From bf5bf60e73b97d25a07818acfd7c345d8004659e Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Wed, 29 Dec 2021 20:41:18 +0100
Subject: ircsink: add support for PLAIN SASL

---
 bin/ircsink | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/bin/ircsink b/bin/ircsink
index 4e1a844..3d1b0df 100755
--- a/bin/ircsink
+++ b/bin/ircsink
@@ -17,6 +17,21 @@
 #
 #   --port=PORT (default: 6667, or 6697 if --secure is specified)
 #
+#   --sasl=plain
+#     If specified, then use the PLAIN SASL mechanism.
+#
+#   --sasl-pass=@FILE
+#   --sasl-pass=$VAR
+#   --sasl-pass="PASS
+#     Password to be used for SASL authentication, which can be read either
+#     from a file, an environment variable, or passed in as argument.
+#
+#     Note: the characters @, $, and " have to be verbatim and might need to be
+#     quoted in the shell, e.g. ircsink --sasl-pass=\$SASL_PASS
+#
+#   --sasl-user=USER (default: NICK)
+#     User to be used for SASL authentication.
+#
 #   --secure
 #     If specified, then the connection will be made using openssl.
 #     Otherwise netcat will be used.
@@ -35,7 +50,7 @@ main() {(
   exec 3<&0
 
   _args=$(getopt -n "$0" -s sh \
-      -l help,nick:,port:,secure,server:,target: \
+      -l help,nick:,port:,sasl:,sasl-pass:,sasl-user:,secure,server:,target: \
       -- "$0" "$@")
   eval set -- "$_args"
   unset _args
@@ -43,6 +58,9 @@ main() {(
   help=
   nick=
   port=
+  sasl_mech=
+  sasl_pass=
+  sasl_user=
   secure=
   server=
   target=
@@ -51,6 +69,20 @@ main() {(
       --help) help=1; shift;;
       --nick) nick=$2; shift 2;;
       --port) port=$2; shift 2;;
+      --sasl)
+        case $2 in
+          plain) sasl_mech=$2; shift 2;;
+          *) echo "$0: unsupported SASL mechanism: $2" >&2; exit 1;;
+        esac
+        ;;
+      --sasl-pass)
+        case $2 in
+          \@*) sasl_pass=$(cat "${2:1}"); shift 2;;
+          \$*) sasl_pass=$(env | awk -F= -v name="${2:1}" '$1==name{print$2}'); shift 2;;
+          \"*) sasl_pass=${2:1}; shift 2;;
+          *) echo "$0: don't know how to get SASL password: $2" >&2; exit 1;;
+        esac
+        ;;
       --secure) secure=1; shift;;
       --server) server=$2; shift 2;;
       --target) target=$2; shift 2;;
@@ -77,6 +109,15 @@ main() {(
     nick=$(hostname)
   fi
 
+  if test -n "$sasl_mech" && test -z "$sasl_user"; then
+    sasl_user=$nick
+  fi
+
+  if test -n "$sasl_mech" && test -z "$secure"; then
+    echo "$0: error: cannot use --sasl without --secure" >&2
+    exit 1
+  fi
+
   if test -z "$port"; then
     case $secure in
       '') port=6667;;
@@ -158,6 +199,21 @@ main() {(
       s/^PING (:.*)/PONG \1/p
     '
 
+    case $sasl_mech in
+      plain)
+        echo2 "CAP REQ :sasl"
+        sed -nru '/^:[^ ]* CAP [0-9A-Za-z]+ ACK sasl/q'
+
+        echo2 "AUTHENTICATE PLAIN"
+        sed -nru '/^:[^ ]* AUTHENTICATE +/q'
+
+        echo sasl user: $sasl_user >&2
+        message=$(printf '\0%s\0%s' "$sasl_user" "$sasl_pass" | base64)
+        echo "AUTHENTICATE $message"
+        echo "AUTHENTICATE ***REDACTED***" >&2
+        ;;
+    esac
+
     if is_channel "$target"; then
       echo2 "JOIN $target"
     fi
-- 
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