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bpf: Remove struct bpf_verifier_env argument from print_bpf_insn

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We use print_bpf_insn in user space (bpftool and soon perf),
so it'd be nice to keep it generic and strip it off the kernel
struct bpf_verifier_env argument.

This argument can be safely removed, because its users can
use the struct bpf_insn_cbs::private_data to pass it.

By changing the argument type  we can no longer have clean
'verbose' alias to 'bpf_verifier_log_write' in verifier.c.
Instead  we're adding the  'verbose' cb_print callback and
removing the alias.

This way we have new cb_print callback in place, and all
the 'verbose(env, ...) calls in verifier.c will cleanly
cast to 'verbose(void *, ...)' so no other change is
needed.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jiri Olsa
2018-03-23 11:41:28 +01:00
committed by Daniel Borkmann
parent ae06c70b13
commit abe0884011
3 changed files with 54 additions and 47 deletions
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44
kernel/bpf/verifier.c
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@@ -168,23 +168,16 @@ struct bpf_call_arg_meta {
static DEFINE_MUTEX(bpf_verifier_lock);
/* log_level controls verbosity level of eBPF verifier.
* bpf_verifier_log_write() is used to dump the verification trace to the log,
* so the user can figure out what's wrong with the program
*/
__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
const char *fmt, ...)
static void log_write(struct bpf_verifier_env *env, const char *fmt,
va_list args)
{
struct bpf_verifer_log *log = &env->log;
unsigned int n;
va_list args;
if (!log->level || !log->ubuf || bpf_verifier_log_full(log))
return;
va_start(args, fmt);
n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args);
va_end(args);
WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1,
"verifier log line truncated - local buffer too short\n");
@@ -197,14 +190,30 @@ __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
else
log->ubuf = NULL;
}
EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
/* Historically bpf_verifier_log_write was called verbose, but the name was too
* generic for symbol export. The function was renamed, but not the calls in
* the verifier to avoid complicating backports. Hence the alias below.
/* log_level controls verbosity level of eBPF verifier.
* bpf_verifier_log_write() is used to dump the verification trace to the log,
* so the user can figure out what's wrong with the program
*/
static __printf(2, 3) void verbose(struct bpf_verifier_env *env,
const char *fmt, ...)
__attribute__((alias("bpf_verifier_log_write")));
__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
log_write(env, fmt, args);
va_end(args);
}
EXPORT_SYMBOL_GPL(bpf_verifier_log_write);
__printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
log_write(private_data, fmt, args);
va_end(args);
}
static bool type_is_pkt_pointer(enum bpf_reg_type type)
{
@@ -4600,10 +4609,11 @@ static int do_check(struct bpf_verifier_env *env)
if (env->log.level) {
const struct bpf_insn_cbs cbs = {
.cb_print = verbose,
.private_data = env,
};
verbose(env, "%d: ", insn_idx);
print_bpf_insn(&cbs, env, insn, env->allow_ptr_leaks);
print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
}
if (bpf_prog_is_dev_bound(env->prog->aux)) {