From 2541ff391fc88d2fc378c4fa9374f8b1a3e4e9b9 Mon Sep 17 00:00:00 2001 From: Christian Marangi Date: Mon, 29 Apr 2024 21:17:31 +0200 Subject: [PATCH] procd: make mDNS TXT record parsing more solid mDNS broadcast can't accept empty TXT record and would fail registration. Current procd_add_mdns_service checks only if the first passed arg is empty but don't make any verification on the other args permittins insertion of empty values in TXT record. Example: procd_add_mdns "blah" \ "tcp" "50" \ "1" \ "" \ "3" Produce: { "blah_50": { "service": "_blah._tcp.local", "port": 50, "txt": [ "1", "", "3" ] } } The middle empty TXT record should never be included as it's empty. This can happen with scripts that make fragile parsing and include variables even if they are empty. Prevent this and make the TXT record more solid by checking every provided TXT record and include only the non-empty ones. The fixed JSON is the following: { "blah_50": { "service": "_blah._tcp.local", "port": 50, "txt": [ "1", "3" ] } } Fixes: b0d9dcf84dd0 ("procd: update to latest git HEAD") Reported-by: Paul Donald Link: https://github.com/openwrt/openwrt/pull/15331 Signed-off-by: Christian Marangi (cherry picked from commit 4b043047132de0b3d90619d538f103af6153fa5a) --- package/system/procd/files/procd.sh | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/package/system/procd/files/procd.sh b/package/system/procd/files/procd.sh index 5148b2f03c..d834fa601a 100644 --- a/package/system/procd/files/procd.sh +++ b/package/system/procd/files/procd.sh @@ -570,18 +570,21 @@ _procd_set_config_changed() { } procd_add_mdns_service() { - local service proto port + local service proto port txt_count=0 service=$1; shift proto=$1; shift port=$1; shift json_add_object "${service}_$port" json_add_string "service" "_$service._$proto.local" json_add_int port "$port" - [ -n "$1" ] && { - json_add_array txt - for txt in "$@"; do json_add_string "" "$txt"; done - json_select .. - } + for txt in "$@"; do + [ -z "$txt" ] && continue + txt_count=$((txt_count+1)) + [ $txt_count -eq 1 ] && json_add_array txt + json_add_string "" "$txt" + done + [ $txt_count -gt 0 ] && json_select .. + json_select .. }