diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2023-04-07 02:41:58 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2023-04-11 19:05:43 +0300 |
| commit | 47a71c1f9af0a334c9dfa97633c41de4feda4287 (patch) | |
| tree | 629b75bb5746fcdf557efc96777cb921ee1dcbbd /kernel/bpf/verifier.c | |
| parent | fa1c7d5cc404ac3b6e6b4ab6d00b07c76bd819be (diff) | |
| download | linux-47a71c1f9af0a334c9dfa97633c41de4feda4287.tar.xz | |
bpf: Add log_true_size output field to return necessary log buffer size
Add output-only log_true_size and btf_log_true_size field to
BPF_PROG_LOAD and BPF_BTF_LOAD commands, respectively. It will return
the size of log buffer necessary to fit in all the log contents at
specified log_level. This is very useful for BPF loader libraries like
libbpf to be able to size log buffer correctly, but could be used by
users directly, if necessary, as well.
This patch plumbs all this through the code, taking into account actual
bpf_attr size provided by user to determine if these new fields are
expected by users. And if they are, set them from kernel on return.
We refactory btf_parse() function to accommodate this, moving attr and
uattr handling inside it. The rest is very straightforward code, which
is split from the logging accounting changes in the previous patch to
make it simpler to review logic vs UAPI changes.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/bpf/20230406234205.323208-13-andrii@kernel.org
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a98cbc046d1e..308e7abeb979 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -18694,7 +18694,7 @@ struct btf *bpf_get_btf_vmlinux(void) return btf_vmlinux; } -int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr) +int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size) { u64 start_time = ktime_get_ns(); struct bpf_verifier_env *env; @@ -18861,6 +18861,12 @@ skip_full_check: env->prog->aux->verified_insns = env->insn_processed; bpf_vlog_finalize(log); + if (uattr_size >= offsetofend(union bpf_attr, log_true_size) && + copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size), + &log->len_max, sizeof(log->len_max))) { + ret = -EFAULT; + goto err_release_maps; + } if (bpf_vlog_truncated(log)) ret = -ENOSPC; if (log->level && log->level != BPF_LOG_KERNEL && !log->ubuf) |