linux.git/tools/lib/bpf/btf.c, branch v6.9 Linux kernel source tree libbpf: Correct debug message in btf__load_vmlinux_btf 2024-03-04T13:33:51+00:00 Chen Shen peterchenshen@gmail.com 2024-03-02T06:22:18+00:00 25703adf45f8430ec59effa20920c80139d13cdc In the function btf__load_vmlinux_btf, the debug message incorrectly refers to 'path' instead of 'sysfs_btf_path'. Signed-off-by: Chen Shen <peterchenshen@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20240302062218.3587-1-peterchenshen@gmail.com 
In the function btf__load_vmlinux_btf, the debug message incorrectly
refers to 'path' instead of 'sysfs_btf_path'.

Signed-off-by: Chen Shen <peterchenshen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240302062218.3587-1-peterchenshen@gmail.com
libbpf: Add missed btf_ext__raw_data() API 2024-02-01T21:16:12+00:00 Andrii Nakryiko andrii@kernel.org 2024-02-01T17:20:26+00:00 b9551da8cf3ade01a50316df8a618fd945723ee0 Another API that was declared in libbpf.map but actual implementation was missing. btf_ext__get_raw_data() was intended as a discouraged alias to consistently-named btf_ext__raw_data(), so make this an actuality. Fixes: 20eccf29e297 ("libbpf: hide and discourage inconsistently named getters") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-5-andrii@kernel.org 
Another API that was declared in libbpf.map but actual implementation
was missing. btf_ext__get_raw_data() was intended as a discouraged alias
to consistently-named btf_ext__raw_data(), so make this an actuality.

Fixes: 20eccf29e297 ("libbpf: hide and discourage inconsistently named getters")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240201172027.604869-5-andrii@kernel.org
libbpf: Add btf__new_split() API that was declared but not implemented 2024-02-01T21:16:12+00:00 Andrii Nakryiko andrii@kernel.org 2024-02-01T17:20:25+00:00 c81a8ab196b5083d5109a51585fcc24fa2055a77 Seems like original commit adding split BTF support intended to add btf__new_split() API, and even declared it in libbpf.map, but never added (trivial) implementation. Fix this. Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240201172027.604869-4-andrii@kernel.org 
Seems like original commit adding split BTF support intended to add
btf__new_split() API, and even declared it in libbpf.map, but never
added (trivial) implementation. Fix this.

Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240201172027.604869-4-andrii@kernel.org
libbpf: Add some details for BTF parsing failures 2024-01-30T00:42:42+00:00 Ian Rogers irogers@google.com 2024-01-25T23:18:40+00:00 f2e4040c82d3fddd11fa7c64e8f810e6f9cb7460 As CONFIG_DEBUG_INFO_BTF is default off the existing "failed to find valid kernel BTF" message makes diagnosing the kernel build issue somewhat cryptic. Add a little more detail with the hope of helping users. Before: ``` libbpf: failed to find valid kernel BTF libbpf: Error loading vmlinux BTF: -3 ``` After not accessible: ``` libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled? libbpf: failed to find valid kernel BTF libbpf: Error loading vmlinux BTF: -3 ``` After not readable: ``` libbpf: failed to read kernel BTF from (/sys/kernel/btf/vmlinux): -1 ``` Closes: https://lore.kernel.org/bpf/CAP-5=fU+DN_+Y=Y4gtELUsJxKNDDCOvJzPHvjUVaUoeFAzNnig@mail.gmail.com/ Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240125231840.1647951-1-irogers@google.com 
As CONFIG_DEBUG_INFO_BTF is default off the existing "failed to find
valid kernel BTF" message makes diagnosing the kernel build issue somewhat
cryptic. Add a little more detail with the hope of helping users.

Before:
```
libbpf: failed to find valid kernel BTF
libbpf: Error loading vmlinux BTF: -3
```

After not accessible:
```
libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?
libbpf: failed to find valid kernel BTF
libbpf: Error loading vmlinux BTF: -3
```

After not readable:
```
libbpf: failed to read kernel BTF from (/sys/kernel/btf/vmlinux): -1
```

Closes: https://lore.kernel.org/bpf/CAP-5=fU+DN_+Y=Y4gtELUsJxKNDDCOvJzPHvjUVaUoeFAzNnig@mail.gmail.com/

Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240125231840.1647951-1-irogers@google.com
libbpf: Wire up BPF token support at BPF object level 2024-01-25T00:21:02+00:00 Andrii Nakryiko andrii@kernel.org 2024-01-24T02:21:22+00:00 6b434b61b4d9e0e59f2947ce0f58f6fb4de048d8 Add BPF token support to BPF object-level functionality. BPF token is supported by BPF object logic either as an explicitly provided BPF token from outside (through BPF FS path), or implicitly (unless prevented through bpf_object_open_opts). Implicit mode is assumed to be the most common one for user namespaced unprivileged workloads. The assumption is that privileged container manager sets up default BPF FS mount point at /sys/fs/bpf with BPF token delegation options (delegate_{cmds,maps,progs,attachs} mount options). BPF object during loading will attempt to create BPF token from /sys/fs/bpf location, and pass it for all relevant operations (currently, map creation, BTF load, and program load). In this implicit mode, if BPF token creation fails due to whatever reason (BPF FS is not mounted, or kernel doesn't support BPF token, etc), this is not considered an error. BPF object loading sequence will proceed with no BPF token. In explicit BPF token mode, user provides explicitly custom BPF FS mount point path. In such case, BPF object will attempt to create BPF token from provided BPF FS location. If BPF token creation fails, that is considered a critical error and BPF object load fails with an error. Libbpf provides a way to disable implicit BPF token creation, if it causes any troubles (BPF token is designed to be completely optional and shouldn't cause any problems even if provided, but in the world of BPF LSM, custom security logic can be installed that might change outcome depending on the presence of BPF token). To disable libbpf's default BPF token creation behavior user should provide either invalid BPF token FD (negative), or empty bpf_token_path option. BPF token presence can influence libbpf's feature probing, so if BPF object has associated BPF token, feature probing is instructed to use BPF object-specific feature detection cache and token FD. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20240124022127.2379740-26-andrii@kernel.org 
Add BPF token support to BPF object-level functionality.

BPF token is supported by BPF object logic either as an explicitly
provided BPF token from outside (through BPF FS path), or implicitly
(unless prevented through bpf_object_open_opts).

Implicit mode is assumed to be the most common one for user namespaced
unprivileged workloads. The assumption is that privileged container
manager sets up default BPF FS mount point at /sys/fs/bpf with BPF token
delegation options (delegate_{cmds,maps,progs,attachs} mount options).
BPF object during loading will attempt to create BPF token from
/sys/fs/bpf location, and pass it for all relevant operations
(currently, map creation, BTF load, and program load).

In this implicit mode, if BPF token creation fails due to whatever
reason (BPF FS is not mounted, or kernel doesn't support BPF token,
etc), this is not considered an error. BPF object loading sequence will
proceed with no BPF token.

In explicit BPF token mode, user provides explicitly custom BPF FS mount
point path. In such case, BPF object will attempt to create BPF token
from provided BPF FS location. If BPF token creation fails, that is
considered a critical error and BPF object load fails with an error.

Libbpf provides a way to disable implicit BPF token creation, if it
causes any troubles (BPF token is designed to be completely optional and
shouldn't cause any problems even if provided, but in the world of BPF
LSM, custom security logic can be installed that might change outcome
depending on the presence of BPF token). To disable libbpf's default BPF
token creation behavior user should provide either invalid BPF token FD
(negative), or empty bpf_token_path option.

BPF token presence can influence libbpf's feature probing, so if BPF
object has associated BPF token, feature probing is instructed to use
BPF object-specific feature detection cache and token FD.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-26-andrii@kernel.org
libbpf: Add basic BTF sanity validation 2023-09-08T15:42:17+00:00 Andrii Nakryiko andrii@kernel.org 2023-08-25T20:21:52+00:00 3903802bb99a263a3c26422c3d30a121b1f6f939 Implement a simple and straightforward BTF sanity check when parsing BTF data. Right now it's very basic and just validates that all the string offsets and type IDs are within valid range. For FUNC we also check that it points to FUNC_PROTO kinds. Even with such simple checks it fixes a bunch of crashes found by OSS fuzzer ([0]-[5]) and will allow fuzzer to make further progress. Some other invariants will be checked in follow up patches (like ensuring there is no infinite type loops), but this seems like a good start already. Adding FUNC -> FUNC_PROTO check revealed that one of selftests has a problem with FUNC pointing to VAR instead, so fix it up in the same commit. [0] https://github.com/libbpf/libbpf/issues/482 [1] https://github.com/libbpf/libbpf/issues/483 [2] https://github.com/libbpf/libbpf/issues/485 [3] https://github.com/libbpf/libbpf/issues/613 [4] https://github.com/libbpf/libbpf/issues/618 [5] https://github.com/libbpf/libbpf/issues/619 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Song Liu <song@kernel.org> Closes: https://github.com/libbpf/libbpf/issues/617 Link: https://lore.kernel.org/bpf/20230825202152.1813394-1-andrii@kernel.org 
Implement a simple and straightforward BTF sanity check when parsing BTF
data. Right now it's very basic and just validates that all the string
offsets and type IDs are within valid range. For FUNC we also check that
it points to FUNC_PROTO kinds.

