diff options
| author | Martin Pitt <martin.pitt@ubuntu.com> | 2016-06-24 07:54:28 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2016-06-24 07:54:28 +0200 |
| commit | ceeddf79b8464469a5307a1030862c7c4fe289e9 (patch) | |
| tree | 4ad0a49ca457e8e53789c3aea41c6284ab3ff277 /src/resolve | |
| parent | a2c28c645160b4e9377db4cb40cb9f22141f2dd3 (diff) | |
resolved: add option to disable caching (#3592)
In some cases, caching DNS results locally is not desirable, a it makes DNS
cache poisoning attacks a tad easier and also allows users on the system to
determine whether or not a particular domain got visited by another user. Thus
provide a new "Cache" resolved.conf option to disable it.
Diffstat (limited to 'src/resolve')
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 4 | ||||
| -rw-r--r-- | src/resolve/resolved-gperf.gperf | 1 | ||||
| -rw-r--r-- | src/resolve/resolved-manager.c | 1 | ||||
| -rw-r--r-- | src/resolve/resolved-manager.h | 1 | ||||
| -rw-r--r-- | src/resolve/resolved.conf.in | 1 |
5 files changed, 8 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 09f60d3e76..06e7145422 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -590,6 +590,10 @@ static void dns_transaction_cache_answer(DnsTransaction *t) { if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) return; + /* Caching disabled? */ + if (!t->scope->manager->enable_cache) + return; + /* We never cache if this packet is from the local host, under * the assumption that a locally running DNS server would * cache this anyway, and probably knows better when to flush diff --git a/src/resolve/resolved-gperf.gperf b/src/resolve/resolved-gperf.gperf index 82f26215df..2fd56bce26 100644 --- a/src/resolve/resolved-gperf.gperf +++ b/src/resolve/resolved-gperf.gperf @@ -19,3 +19,4 @@ Resolve.FallbackDNS, config_parse_dns_servers, DNS_SERVER_FALLBACK, 0 Resolve.Domains, config_parse_search_domains, 0, 0 Resolve.LLMNR, config_parse_resolve_support, 0, offsetof(Manager, llmnr_support) Resolve.DNSSEC, config_parse_dnssec_mode, 0, offsetof(Manager, dnssec_mode) +Resolve.Cache, config_parse_bool, 0, offsetof(Manager, enable_cache) diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index 30036049da..add463b6a9 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -500,6 +500,7 @@ int manager_new(Manager **ret) { m->llmnr_support = RESOLVE_SUPPORT_YES; m->mdns_support = RESOLVE_SUPPORT_NO; m->dnssec_mode = DEFAULT_DNSSEC_MODE; + m->enable_cache = true; m->read_resolv_conf = true; m->need_builtin_fallbacks = true; m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY; diff --git a/src/resolve/resolved-manager.h b/src/resolve/resolved-manager.h index 114fec7927..deebd8e484 100644 --- a/src/resolve/resolved-manager.h +++ b/src/resolve/resolved-manager.h @@ -46,6 +46,7 @@ struct Manager { ResolveSupport llmnr_support; ResolveSupport mdns_support; DnssecMode dnssec_mode; + bool enable_cache; /* Network */ Hashmap *links; diff --git a/src/resolve/resolved.conf.in b/src/resolve/resolved.conf.in index a288588924..3bd8389c88 100644 --- a/src/resolve/resolved.conf.in +++ b/src/resolve/resolved.conf.in @@ -17,3 +17,4 @@ #Domains= #LLMNR=yes #DNSSEC=@DEFAULT_DNSSEC_MODE@ +#Cache=yes |