diff --git a/package/utils/busybox/patches/530-nslookup-ensure-unique-transaction-IDs-for-the-DNS-queries.patch b/package/utils/busybox/patches/530-nslookup-ensure-unique-transaction-IDs-for-the-DNS-queries.patch new file mode 100644 index 0000000000000000000000000000000000000000..caa5ee78f35ad3195a61fec3af628b3816df2dd4 --- /dev/null +++ b/package/utils/busybox/patches/530-nslookup-ensure-unique-transaction-IDs-for-the-DNS-queries.patch @@ -0,0 +1,42 @@ +From: Uwe Kleine-König +Date: Sat, 8 Oct 2022 19:22:52 +0200 +Subject: [PATCH] nslookup: ensure unique transaction IDs for the DNS queries + +The transaction IDs generated by res_mkquery() for both glibc and musl only +depends on the state of the monotonic clock. +For some machines (here: a TP-Link RE200 powered by a MediaTek MT7620A) +the monotonic clock has a coarse resolution (here: 20 µs) and it can happen +that the requests for A and AAAA share the same transaction ID. + +In that case the mapping from received responses to the sent queries +doesn't work and name resolution fails as follows: + + # /bin/busybox nslookup heise.de + Server: 127.0.0.1 + Address: 127.0.0.1:53 + + Non-authoritative answer: + Name: heise.de + Address: 193.99.144.80 + + *** Can't find heise.de: No answer + +because the AAAA reply is dropped as a duplicate reply to the A query. + +To prevent this make sure the transaction IDs are unique. + +Forwarded: http://lists.busybox.net/pipermail/busybox/2022-October/089911.html +--- +--- a/networking/nslookup.c ++++ b/networking/nslookup.c +@@ -978,6 +978,10 @@ int nslookup_main(int argc UNUSED_PARAM, + } + } + ++ /* Ensure the Transaction IDs are unique */ ++ for (rc = 1; rc < G.query_count; rc++) ++ G.query[rc].query[1] = G.query[rc - 1].query[1] + 1; ++ + for (rc = 0; rc < G.serv_count;) { + int c; +