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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
commit | 19f4f86bfed21c5326ed2acebe1163f3a83e832b (patch) | |
tree | d59b9989ce55ed23693e80974d94c856f1c2c8b1 /src/resolve/dns-type.c | |
parent | Initial commit. (diff) | |
download | systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.tar.xz systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.zip |
Adding upstream version 241.upstream/241upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/resolve/dns-type.c')
-rw-r--r-- | src/resolve/dns-type.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/src/resolve/dns-type.c b/src/resolve/dns-type.c new file mode 100644 index 0000000..c96f60a --- /dev/null +++ b/src/resolve/dns-type.c @@ -0,0 +1,316 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <sys/socket.h> +#include <errno.h> + +#include "dns-type.h" +#include "parse-util.h" +#include "string-util.h" + +typedef const struct { + uint16_t type; + const char *name; +} dns_type; + +static const struct dns_type_name * +lookup_dns_type (register const char *str, register GPERF_LEN_TYPE len); + +#include "dns_type-from-name.h" +#include "dns_type-to-name.h" + +int dns_type_from_string(const char *s) { + const struct dns_type_name *sc; + + assert(s); + + sc = lookup_dns_type(s, strlen(s)); + if (sc) + return sc->id; + + s = startswith_no_case(s, "TYPE"); + if (s) { + unsigned x; + + if (safe_atou(s, &x) >= 0 && + x <= UINT16_MAX) + return (int) x; + } + + return _DNS_TYPE_INVALID; +} + +bool dns_type_is_pseudo(uint16_t type) { + + /* Checks whether the specified type is a "pseudo-type". What + * a "pseudo-type" precisely is, is defined only very weakly, + * but apparently entails all RR types that are not actually + * stored as RRs on the server and should hence also not be + * cached. We use this list primarily to validate NSEC type + * bitfields, and to verify what to cache. */ + + return IN_SET(type, + 0, /* A Pseudo RR type, according to RFC 2931 */ + DNS_TYPE_ANY, + DNS_TYPE_AXFR, + DNS_TYPE_IXFR, + DNS_TYPE_OPT, + DNS_TYPE_TSIG, + DNS_TYPE_TKEY + ); +} + +bool dns_class_is_pseudo(uint16_t class) { + return class == DNS_TYPE_ANY; +} + +bool dns_type_is_valid_query(uint16_t type) { + + /* The types valid as questions in packets */ + + return !IN_SET(type, + 0, + DNS_TYPE_OPT, + DNS_TYPE_TSIG, + DNS_TYPE_TKEY, + + /* RRSIG are technically valid as questions, but we refuse doing explicit queries for them, as + * they aren't really payload, but signatures for payload, and cannot be validated on their + * own. After all they are the signatures, and have no signatures of their own validating + * them. */ + DNS_TYPE_RRSIG); +} + +bool dns_type_is_zone_transer(uint16_t type) { + + /* Zone transfers, either normal or incremental */ + + return IN_SET(type, + DNS_TYPE_AXFR, + DNS_TYPE_IXFR); +} + +bool dns_type_is_valid_rr(uint16_t type) { + + /* The types valid as RR in packets (but not necessarily + * stored on servers). */ + + return !IN_SET(type, + DNS_TYPE_ANY, + DNS_TYPE_AXFR, + DNS_TYPE_IXFR); +} + +bool dns_class_is_valid_rr(uint16_t class) { + return class != DNS_CLASS_ANY; +} + +bool dns_type_may_redirect(uint16_t type) { + /* The following record types should never be redirected using + * CNAME/DNAME RRs. See + * <https://tools.ietf.org/html/rfc4035#section-2.5>. */ + + if (dns_type_is_pseudo(type)) + return false; + + return !IN_SET(type, + DNS_TYPE_CNAME, + DNS_TYPE_DNAME, + DNS_TYPE_NSEC3, + DNS_TYPE_NSEC, + DNS_TYPE_RRSIG, + DNS_TYPE_NXT, + DNS_TYPE_SIG, + DNS_TYPE_KEY); +} + +bool dns_type_may_wildcard(uint16_t type) { + + /* The following records may not be expanded from wildcard RRsets */ + + if (dns_type_is_pseudo(type)) + return false; + + return !IN_SET(type, + DNS_TYPE_NSEC3, + DNS_TYPE_SOA, + + /* Prohibited by https://tools.ietf.org/html/rfc4592#section-4.4 */ + DNS_TYPE_DNAME); +} + +bool dns_type_apex_only(uint16_t type) { + + /* Returns true for all RR types that may only appear signed in a zone apex */ + + return IN_SET(type, + DNS_TYPE_SOA, + DNS_TYPE_NS, /* this one can appear elsewhere, too, but not signed */ + DNS_TYPE_DNSKEY, + DNS_TYPE_NSEC3PARAM); +} + +bool dns_type_is_dnssec(uint16_t type) { + return IN_SET(type, + DNS_TYPE_DS, + DNS_TYPE_DNSKEY, + DNS_TYPE_RRSIG, + DNS_TYPE_NSEC, + DNS_TYPE_NSEC3, + DNS_TYPE_NSEC3PARAM); +} + +bool dns_type_is_obsolete(uint16_t type) { + return IN_SET(type, + /* Obsoleted by RFC 973 */ + DNS_TYPE_MD, + DNS_TYPE_MF, + DNS_TYPE_MAILA, + + /* Kinda obsoleted by RFC 2505 */ + DNS_TYPE_MB, + DNS_TYPE_MG, + DNS_TYPE_MR, + DNS_TYPE_MINFO, + DNS_TYPE_MAILB, + + /* RFC1127 kinda obsoleted this by recommending against its use */ + DNS_TYPE_WKS, + + /* Declared historical by RFC 6563 */ + DNS_TYPE_A6, + + /* Obsoleted by DNSSEC-bis */ + DNS_TYPE_NXT, + + /* RFC 1035 removed support for concepts that needed this from RFC 883 */ + DNS_TYPE_NULL); +} + +bool dns_type_needs_authentication(uint16_t type) { + + /* Returns true for all (non-obsolete) RR types where records are not useful if they aren't + * authenticated. I.e. everything that contains crypto keys. */ + + return IN_SET(type, + DNS_TYPE_CERT, + DNS_TYPE_SSHFP, + DNS_TYPE_IPSECKEY, + DNS_TYPE_DS, + DNS_TYPE_DNSKEY, + DNS_TYPE_TLSA, + DNS_TYPE_CDNSKEY, + DNS_TYPE_OPENPGPKEY, + DNS_TYPE_CAA); +} + +int dns_type_to_af(uint16_t t) { + switch (t) { + + case DNS_TYPE_A: + return AF_INET; + + case DNS_TYPE_AAAA: + return AF_INET6; + + case DNS_TYPE_ANY: + return AF_UNSPEC; + + default: + return -EINVAL; + } +} + +const char *dns_class_to_string(uint16_t class) { + + switch (class) { + + case DNS_CLASS_IN: + return "IN"; + + case DNS_CLASS_ANY: + return "ANY"; + } + + return NULL; +} + +int dns_class_from_string(const char *s) { + + if (!s) + return _DNS_CLASS_INVALID; + + if (strcaseeq(s, "IN")) + return DNS_CLASS_IN; + else if (strcaseeq(s, "ANY")) + return DNS_CLASS_ANY; + + return _DNS_CLASS_INVALID; +} + +const char* tlsa_cert_usage_to_string(uint8_t cert_usage) { + + switch (cert_usage) { + + case 0: + return "CA constraint"; + + case 1: + return "Service certificate constraint"; + + case 2: + return "Trust anchor assertion"; + + case 3: + return "Domain-issued certificate"; + + case 4 ... 254: + return "Unassigned"; + + case 255: + return "Private use"; + } + + return NULL; /* clang cannot count that we covered everything */ +} + +const char* tlsa_selector_to_string(uint8_t selector) { + switch (selector) { + + case 0: + return "Full Certificate"; + + case 1: + return "SubjectPublicKeyInfo"; + + case 2 ... 254: + return "Unassigned"; + + case 255: + return "Private use"; + } + + return NULL; +} + +const char* tlsa_matching_type_to_string(uint8_t selector) { + + switch (selector) { + + case 0: + return "No hash used"; + + case 1: + return "SHA-256"; + + case 2: + return "SHA-512"; + + case 3 ... 254: + return "Unassigned"; + + case 255: + return "Private use"; + } + + return NULL; +} |