The next commit will add support for reporting logs via extended common attributes, including 'log_true_size'.
To prepare for that, refactor the 'log_true_size' reporting logic by introducing a new struct bpf_log_attr to encapsulate log-related behavior: * bpf_prog_load_log_attr_init(): initialize the log fields, which will support extended common attributes in the next commit. * bpf_log_attr_finalize(): handle log finalization and write back 'log_true_size' to userspace. Signed-off-by: Leon Hwang <[email protected]> --- include/linux/bpf.h | 19 ++++++++++++++++- include/linux/bpf_verifier.h | 11 ++++++++++ kernel/bpf/log.c | 40 ++++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 9 +++++++- kernel/bpf/verifier.c | 19 ++++++----------- 5 files changed, 83 insertions(+), 15 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 5936f8e2996f..3a525a7e8747 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2867,8 +2867,25 @@ int bpf_get_file_flag(int flags); int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size, size_t actual_size); +struct bpf_attrs { + const void *attr; + bpfptr_t uattr; + u32 size; +}; + +static inline void bpf_attrs_init(struct bpf_attrs *attrs, const void *attr, bpfptr_t uattr, + u32 size) +{ + memset(attrs, 0, sizeof(*attrs)); + attrs->attr = attr; + attrs->uattr = uattr; + attrs->size = size; +} + /* verify correctness of eBPF program */ -int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size); +struct bpf_log_attr; +int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, + struct bpf_log_attr *log_attr); #ifndef CONFIG_BPF_JIT_ALWAYS_ON void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth); diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 130bcbd66f60..4c9632c40059 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -631,6 +631,17 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) return log && log->level; } +struct bpf_log_attr { + u64 log_buf; + u32 log_size; + u32 log_level; + struct bpf_attrs *attrs; + u32 offsetof_log_true_size; +}; + +int bpf_prog_load_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs *attrs); +int bpf_log_attr_finalize(struct bpf_log_attr *log_attr, struct bpf_verifier_log *log); + #define BPF_MAX_SUBPROGS 256 struct bpf_subprog_arg_info { diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index a0c3b35de2ce..457b724c4176 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -863,3 +863,43 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st } print_verifier_state(env, vstate, frameno, false); } + +static int bpf_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs *attrs, u64 log_buf, + u32 log_size, u32 log_level, int offsetof_log_true_size) +{ + memset(log_attr, 0, sizeof(*log_attr)); + log_attr->log_buf = log_buf; + log_attr->log_size = log_size; + log_attr->log_level = log_level; + log_attr->attrs = attrs; + log_attr->offsetof_log_true_size = offsetof_log_true_size; + return 0; +} + +int bpf_prog_load_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs *attrs) +{ + const union bpf_attr *attr = attrs->attr; + + return bpf_log_attr_init(log_attr, attrs, attr->log_buf, attr->log_size, attr->log_level, + offsetof(union bpf_attr, log_true_size)); +} + +int bpf_log_attr_finalize(struct bpf_log_attr *log_attr, struct bpf_verifier_log *log) +{ + u32 log_true_size, off; + size_t size; + int err; + + if (!log) + return 0; + + err = bpf_vlog_finalize(log, &log_true_size); + + size = sizeof(log_true_size); + off = log_attr->offsetof_log_true_size; + if (log_attr->attrs && log_attr->attrs->size >= off + size && + copy_to_bpfptr_offset(log_attr->attrs->uattr, off, &log_true_size, size)) + err = -EFAULT; + + return err; +} diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index af703f7ea58e..0b389bc6add8 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2871,6 +2871,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) struct bpf_prog *prog, *dst_prog = NULL; struct btf *attach_btf = NULL; struct bpf_token *token = NULL; + struct bpf_log_attr log_attr; + struct bpf_attrs attrs; bool bpf_cap; int err; char license[128]; @@ -3082,8 +3084,13 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) if (err) goto free_prog_sec; + bpf_attrs_init(&attrs, attr, uattr, uattr_size); + err = bpf_prog_load_log_attr_init(&log_attr, &attrs); + if (err < 0) + goto free_used_maps; + /* run eBPF verifier */ - err = bpf_check(&prog, attr, uattr, uattr_size); + err = bpf_check(&prog, attr, uattr, &log_attr); if (err < 0) goto free_used_maps; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 53635ea2e41b..921a7b6a6686 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -25106,12 +25106,12 @@ static int compute_scc(struct bpf_verifier_env *env) return err; } -int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size) +int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, + struct bpf_log_attr *log_attr) { u64 start_time = ktime_get_ns(); struct bpf_verifier_env *env; int i, len, ret = -EINVAL, err; - u32 log_true_size; bool is_priv; BTF_TYPE_EMIT(enum bpf_features); @@ -25158,9 +25158,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 /* user could have requested verbose verifier output * and supplied buffer to store the verification trace */ - ret = bpf_vlog_init(&env->log, attr->log_level, - (char __user *) (unsigned long) attr->log_buf, - attr->log_size); + ret = bpf_vlog_init(&env->log, log_attr->log_level, + u64_to_user_ptr(log_attr->log_buf), + log_attr->log_size); if (ret) goto err_unlock; @@ -25310,17 +25310,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 env->prog->aux->verified_insns = env->insn_processed; /* preserve original error even if log finalization is successful */ - err = bpf_vlog_finalize(&env->log, &log_true_size); + err = bpf_log_attr_finalize(log_attr, &env->log); if (err) ret = err; - if (uattr_size >= offsetofend(union bpf_attr, log_true_size) && - copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size), - &log_true_size, sizeof(log_true_size))) { - ret = -EFAULT; - goto err_release_maps; - } - if (ret) goto err_release_maps; -- 2.52.0
