Commit 80b2b5c3 authored by Andrei Matei's avatar Andrei Matei Committed by Andrii Nakryiko
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libbpf: Fail early when loading programs with unspecified type 



Before this patch, a program with unspecified type
(BPF_PROG_TYPE_UNSPEC) would be passed to the BPF syscall, only to have
the kernel reject it with an opaque invalid argument error. This patch
makes libbpf reject such programs with a nicer error message - in
particular libbpf now tries to diagnose bad ELF section names at both
open time and load time.

Signed-off-by: default avatarAndrei Matei <andreimatei1@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201203043410.59699-1-andreimatei1@gmail.com
parent a8b415c9

tools/lib/bpf/libbpf.c

+14 −1
Original line number Diff line number Diff line
@@ -6629,6 +6629,16 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, 
	char *log_buf = NULL;

	int btf_fd, ret;



	if (prog->type == BPF_PROG_TYPE_UNSPEC) {

		/*

		 * The program type must be set.  Most likely we couldn't find a proper

		 * section definition at load time, and thus we didn't infer the type.

		 */

		pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n",

			prog->name, prog->sec_name);

		return -EINVAL;

	}



	if (!insns || !insns_cnt)

		return -EINVAL;
@@ -6920,9 +6930,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, 


	bpf_object__for_each_program(prog, obj) {

		prog->sec_def = find_sec_def(prog->sec_name);

		if (!prog->sec_def)

		if (!prog->sec_def) {

			/* couldn't guess, but user might manually specify */

			pr_debug("prog '%s': unrecognized ELF section name '%s'\n",

				prog->name, prog->sec_name);

			continue;

		}



		if (prog->sec_def->is_sleepable)

			prog->prog_flags |= BPF_F_SLEEPABLE;