From 1330a092fae83fbd831fb51f648209d1ed3b7bff Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 16 Feb 2021 14:02:09 -0800
Subject: [PATCH] Clean email headers and warn on unsupported address format
Just in case, make sure CR or NL don't end up in
an email header.
---
notify/smtp.sh | 55 +++++++++++++++++++++++++++-----------------------
1 file changed, 30 insertions(+), 25 deletions(-)
diff --git a/notify/smtp.sh b/notify/smtp.sh
index 43536cd2..42c1487c 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -53,16 +53,28 @@ smtp_send() {
_saveaccountconf_mutable_default SMTP_BIN "$SMTP_BIN"
SMTP_FROM="$(_readaccountconf_mutable_default SMTP_FROM)"
+ SMTP_FROM="$(_clean_email_header "$SMTP_FROM")"
if [ -z "$SMTP_FROM" ]; then
_err "You must define SMTP_FROM as the sender email address."
return 1
fi
+ if _email_has_display_name "$SMTP_FROM"; then
+ _err "SMTP_FROM must be only a simple email address (sender@example.com)."
+ _err "Change your SMTP_FROM='$SMTP_FROM' to remove the display name."
+ return 1
+ fi
_debug SMTP_FROM "$SMTP_FROM"
_saveaccountconf_mutable_default SMTP_FROM "$SMTP_FROM"
SMTP_TO="$(_readaccountconf_mutable_default SMTP_TO)"
+ SMTP_TO="$(_clean_email_header "$SMTP_TO")"
if [ -z "$SMTP_TO" ]; then
- _err "You must define SMTP_TO as the recipient email address."
+ _err "You must define SMTP_TO as the recipient email address(es)."
+ return 1
+ fi
+ if _email_has_display_name "$SMTP_TO"; then
+ _err "SMTP_TO must be only simple email addresses (to@example.com,to2@example.com)."
+ _err "Change your SMTP_TO='$SMTP_TO' to remove the display name(s)."
return 1
fi
_debug SMTP_TO "$SMTP_TO"
@@ -111,7 +123,7 @@ smtp_send() {
_debug SMTP_TIMEOUT "$SMTP_TIMEOUT"
_saveaccountconf_mutable_default SMTP_TIMEOUT "$SMTP_TIMEOUT" "$SMTP_TIMEOUT_DEFAULT"
- SMTP_X_MAILER="${PROJECT_NAME} ${VER} --notify-hook smtp"
+ SMTP_X_MAILER="$(_clean_email_header "$PROJECT_NAME $VER --notify-hook smtp")"
# Run with --debug 2 (or above) to echo the transcript of the SMTP session.
# Careful: this may include SMTP_PASSWORD in plaintext!
@@ -121,6 +133,7 @@ smtp_send() {
SMTP_SHOW_TRANSCRIPT=""
fi
+ SMTP_SUBJECT=$(_clean_email_header "$SMTP_SUBJECT")
_debug SMTP_SUBJECT "$SMTP_SUBJECT"
_debug SMTP_CONTENT "$SMTP_CONTENT"
@@ -146,28 +159,26 @@ smtp_send() {
return 0
}
+# Strip CR and NL from text to prevent MIME header injection
+# text
+_clean_email_header() {
+ printf "%s" "$(echo "$1" | tr -d "\r\n")"
+}
+
+# Simple check for display name in an email address (< > or ")
+# email
+_email_has_display_name() {
+ _email="$1"
+ expr "$_email" : '^.*[<>"]' >/dev/null
+}
+
##
## curl smtp sending
##
# Send the message via curl using SMTP_* variables
_smtp_send_curl() {
- # curl passes --mail-from and --mail-rcpt directly to the SMTP protocol without
- # additional parsing, and SMTP requires addr-spec only (no display names).
- # In the future, maybe try to parse the addr-spec out for curl args (non-trivial).
- if _email_has_display_name "$SMTP_FROM"; then
- _err "curl smtp only allows a simple email address in SMTP_FROM."
- _err "Change your SMTP_FROM='$SMTP_FROM' to remove the display name."
- return 1
- fi
- if _email_has_display_name "$SMTP_TO"; then
- _err "curl smtp only allows simple email addresses in SMTP_TO."
- _err "Change your SMTP_TO='$SMTP_TO' to remove the display name(s)."
- return 1
- fi
-
# Build curl args in $@
-
case "$SMTP_SECURE" in
none)
set -- --url "smtp://${SMTP_HOST}:${SMTP_PORT}"
@@ -219,7 +230,8 @@ _smtp_send_curl() {
echo "$raw_message" | "$SMTP_BIN" "$@"
}
-# Output an RFC-822 / RFC-5322 email message using SMTP_* variables
+# Output an RFC-822 / RFC-5322 email message using SMTP_* variables.
+# (This assumes variables have already been cleaned for use in email headers.)
_smtp_raw_message() {
echo "From: $SMTP_FROM"
echo "To: $SMTP_TO"
@@ -259,13 +271,6 @@ _rfc2822_date() {
LC_TIME="$_old_lc_time"
}
-# Simple check for display name in an email address (< > or ")
-# email
-_email_has_display_name() {
- _email="$1"
- expr "$_email" : '^.*[<>"]' >/dev/null
-}
-
##
## Python smtp sending
##