[PATCH bpf-next v13 4/8] bpf: Add syscall common attributes support for prog_load
From: Leon Hwang <hidden>
Date: 2026-05-11 15:29:46
Also in:
bpf, linux-kselftest, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
BPF_PROG_LOAD can now take log parameters from both union bpf_attr and struct bpf_common_attr. The merge rules are: - if both sides provide a complete log tuple (buf/size/level) and they match, use it; - if only one side provides log parameters, use that one; - if both sides provide complete tuples but they differ, return -EINVAL. Signed-off-by: Leon Hwang <redacted> --- include/linux/bpf_verifier.h | 3 ++- kernel/bpf/log.c | 34 +++++++++++++++++++++++++++------- kernel/bpf/syscall.c | 3 ++- 3 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 8d27ad1f9f94..8433430dedb7 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h@@ -764,7 +764,8 @@ struct bpf_log_attr { }; int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level, - u32 offsetof_log_true_size, bpfptr_t uattr); + u32 offsetof_log_true_size, bpfptr_t uattr, struct bpf_common_attr *common, + bpfptr_t uattr_common, u32 size_common); int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log); #define BPF_MAX_SUBPROGS 256
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index 1b1efe75398b..fd12ad5a0338 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c@@ -13,17 +13,17 @@ #define verbose(env, fmt, args...) bpf_verifier_log_write(env, fmt, ##args) -static bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log) +static bool bpf_verifier_log_attr_valid(u32 log_level, char __user *log_buf, u32 log_size) { /* ubuf and len_total should both be specified (or not) together */ - if (!!log->ubuf != !!log->len_total) + if (!!log_buf != !!log_size) return false; /* log buf without log_level is meaningless */ - if (log->ubuf && log->level == 0) + if (log_buf && log_level == 0) return false; - if (log->level & ~BPF_LOG_MASK) + if (log_level & ~BPF_LOG_MASK) return false; - if (log->len_total > UINT_MAX >> 2) + if (log_size > UINT_MAX >> 2) return false; return true; }
@@ -36,7 +36,7 @@ int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level, log->len_total = log_size; /* log attributes have to be sane */ - if (!bpf_verifier_log_attr_valid(log)) + if (!bpf_verifier_log_attr_valid(log_level, log_buf, log_size)) return -EINVAL; return 0;
@@ -827,16 +827,36 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st } int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level, - u32 offsetof_log_true_size, bpfptr_t uattr) + u32 offsetof_log_true_size, bpfptr_t uattr, struct bpf_common_attr *common, + bpfptr_t uattr_common, u32 size_common) { + char __user *ubuf_common = u64_to_user_ptr(common->log_buf); char __user *ubuf = u64_to_user_ptr(log_buf); + if (!bpf_verifier_log_attr_valid(common->log_level, ubuf_common, common->log_size) || + !bpf_verifier_log_attr_valid(log_level, ubuf, log_size)) + return -EINVAL; + + if (ubuf && ubuf_common && (ubuf != ubuf_common || log_size != common->log_size || + log_level != common->log_level)) + return -EINVAL; + memset(log, 0, sizeof(*log)); log->ubuf = ubuf; log->size = log_size; log->level = log_level; log->offsetof_true_size = offsetof_log_true_size; log->uattr = uattr; + + if (!ubuf && ubuf_common) { + log->ubuf = ubuf_common; + log->size = common->log_size; + log->level = common->log_level; + log->uattr = uattr_common; + log->offsetof_true_size = 0; + if (size_common >= offsetofend(struct bpf_common_attr, log_true_size)) + log->offsetof_true_size = offsetof(struct bpf_common_attr, log_true_size); + } return 0; }
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 70b78ddcdedb..db893cae826c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c@@ -6271,7 +6271,8 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size, if (size >= offsetofend(union bpf_attr, log_true_size)) offsetof_log_true_size = offsetof(union bpf_attr, log_true_size); err = bpf_log_attr_init(&attr_log, attr.log_buf, attr.log_size, attr.log_level, - offsetof_log_true_size, uattr); + offsetof_log_true_size, uattr, &attr_common, uattr_common, + size_common); err = err ?: bpf_prog_load(&attr, uattr, &attr_log); break; case BPF_OBJ_PIN:
--
2.54.0