From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 17 Sep 2025 21:22:36 +0000 (+0200)
Subject: smtp: check EHLO responses case insensitively
X-Git-Tag: rc-8_17_0-3~571
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a827e4294cee78e2169555d4d99c6c5d583d51bc;p=thirdparty%2Fcurl.git

smtp: check EHLO responses case insensitively

Adjust test 980 to announce starttls in lowercase.

Fixes #18588
Reported-by: Joshua Rogers
Closes #18589
---

diff --git a/lib/smtp.c b/lib/smtp.c
index 5dba1f9ea8..84ff693a3c 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -989,19 +989,19 @@ static CURLcode smtp_state_ehlo_resp(struct Curl_easy *data,
     len -= 4;
 
     /* Does the server support the STARTTLS capability? */
-    if(len >= 8 && !memcmp(line, "STARTTLS", 8))
+    if(len >= 8 && curl_strnequal(line, "STARTTLS", 8))
       smtpc->tls_supported = TRUE;
 
     /* Does the server support the SIZE capability? */
-    else if(len >= 4 && !memcmp(line, "SIZE", 4))
+    else if(len >= 4 && curl_strnequal(line, "SIZE", 4))
       smtpc->size_supported = TRUE;
 
     /* Does the server support the UTF-8 capability? */
-    else if(len >= 8 && !memcmp(line, "SMTPUTF8", 8))
+    else if(len >= 8 && curl_strnequal(line, "SMTPUTF8", 8))
       smtpc->utf8_supported = TRUE;
 
     /* Does the server support authentication? */
-    else if(len >= 5 && !memcmp(line, "AUTH ", 5)) {
+    else if(len >= 5 && curl_strnequal(line, "AUTH ", 5)) {
       smtpc->auth_supported = TRUE;
 
       /* Advance past the AUTH keyword */
diff --git a/tests/data/test980 b/tests/data/test980
index 5811b437d4..8a52559472 100644
--- a/tests/data/test980
+++ b/tests/data/test980
@@ -10,7 +10,7 @@ STARTTLS
 # Server-side
 <reply>
 <servercmd>
-CAPA STARTTLS
+CAPA starttls
 AUTH PLAIN
 REPLY STARTTLS 454 currently unavailable\r\n235 Authenticated\r\n250 2.1.0 Sender ok\r\n250 2.1.5 Recipient ok\r\n354 Enter mail\r\n250 2.0.0 Accepted
 REPLY AUTH 535 5.7.8 Authentication credentials invalid