diff options
Diffstat (limited to 'debian/patches/0035-CVE-2021-25220.patch')
| -rw-r--r-- | debian/patches/0035-CVE-2021-25220.patch | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/debian/patches/0035-CVE-2021-25220.patch b/debian/patches/0035-CVE-2021-25220.patch new file mode 100644 index 0000000..48652e1 --- /dev/null +++ b/debian/patches/0035-CVE-2021-25220.patch @@ -0,0 +1,203 @@ +From: Debian DNS Team <team+dns@tracker.debian.org> +Date: Mon, 14 Mar 2022 15:31:10 +0100 +Subject: CVE-2021-25220 + +--- + lib/dns/resolver.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++--- + 1 file changed, 120 insertions(+), 5 deletions(-) + +diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c +index bfc1ae2..cabcbdc 100644 +--- a/lib/dns/resolver.c ++++ b/lib/dns/resolver.c +@@ -68,6 +68,7 @@ + #include <dns/stats.h> + #include <dns/tsig.h> + #include <dns/validator.h> ++#include <dns/zone.h> + + #ifdef WANT_QUERYTRACE + #define RTRACE(m) isc_log_write(dns_lctx, \ +@@ -314,6 +315,8 @@ struct fetchctx { + bool ns_ttl_ok; + uint32_t ns_ttl; + isc_counter_t * qc; ++ dns_fixedname_t fwdfname; ++ dns_name_t *fwdname; + + /*% + * The number of events we're waiting for. +@@ -3304,6 +3307,7 @@ fctx_getaddresses(fetchctx_t *fctx, bool badcache) { + if (result == ISC_R_SUCCESS) { + fwd = ISC_LIST_HEAD(forwarders->fwdrs); + fctx->fwdpolicy = forwarders->fwdpolicy; ++ dns_name_copy(domain, fctx->fwdname, NULL); + if (fctx->fwdpolicy == dns_fwdpolicy_only && + isstrictsubdomain(domain, &fctx->domain)) { + fcount_decr(fctx); +@@ -4334,6 +4338,9 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type, + fctx->restarts = 0; + fctx->querysent = 0; + fctx->referrals = 0; ++ ++ fctx->fwdname = dns_fixedname_initname(&fctx->fwdfname); ++ + TIME_NOW(&fctx->start); + fctx->timeouts = 0; + fctx->lamecount = 0; +@@ -4386,8 +4393,10 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type, + domain = dns_fixedname_initname(&fixed); + result = dns_fwdtable_find2(fctx->res->view->fwdtable, fwdname, + domain, &forwarders); +- if (result == ISC_R_SUCCESS) ++ if (result == ISC_R_SUCCESS) { + fctx->fwdpolicy = forwarders->fwdpolicy; ++ dns_name_copy(domain, fctx->fwdname, NULL); ++ } + + if (fctx->fwdpolicy != dns_fwdpolicy_only) { + /* +@@ -6144,6 +6153,107 @@ mark_related(dns_name_t *name, dns_rdataset_t *rdataset, + rdataset->attributes |= DNS_RDATASETATTR_EXTERNAL; + } + ++/* ++ * Returns true if 'name' is external to the namespace for which ++ * the server being queried can answer, either because it's not a ++ * subdomain or because it's below a forward declaration or a ++ * locally served zone. ++ */ ++static inline bool ++name_external(dns_name_t *name, dns_rdatatype_t type, fetchctx_t *fctx) { ++ isc_result_t result; ++ dns_forwarders_t *forwarders = NULL; ++ dns_fixedname_t fixed, zfixed; ++ dns_name_t *fname = dns_fixedname_initname(&fixed); ++ dns_name_t *zfname = dns_fixedname_initname(&zfixed); ++ dns_name_t *apex = NULL; ++ dns_name_t suffix; ++ dns_zone_t *zone = NULL; ++ unsigned int labels; ++ dns_namereln_t rel; ++ ++ apex = ISFORWARDER(fctx->addrinfo) ? fctx->fwdname : &fctx->domain; ++ ++ /* ++ * The name is outside the queried namespace. ++ */ ++ rel = dns_name_fullcompare(name, apex, &(int){ 0 }, ++ &(unsigned int){ 0U }); ++ if (rel != dns_namereln_subdomain && rel != dns_namereln_equal) { ++ return (true); ++ } ++ ++ /* ++ * If the record lives in the parent zone, adjust the name so we ++ * look for the correct zone or forward clause. ++ */ ++ labels = dns_name_countlabels(name); ++ if (dns_rdatatype_atparent(type) && labels > 1U) { ++ dns_name_init(&suffix, NULL); ++ dns_name_getlabelsequence(name, 1, labels - 1, &suffix); ++ name = &suffix; ++ } else if (rel == dns_namereln_equal) { ++ /* If 'name' is 'apex', no further checking is needed. */ ++ return (false); ++ } ++ ++ /* ++ * If there is a locally served zone between 'apex' and 'name' ++ * then don't cache. ++ */ ++ LOCK(&fctx->res->view->lock); ++ if (fctx->res->view->zonetable != NULL) { ++ unsigned int options = DNS_ZTFIND_NOEXACT; ++ result = dns_zt_find(fctx->res->view->zonetable, name, options, ++ zfname, &zone); ++ if (zone != NULL) { ++ dns_zone_detach(&zone); ++ } ++ if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) { ++ if (dns_name_fullcompare(zfname, apex, &(int){ 0 }, ++ &(unsigned int){ 0U }) == ++ dns_namereln_subdomain) ++ { ++ UNLOCK(&fctx->res->view->lock); ++ return (true); ++ } ++ } ++ } ++ UNLOCK(&fctx->res->view->lock); ++ ++ /* ++ * Look for a forward declaration below 'name'. ++ */ ++ result = dns_fwdtable_find2(fctx->res->view->fwdtable, name, fname, ++ &forwarders); ++ ++ if (ISFORWARDER(fctx->addrinfo)) { ++ /* ++ * See if the forwarder declaration is better. ++ */ ++ if (result == ISC_R_SUCCESS) { ++ return (!dns_name_equal(fname, fctx->fwdname)); ++ } ++ ++ /* ++ * If the lookup failed, the configuration must have ++ * changed: play it safe and don't cache. ++ */ ++ return (true); ++ } else if (result == ISC_R_SUCCESS && ++ forwarders->fwdpolicy == dns_fwdpolicy_only && ++ !ISC_LIST_EMPTY(forwarders->fwdrs)) ++ { ++ /* ++ * If 'name' is covered by a 'forward only' clause then we ++ * can't cache this repsonse. ++ */ ++ return (true); ++ } ++ ++ return (false); ++} ++ + static isc_result_t + check_section(void *arg, dns_name_t *addname, dns_rdatatype_t type, + dns_section_t section) +@@ -6170,7 +6280,7 @@ check_section(void *arg, dns_name_t *addname, dns_rdatatype_t type, + result = dns_message_findname(fctx->rmessage, section, addname, + dns_rdatatype_any, 0, &name, NULL); + if (result == ISC_R_SUCCESS) { +- external = !dns_name_issubdomain(name, &fctx->domain); ++ external = name_external(name, type, fctx); + if (type == dns_rdatatype_a) { + for (rdataset = ISC_LIST_HEAD(name->list); + rdataset != NULL; +@@ -7018,6 +7128,13 @@ answer_response(fetchctx_t *fctx) { + break; + + case dns_namereln_subdomain: ++ /* ++ * Don't accept DNAME from parent namespace. ++ */ ++ if (name_external(name, dns_rdatatype_dname, fctx)) { ++ continue; ++ } ++ + /* + * In-scope DNAME records must have at least + * as many labels as the domain being queried. +@@ -7246,11 +7363,9 @@ answer_response(fetchctx_t *fctx) { + */ + result = dns_message_firstname(message, DNS_SECTION_AUTHORITY); + while (!done && result == ISC_R_SUCCESS) { +- bool external; + name = NULL; + dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name); +- external = !dns_name_issubdomain(name, &fctx->domain); +- if (!external) { ++ if (!name_external(name, dns_rdatatype_ns, fctx)) { + /* + * We expect to find NS or SIG NS rdatasets, and + * nothing else. |