Commit fd5fd538 authored by Anton Protopopov's avatar Anton Protopopov Committed by Andrii Nakryiko
Browse files

libbpf: Use proper errno value in nlattr 



Return value of the validate_nla() function can be propagated all the
way up to users of libbpf API. In case of error this libbpf version
of validate_nla returns -1 which will be seen as -EPERM from user's
point of view. Instead, return a more reasonable -EINVAL.

Fixes: bbf48c18 ("libbpf: add error reporting in XDP")
Suggested-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAnton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250510182011.2246631-1-a.s.protopopov@gmail.com
parent 3a320ed3

tools/lib/bpf/nlattr.c

+7 −8
Original line number Diff line number Diff line
@@ -63,16 +63,16 @@ static int validate_nla(struct nlattr *nla, int maxtype, 
		minlen = nla_attr_minlen[pt->type];



	if (libbpf_nla_len(nla) < minlen)

		return -1;

		return -EINVAL;



	if (pt->maxlen && libbpf_nla_len(nla) > pt->maxlen)

		return -1;

		return -EINVAL;



	if (pt->type == LIBBPF_NLA_STRING) {

		char *data = libbpf_nla_data(nla);



		if (data[libbpf_nla_len(nla) - 1] != '\0')

			return -1;

			return -EINVAL;

	}



	return 0;
@@ -118,19 +118,18 @@ int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, 
		if (policy) {

			err = validate_nla(nla, maxtype, policy);

			if (err < 0)

				goto errout;

				return err;

		}



		if (tb[type])

		if (tb[type]) {

			pr_warn("Attribute of type %#x found multiple times in message, "

				"previous attribute is being ignored.\n", type);

		}



		tb[type] = nla;

	}



	err = 0;

errout:

	return err;

	return 0;

}



/**