-andriin@fb.com

bpf: Fix bug in mmap() implementation for BPF array map

mmap() subsystem allows user-space application to memory-map region with
initial page offset. This wasn't taken into account in initial implementation
of BPF array memory-mapping. This would result in wrong pages, not taking into
account requested page shift, being memory-mmaped into user-space. This patch
fixes this gap and adds a test for such scenario.

Fixes: fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200512235925.3817805-1-andriin@fb.com

selftests/bpf: Validate frozen map contents stays frozen

Test that frozen and mmap()'ed BPF map can't be mprotect()'ed as writable or
executable memory. Also validate that "downgrading" from writable to read-only
doesn't screw up internal writable count accounting for the purposes of map
freezing.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200410202613.3679837-2-andriin@fb.com

bpftool, selftests/bpf: Embed object file inside skeleton

Embed contents of BPF object file used for BPF skeleton generation inside
skeleton itself. This allows to keep BPF object file and its skeleton in sync
at all times, and simpifies skeleton instantiation.

Also switch existing selftests to not require BPF_EMBED_OBJ anymore.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191218052552.2915188-2-andriin@fb.com

selftests/bpf: Convert few more selftest to skeletons

Convert few more selftests to use generated BPF skeletons as a demonstration
on how to use it.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-16-andriin@fb.com

selftests/bpf: Add BPF_TYPE_MAP_ARRAY mmap() tests

Add selftests validating mmap()-ing BPF array maps: both single-element and
multi-element ones. Check that plain bpf_map_update_elem() and
bpf_map_lookup_elem() work correctly with memory-mapped array. Also convert
CO-RE relocation tests to use memory-mapped views of global data.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191117172806.2195367-6-andriin@fb.com