Backport of:

From 8f4608468b890dce2dad9f91d5607ee7e9c1aba1 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Thu, 9 Mar 2023 17:47:06 +0100
Subject: [PATCH] ftp: add more conditions for connection reuse

Reported-by: Harry Sintonen
Closes #10730
---
 lib/ftp.c     | 28 ++++++++++++++++++++++++++--
 lib/ftp.h     |  5 +++++
 lib/setopt.c  |  2 +-
 lib/url.c     | 17 +++++++++++++++--
 lib/urldata.h |  4 ++--
 5 files changed, 49 insertions(+), 7 deletions(-)

--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -4095,6 +4095,8 @@ static CURLcode ftp_disconnect(struct Cu
   }
 
   freedirs(ftpc);
+  Curl_safefree(ftpc->account);
+  Curl_safefree(ftpc->alternative_to_user);
   Curl_safefree(ftpc->prevpath);
   Curl_safefree(ftpc->server_os);
   Curl_pp_disconnect(pp);
@@ -4298,11 +4300,31 @@ static CURLcode ftp_setup_connection(str
   struct Curl_easy *data = conn->data;
   char *type;
   struct FTP *ftp;
+  struct ftp_conn *ftpc = &conn->proto.ftpc;
 
-  conn->data->req.p.ftp = ftp = calloc(sizeof(struct FTP), 1);
+  ftp = calloc(sizeof(struct FTP), 1);
   if(NULL == ftp)
     return CURLE_OUT_OF_MEMORY;
 
+  /* clone connection related data that is FTP specific */
+  if(data->set.str[STRING_FTP_ACCOUNT]) {
+    ftpc->account = strdup(data->set.str[STRING_FTP_ACCOUNT]);
+    if(!ftpc->account) {
+      free(ftp);
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+  if(data->set.str[STRING_FTP_ALTERNATIVE_TO_USER]) {
+    ftpc->alternative_to_user =
+      strdup(data->set.str[STRING_FTP_ALTERNATIVE_TO_USER]);
+    if(!ftpc->alternative_to_user) {
+      Curl_safefree(ftpc->account);
+      free(ftp);
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+  data->req.p.ftp = ftp;
+
   ftp->path = &data->state.up.path[1]; /* don't include the initial slash */
 
   /* FTP URLs support an extension like ";type=<typecode>" that
@@ -4399,7 +4421,9 @@ static CURLcode ftp_setup_connection(str
   /* get some initial data into the ftp struct */
   ftp->transfer = FTPTRANSFER_BODY;
   ftp->downloadsize = 0;
-  conn->proto.ftpc.known_filesize = -1; /* unknown size for now */
+  ftpc->known_filesize = -1; /* unknown size for now */
+  ftpc->use_ssl = data->set.use_ssl;
+  ftpc->ccc = data->set.ftp_ccc;
 
   return CURLE_OK;
 }
--- a/lib/ftp.h
+++ b/lib/ftp.h
@@ -115,6 +115,8 @@ struct FTP {
    struct */
 struct ftp_conn {
   struct pingpong pp;
+  char *account;
+  char *alternative_to_user;
   char *entrypath; /* the PWD reply when we logged on */
   char **dirs;   /* realloc()ed array for path components */
   int dirdepth;  /* number of entries used in the 'dirs' array */
@@ -144,6 +146,9 @@ struct ftp_conn {
   ftpstate state; /* always use ftp.c:state() to change state! */
   ftpstate state_saved; /* transfer type saved to be reloaded after
                            data connection is established */
+  unsigned char use_ssl;   /* if AUTH TLS is to be attempted etc, for FTP or
+                              IMAP or POP3 or others! (type: curl_usessl)*/
+  unsigned char ccc;       /* ccc level for this connection */
   curl_off_t retr_size_saved; /* Size of retrieved file saved */
   char *server_os;     /* The target server operating system. */
   curl_off_t known_filesize; /* file size is different from -1, if wildcard
--- a/lib/setopt.c
+++ b/lib/setopt.c
@@ -2327,7 +2327,7 @@ CURLcode Curl_vsetopt(struct Curl_easy *
     arg = va_arg(param, long);
     if((arg < CURLUSESSL_NONE) || (arg >= CURLUSESSL_LAST))
       return CURLE_BAD_FUNCTION_ARGUMENT;
-    data->set.use_ssl = (curl_usessl)arg;
+    data->set.use_ssl = (unsigned char)arg;
     break;
 
   case CURLOPT_SSL_OPTIONS:
--- a/lib/url.c
+++ b/lib/url.c
@@ -1303,11 +1303,24 @@ ConnectionExists(struct Curl_easy *data,
          and auth method, but this check takes precaution before efficiency */
       if(needle->gssapi_delegation != check->gssapi_delegation)
         continue;
-
-      if(get_protocol_family(needle->handler) & PROTO_FAMILY_SSH) {
+#ifdef USE_SSH
+      else if(get_protocol_family(needle->handler) & PROTO_FAMILY_SSH) {
         if(!ssh_config_matches(needle, check))
           continue;
       }
+#endif
+#ifndef CURL_DISABLE_FTP
+      else if(get_protocol_family(needle->handler) & PROTO_FAMILY_FTP) {
+        /* Also match ACCOUNT, ALTERNATIVE-TO-USER, USE_SSL and CCC options */
+        if(Curl_timestrcmp(needle->proto.ftpc.account,
+                           check->proto.ftpc.account) ||
+           Curl_timestrcmp(needle->proto.ftpc.alternative_to_user,
+                           check->proto.ftpc.alternative_to_user) ||
+           (needle->proto.ftpc.use_ssl != check->proto.ftpc.use_ssl) ||
+           (needle->proto.ftpc.ccc != check->proto.ftpc.ccc))
+          continue;
+      }
+#endif
 
       if((needle->handler->flags&PROTOPT_SSL)
 #ifndef CURL_DISABLE_PROXY
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1741,8 +1741,6 @@ struct UserDefined {
   void *ssh_keyfunc_userp;         /* custom pointer to callback */
   enum CURL_NETRC_OPTION
        use_netrc;        /* defined in include/curl.h */
-  curl_usessl use_ssl;   /* if AUTH TLS is to be attempted etc, for FTP or
-                            IMAP or POP3 or others! */
   long new_file_perms;    /* Permissions to use when creating remote files */
   long new_directory_perms; /* Permissions to use when creating remote dirs */
   long ssh_auth_types;   /* allowed SSH auth types */
@@ -1882,6 +1880,8 @@ struct UserDefined {
   BIT(http09_allowed); /* allow HTTP/0.9 responses */
   BIT(mail_rcpt_allowfails); /* allow RCPT TO command to fail for some
                                 recipients */
+  unsigned char use_ssl;   /* if AUTH TLS is to be attempted etc, for FTP or
+                              IMAP or POP3 or others! (type: curl_usessl)*/
 };
 
 struct Names {