From 430e68d10baf55e4c40d4dd1de8201c1caf5dddd Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Wed, 10 Jan 2018 12:26:06 +0000 Subject: bpf: export function to write into verifier log buffer Rename the BPF verifier `verbose()` to `bpf_verifier_log_write()` and export it, so that other components (in particular, drivers for BPF offload) can reuse the user buffer log to dump error messages at verification time. Renaming `verbose()` was necessary in order to avoid a name so generic to be exported to the global namespace. However to prevent too much pain for backports, the calls to `verbose()` in the kernel BPF verifier were not changed. Instead, use function aliasing to make `verbose` point to `bpf_verifier_log_write`. Another solution could consist in making a wrapper around `verbose()`, but since it is a variadic function, I don't see a clean way without creating two identical wrappers, one for the verifier and one to export. Signed-off-by: Quentin Monnet Reviewed-by: Jakub Kicinski Signed-off-by: Daniel Borkmann --- kernel/bpf/verifier.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d921ab387b0b..3b2b47666180 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -169,11 +169,11 @@ struct bpf_call_arg_meta { static DEFINE_MUTEX(bpf_verifier_lock); /* log_level controls verbosity level of eBPF verifier. - * verbose() is used to dump the verification trace to the log, so the user - * can figure out what's wrong with the program + * 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, ...) +__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, + const char *fmt, ...) { struct bpf_verifer_log *log = &env->log; unsigned int n; @@ -197,6 +197,14 @@ static __printf(2, 3) void verbose(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. + */ +static __printf(2, 3) void verbose(struct bpf_verifier_env *env, + const char *fmt, ...) + __attribute__((alias("bpf_verifier_log_write"))); static bool type_is_pkt_pointer(enum bpf_reg_type type) { -- cgit v1.2.3-55-g7522