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_log_attr_init(): initialize 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 | 4 +++- include/linux/bpf_verifier.h | 11 +++++++++++ kernel/bpf/log.c | 25 +++++++++++++++++++++++++ kernel/bpf/syscall.c | 13 ++++++++++--- kernel/bpf/verifier.c | 17 ++++------------- 5 files changed, 53 insertions(+), 17 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index cd9b96434904..d4dbcc7ad156 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2913,7 +2913,9 @@ int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size, size_t actual_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 *attr_log); #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 ef8e45a362d9..dbd9bdb955b3 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -635,6 +635,17 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) return log && log->level; } +struct bpf_log_attr { + char __user *log_buf; + u32 log_size; + u32 log_level; + u32 __user *log_true_size; +}; + +int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level, + u32 __user *log_true_size); +int bpf_log_attr_finalize(struct bpf_log_attr *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..e31747b84fe2 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -863,3 +863,28 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st } print_verifier_state(env, vstate, frameno, false); } + +int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level, + u32 __user *log_true_size) +{ + memset(log, 0, sizeof(*log)); + log->log_buf = u64_to_user_ptr(log_buf); + log->log_size = log_size; + log->log_level = log_level; + log->log_true_size = log_true_size; + return 0; +} + +int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log) +{ + u32 log_true_size; + int err; + + err = bpf_vlog_finalize(log, &log_true_size); + + if (attr->log_true_size && copy_to_user(attr->log_true_size, &log_true_size, + sizeof(log_true_size))) + return -EFAULT; + + return err; +} diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0e231c0b1d04..e86674811996 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2867,7 +2867,7 @@ static int bpf_prog_mark_insn_arrays_ready(struct bpf_prog *prog) /* last field in 'union bpf_attr' used by this command */ #define BPF_PROG_LOAD_LAST_FIELD keyring_id -static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) +static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log) { enum bpf_prog_type type = attr->prog_type; struct bpf_prog *prog, *dst_prog = NULL; @@ -3085,7 +3085,7 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) goto free_prog_sec; /* run eBPF verifier */ - err = bpf_check(&prog, attr, uattr, uattr_size); + err = bpf_check(&prog, attr, uattr, attr_log); if (err < 0) goto free_used_maps; @@ -6189,7 +6189,10 @@ static int prog_assoc_struct_ops(union bpf_attr *attr) static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size, bpfptr_t uattr_common, unsigned int size_common) { + bool from_user = !bpfptr_is_kernel(uattr); struct bpf_common_attr attr_common; + u32 __user *log_true_size = NULL; + struct bpf_log_attr attr_log; union bpf_attr attr; int err; @@ -6241,7 +6244,11 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size, err = map_freeze(&attr); break; case BPF_PROG_LOAD: - err = bpf_prog_load(&attr, uattr, size); + if (from_user && size >= offsetofend(union bpf_attr, log_true_size)) + log_true_size = uattr.user + offsetof(union bpf_attr, log_true_size); + err = bpf_log_attr_init(&attr_log, attr.log_buf, attr.log_size, attr.log_level, + log_true_size); + err = err ?: bpf_prog_load(&attr, uattr, &attr_log); break; case BPF_OBJ_PIN: err = bpf_obj_pin(&attr); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index edf5342b982f..f1447b1878fd 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -25840,12 +25840,12 @@ 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 *attr_log) { 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); @@ -25892,9 +25892,7 @@ 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, attr_log->log_level, attr_log->log_buf, attr_log->log_size); if (ret) goto err_unlock; @@ -26044,17 +26042,10 @@ 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(attr_log, &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
