proxy.c: Clear sensitive data after use

Usage of credentials  is a bit odd in this file.
Actually the copy of "struct user_pass" kept in p->up is not
required at all. It just defeats the purpose of auth-nocahe
as it never gets cleared.

Removing it is beyond the scope of this patch -- we just ensure
it's purged after use.

Change-Id: Ic6d63a319d272a56ac0e278f1356bc5241b56a34
Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20240905100724.4105-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg29061.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit dbe7e456954bf001420c4552c2b6e184ec6e068c)

diff --git a/src/openvpn/proxy.c b/src/openvpn/proxy.c
index f6475fbe6d60f3884fc6783025283f25ad5caae6..26882618432a86194e8290d674c808efd52a2aa0 100644 (file)
--- a/src/openvpn/proxy.c
+++ b/src/openvpn/proxy.c
@@ -247,7 +247,9 @@ username_password_as_base64(const struct http_proxy_info *p,
     struct buffer out = alloc_buf_gc(strlen(p->up.username) + strlen(p->up.password) + 2, gc);
     ASSERT(strlen(p->up.username) > 0);
     buf_printf(&out, "%s:%s", p->up.username, p->up.password);
-    return (const char *)make_base64_string((const uint8_t *)BSTR(&out), gc);
+    char *ret = (char *)make_base64_string((const uint8_t *)BSTR(&out), gc);
+    secure_memzero(BSTR(&out), out.len);
+    return ret;
 }
 
 static void
@@ -737,6 +739,9 @@ establish_http_proxy_passthru(struct http_proxy_info *p,
                 ASSERT(0);
         }
 
+        /* clear any sensitive content in buf */
+        secure_memzero(buf, sizeof(buf));
+
         /* send empty CR, LF */
         if (!send_crlf(sd))
         {
@@ -978,6 +983,8 @@ establish_http_proxy_passthru(struct http_proxy_info *p,
                 {
                     goto error;
                 }
+                /* clear any sensitive content in buf */
+                secure_memzero(buf, sizeof(buf));
 
                 /* receive reply from proxy */
                 if (!recv_line(sd, buf, sizeof(buf), get_server_poll_remaining_time(server_poll_timeout), true, NULL, signal_received))
@@ -1081,10 +1088,12 @@ establish_http_proxy_passthru(struct http_proxy_info *p,
 #endif
 
 done:
+    purge_user_pass(&p->up, true);
     gc_free(&gc);
     return ret;
 
 error:
+    purge_user_pass(&p->up, true);
     register_signal(sig_info, SIGUSR1, "HTTP proxy error"); /* SOFT-SIGUSR1 -- HTTP proxy error */
     gc_free(&gc);
     return ret;