bpf: Split off basic BPF verifier log into separate file

kernel/bpf/verifier.c file is large and growing larger all the time. So
it's good to start splitting off more or less self-contained parts into
separate files to keep source code size (somewhat) somewhat under
control.

This patch is a one step in this direction, moving some of BPF verifier log
routines into a separate kernel/bpf/log.c. Right now it's most low-level
and isolated routines to append data to log, reset log to previous
position, etc. Eventually we could probably move verifier state
printing logic here as well, but this patch doesn't attempt to do that
yet.

Subsequent patches will add more logic to verifier log management, so
having basics in a separate file will make sure verifier.c doesn't grow
more with new 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/20230406234205.323208-2-andrii@kernel.org

1 files changed, 7 insertions, 12 deletions

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 81d525d057c7..83dff25545ee 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -498,11 +498,6 @@ struct bpf_verifier_log {
 	u32 len_total;
 };
 
-static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log)
-{
-	return log->len_used >= log->len_total - 1;
-}
-
 #define BPF_LOG_LEVEL1	1
 #define BPF_LOG_LEVEL2	2
 #define BPF_LOG_STATS	4
@@ -512,6 +507,11 @@ static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log)
 #define BPF_LOG_MIN_ALIGNMENT 8U
 #define BPF_LOG_ALIGNMENT 40U
 
+static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log)
+{
+	return log->len_used >= log->len_total - 1;
+}
+
 static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
 {
 	return log &&
@@ -519,13 +519,6 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
 		 log->level == BPF_LOG_KERNEL);
 }
 
-static inline bool
-bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log)
-{
-	return log->len_total >= 128 && log->len_total <= UINT_MAX >> 2 &&
-	       log->level && log->ubuf && !(log->level & ~BPF_LOG_MASK);
-}
-
 #define BPF_MAX_SUBPROGS 256
 
 struct bpf_subprog_info {
@@ -608,12 +601,14 @@ struct bpf_verifier_env {
 	char type_str_buf[TYPE_STR_BUF_LEN];
 };
 
+bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log);
 __printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,
 				      const char *fmt, va_list args);
 __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
 					   const char *fmt, ...);
 __printf(2, 3) void bpf_log(struct bpf_verifier_log *log,
 			    const char *fmt, ...);
+void bpf_vlog_reset(struct bpf_verifier_log *log, u32 new_pos);
 
 static inline struct bpf_func_state *cur_func(struct bpf_verifier_env *env)
 {