7470cc4c73
https://tools.ietf.org/html/rfc1035#section-2.3.1 says (approximately) that only letters, numbers, and non-leading non-trailing dashes are allowed (for entries with A/AAAA records). We set no restrictions. hosts(5) says: > Host names may contain only alphanumeric characters, minus signs ("-"), and > periods ("."). They must begin with an alphabetic character and end with an > alphanumeric character. nss-files follows those rules, and will ignore names in /etc/hosts that do not follow this rule. Let's follow the documented rules for /etc/hosts. In particular, this makes us consitent with nss-files, reducing surprises for the user. I'm pretty sure we should apply stricter filtering to names received over DNS and LLMNR and MDNS, but it's a bigger project, because the rules differ depepending on which level the label appears (rules for top-level names are stricter), and this patch takes the minimalistic approach and only changes behaviour for /etc/hosts. Escape syntax is also disallowed in /etc/hosts, even if the resulting character would be allowed. Other tools that parse /etc/hosts do not support this, and there is no need to use it because no allowed characters benefit from escaping.
193 lines
4.7 KiB
C
193 lines
4.7 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include "alloc-util.h"
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#include "dns-domain.h"
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#include "resolved-dns-search-domain.h"
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int dns_search_domain_new(
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Manager *m,
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DnsSearchDomain **ret,
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DnsSearchDomainType type,
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Link *l,
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const char *name) {
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_cleanup_free_ char *normalized = NULL;
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DnsSearchDomain *d;
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int r;
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assert(m);
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assert((type == DNS_SEARCH_DOMAIN_LINK) == !!l);
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assert(name);
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r = dns_name_normalize(name, 0, &normalized);
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if (r < 0)
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return r;
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if (l) {
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if (l->n_search_domains >= LINK_SEARCH_DOMAINS_MAX)
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return -E2BIG;
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} else {
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if (m->n_search_domains >= MANAGER_SEARCH_DOMAINS_MAX)
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return -E2BIG;
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}
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d = new0(DnsSearchDomain, 1);
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if (!d)
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return -ENOMEM;
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d->n_ref = 1;
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d->manager = m;
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d->type = type;
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d->name = TAKE_PTR(normalized);
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switch (type) {
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case DNS_SEARCH_DOMAIN_LINK:
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d->link = l;
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LIST_APPEND(domains, l->search_domains, d);
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l->n_search_domains++;
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break;
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case DNS_SERVER_SYSTEM:
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LIST_APPEND(domains, m->search_domains, d);
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m->n_search_domains++;
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break;
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default:
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assert_not_reached("Unknown search domain type");
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}
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d->linked = true;
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if (ret)
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*ret = d;
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return 0;
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}
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static DnsSearchDomain* dns_search_domain_free(DnsSearchDomain *d) {
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assert(d);
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free(d->name);
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return mfree(d);
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}
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DEFINE_TRIVIAL_REF_UNREF_FUNC(DnsSearchDomain, dns_search_domain, dns_search_domain_free);
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void dns_search_domain_unlink(DnsSearchDomain *d) {
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assert(d);
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assert(d->manager);
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if (!d->linked)
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return;
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switch (d->type) {
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case DNS_SEARCH_DOMAIN_LINK:
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assert(d->link);
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assert(d->link->n_search_domains > 0);
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LIST_REMOVE(domains, d->link->search_domains, d);
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d->link->n_search_domains--;
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break;
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case DNS_SEARCH_DOMAIN_SYSTEM:
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assert(d->manager->n_search_domains > 0);
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LIST_REMOVE(domains, d->manager->search_domains, d);
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d->manager->n_search_domains--;
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break;
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}
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d->linked = false;
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dns_search_domain_unref(d);
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}
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void dns_search_domain_move_back_and_unmark(DnsSearchDomain *d) {
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DnsSearchDomain *tail;
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assert(d);
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if (!d->marked)
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return;
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d->marked = false;
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if (!d->linked || !d->domains_next)
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return;
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switch (d->type) {
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case DNS_SEARCH_DOMAIN_LINK:
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assert(d->link);
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LIST_FIND_TAIL(domains, d, tail);
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LIST_REMOVE(domains, d->link->search_domains, d);
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LIST_INSERT_AFTER(domains, d->link->search_domains, tail, d);
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break;
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case DNS_SEARCH_DOMAIN_SYSTEM:
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LIST_FIND_TAIL(domains, d, tail);
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LIST_REMOVE(domains, d->manager->search_domains, d);
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LIST_INSERT_AFTER(domains, d->manager->search_domains, tail, d);
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break;
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default:
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assert_not_reached("Unknown search domain type");
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}
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}
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void dns_search_domain_unlink_all(DnsSearchDomain *first) {
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DnsSearchDomain *next;
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if (!first)
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return;
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next = first->domains_next;
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dns_search_domain_unlink(first);
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dns_search_domain_unlink_all(next);
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}
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void dns_search_domain_unlink_marked(DnsSearchDomain *first) {
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DnsSearchDomain *next;
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if (!first)
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return;
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next = first->domains_next;
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if (first->marked)
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dns_search_domain_unlink(first);
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dns_search_domain_unlink_marked(next);
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}
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void dns_search_domain_mark_all(DnsSearchDomain *first) {
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if (!first)
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return;
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first->marked = true;
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dns_search_domain_mark_all(first->domains_next);
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}
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int dns_search_domain_find(DnsSearchDomain *first, const char *name, DnsSearchDomain **ret) {
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DnsSearchDomain *d;
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int r;
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assert(name);
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assert(ret);
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LIST_FOREACH(domains, d, first) {
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r = dns_name_equal(name, d->name);
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if (r < 0)
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return r;
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if (r > 0) {
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*ret = d;
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return 1;
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}
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}
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*ret = NULL;
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return 0;
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}
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