Even with such simple checks it fixes a bunch of crashes found by OSS
fuzzer ([0]-[5]) and will allow fuzzer to make further progress.

Some other invariants will be checked in follow up patches (like
ensuring there is no infinite type loops), but this seems like a good
start already.

Adding FUNC -> FUNC_PROTO check revealed that one of selftests has
a problem with FUNC pointing to VAR instead, so fix it up in the same
commit.

  [0] https://github.com/libbpf/libbpf/issues/482
  [1] https://github.com/libbpf/libbpf/issues/483
  [2] https://github.com/libbpf/libbpf/issues/485
  [3] https://github.com/libbpf/libbpf/issues/613
  [4] https://github.com/libbpf/libbpf/issues/618
  [5] https://github.com/libbpf/libbpf/issues/619

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Song Liu <song@kernel.org>
Closes: https://github.com/libbpf/libbpf/issues/617
Link: https://lore.kernel.org/bpf/20230825202152.1813394-1-andrii@kernel.org
libbpf: Ensure libbpf always opens files with O_CLOEXEC 2023-05-26T10:05:32+00:00 Andrii Nakryiko andrii@kernel.org 2023-05-25T22:13:10+00:00 59842c5451fe830737600276ba9dee4595341d77 Make sure that libbpf code always gets FD with O_CLOEXEC flag set, regardless if file is open through open() or fopen(). For the latter this means to add "e" to mode string, which is supported since pretty ancient glibc v2.7. Also drop the outdated TODO comment in usdt.c, which was already completed. Suggested-by: Lennart Poettering <lennart@poettering.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230525221311.2136408-1-andrii@kernel.org 
Make sure that libbpf code always gets FD with O_CLOEXEC flag set,
regardless if file is open through open() or fopen(). For the latter
this means to add "e" to mode string, which is supported since pretty
ancient glibc v2.7.

Also drop the outdated TODO comment in usdt.c, which was already completed.

Suggested-by: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230525221311.2136408-1-andrii@kernel.org
libbpf: Remove several dead assignments 2023-03-01T19:13:11+00:00 Viktor Malik vmalik@redhat.com 2023-03-01T08:53:54+00:00 7832d06bd9f9080d9ceae388bb81bf33adce3850 Clang Static Analyzer (scan-build) reports several dead assignments in libbpf where the assigned value is unconditionally overridden by another value before it is read. Remove these assignments. Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/5503d18966583e55158471ebbb2f67374b11bf5e.1677658777.git.vmalik@redhat.com 
Clang Static Analyzer (scan-build) reports several dead assignments in
libbpf where the assigned value is unconditionally overridden by another
value before it is read. Remove these assignments.

Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/5503d18966583e55158471ebbb2f67374b11bf5e.1677658777.git.vmalik@redhat.com
libbpf: Use bpf_{btf,link,map,prog}_get_info_by_fd() 2023-02-16T23:32:45+00:00 Ilya Leoshkevich iii@linux.ibm.com 2023-02-14T23:12:15+00:00 629dfc660cae86a6a48d19f5295226d03caae673 Use the new type-safe wrappers around bpf_obj_get_info_by_fd(). Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230214231221.249277-3-iii@linux.ibm.com 
Use the new type-safe wrappers around bpf_obj_get_info_by_fd().

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230214231221.249277-3-iii@linux.ibm.com
libbpf: Return -ENODATA for missing btf section 2023-01-03T22:27:42+00:00 Changbin Du changbin.du@gmail.com 2022-12-31T15:14:36+00:00 acd3b7768048fe338248cdf43ccfbf8c084a6bc1 As discussed before, return -ENODATA (No data available) would be more meaningful than ENOENT (No such file or directory). Suggested-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Changbin Du <changbin.du@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221231151436.6541-1-changbin.du@gmail.com 
As discussed before, return -ENODATA (No data available) would be more
meaningful than ENOENT (No such file or directory).

Suggested-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221231151436.6541-1-changbin.du@gmail.com