diff options
Diffstat (limited to 'debian/patches/edns0.patch')
| -rw-r--r-- | debian/patches/edns0.patch | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/debian/patches/edns0.patch b/debian/patches/edns0.patch new file mode 100644 index 0000000..bb0caf6 --- /dev/null +++ b/debian/patches/edns0.patch @@ -0,0 +1,58 @@ +From: Michael Tokarev <mjt@tls.msk.ru> +Subject: Minimal EDNS0 support for built-in DNS client +Date: Mon, 26 Feb 2024 14:15:00 +0300 +Forwarded: yes +Bug: https://bugzilla.samba.org/show_bug.cgi?id=15536 + +Currently, samba built-in DNS client is UDP-only (it does +support TCP mode, but not all components use it). In +particular, when winbind queries list of AD DCs (SRV +record) which can be quite large, it uses UDP-only query. +And at the same time, samba DNS client does not support +EDNS0 at all, so the reply is limited to standard DNS +packet size which is 512 bytes. + +Add minimal EDNS0 OPT record to ADDITIONAL section when +sending a DNS request out, indicating we can accept +DNS packets up to 4Kb in size. + +Since DNSSEC is in wide use today and DNSSEC requires +EDNS0, it is okay to assume ENDS0 is widely supported +these days, so there should be no regressions when +enabling EDNS0. + +Signed-off-by: Michael Tokarev <mjt@tls.msk.ru> + +diff --git a/libcli/dns/dns.c b/libcli/dns/dns.c +index 943b4d5b33e..81144601bb8 100644 +--- a/libcli/dns/dns.c ++++ b/libcli/dns/dns.c +@@ -422,6 +422,7 @@ struct tevent_req *dns_cli_request_send(TALLOC_CTX *mem_ctx, + struct dns_cli_request_state *state; + struct dns_name_question question; + struct dns_name_packet out_packet; ++ struct dns_res_rec edns0_opt; + enum ndr_err_code ndr_err; + + req = tevent_req_create(mem_ctx, &state, +@@ -443,11 +444,19 @@ struct tevent_req *dns_cli_request_send(TALLOC_CTX *mem_ctx, + .question_type = qtype, .question_class = qclass + }; + ++ edns0_opt = (struct dns_res_rec) { ++ .name = "", ++ .rr_type = DNS_QTYPE_OPT, ++ .rr_class = 4096 /* 4096 bytes UDP buffer size */ ++ }; ++ + out_packet = (struct dns_name_packet) { + .id = state->req_id, + .operation = DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED, + .qdcount = 1, +- .questions = &question ++ .questions = &question, ++ .arcount = 1, ++ .additional = &edns0_opt + }; + + ndr_err = ndr_push_struct_blob( |