add support for server name indication

d99kris · Jun 15, 2024 · ca49b7c · ca49b7c
1 parent 8ef456b
commit ca49b7c
Show file tree

Hide file tree

Showing 10 changed files with 56 additions and 6 deletions.
diff --git a/README.md b/README.md
@@ -289,6 +289,7 @@ Full example of a config file `~/.nmail/main.conf`:
     smtp_host=smtp.example.com
     smtp_port=587
     smtp_user=
+    sni_enabled=1
     text_to_html_cmd=
     trash=Trash
     [email protected]
@@ -522,6 +523,10 @@ case the email account has different username and password for sending emails
 for sending emails). If not specified, the configured `user` field will be
 used.
 
+### sni_enabled
+
+Controls whether to enable Server Name Indication (SNI) during TLS handshaking.
+
 ### spell_cmd
 
 This field specifies a custom command to use for spell checking composed

diff --git a/src/imap.cpp b/src/imap.cpp
@@ -1,6 +1,6 @@
 // imap.cpp
 //
-// Copyright (c) 2019-2023 Kristofer Berggren
+// Copyright (c) 2019-2024 Kristofer Berggren
 // All rights reserved.
 //
 // nmail is distributed under the MIT license, see LICENSE for details.
@@ -27,6 +27,7 @@ Imap::Imap(const std::string& p_User, const std::string& p_Pass, const std::stri
            const uint16_t p_Port, const int64_t p_Timeout,
            const bool p_CacheEncrypt, const bool p_CacheIndexEncrypt,
            const std::set<std::string>& p_FoldersExclude,
+           const bool p_SniEnabled,
            const std::function<void(const StatusUpdate&)>& p_StatusHandler)
   : m_User(p_User)
   , m_Pass(p_Pass)
@@ -36,6 +37,7 @@ Imap::Imap(const std::string& p_User, const std::string& p_Pass, const std::stri
   , m_CacheEncrypt(p_CacheEncrypt)
   , m_CacheIndexEncrypt(p_CacheIndexEncrypt)
   , m_FoldersExclude(p_FoldersExclude)
+  , m_SniEnabled(p_SniEnabled)
 {
   if (Log::GetTraceEnabled())
   {
@@ -90,6 +92,15 @@ void Imap::CleanupImap()
   }
 }
 
+static void SslContextCallback(struct mailstream_ssl_context* p_SslContext, void* p_Data)
+{
+  if (p_Data != nullptr)
+  {
+    char* host = (char*)p_Data;
+    LOG_IF_IMAP_ERR(mailstream_ssl_set_server_name(p_SslContext, host));
+  }
+}
+
 bool Imap::Login()
 {
   LOG_DEBUG_FUNC(STR());
@@ -105,7 +116,14 @@ bool Imap::Login()
     int rv = 0;
     if (isSSL)
     {
-      rv = LOG_IF_IMAP_ERR(mailimap_ssl_connect(m_Imap, m_Host.c_str(), m_Port));
+      char* sni = (m_SniEnabled && !Util::IsIpAddress(m_Host))
+        ? strdup(m_Host.c_str())
+        : nullptr;
+      rv = LOG_IF_IMAP_ERR(mailimap_ssl_connect_with_callback(m_Imap, m_Host.c_str(), m_Port, SslContextCallback, sni));
+      if (sni != nullptr)
+      {
+        free(sni);
+      }
     }
     else if (isStartTLS)
     {

diff --git a/src/imap.h b/src/imap.h
@@ -1,6 +1,6 @@
 // imap.h
 //
-// Copyright (c) 2019-2023 Kristofer Berggren
+// Copyright (c) 2019-2024 Kristofer Berggren
 // All rights reserved.
 //
 // nmail is distributed under the MIT license, see LICENSE for details.
@@ -48,6 +48,7 @@ class Imap
        const uint16_t p_Port, const int64_t p_Timeout,
        const bool p_CacheEncrypt, const bool p_CacheIndexEncrypt,
        const std::set<std::string>& p_FoldersExclude,
+       const bool p_SniEnabled,
        const std::function<void(const StatusUpdate&)>& p_StatusHandler);
   virtual ~Imap();
 
@@ -109,6 +110,7 @@ class Imap
   bool m_CacheEncrypt = false;
   bool m_CacheIndexEncrypt = false;
   std::set<std::string> m_FoldersExclude;
+  bool m_SniEnabled = false;
 
   std::mutex m_ImapMutex;
   struct mailimap* m_Imap = NULL;

diff --git a/src/imapmanager.cpp b/src/imapmanager.cpp
@@ -20,6 +20,7 @@ ImapManager::ImapManager(const std::string& p_User, const std::string& p_Pass,
                          const bool p_CacheIndexEncrypt,
                          const uint32_t p_IdleTimeout,
                          const std::set<std::string>& p_FoldersExclude,
+                         const bool p_SniEnabled,
                          const std::function<void(const ImapManager::Request&,
                                                   const ImapManager::Response&)>& p_ResponseHandler,
                          const std::function<void(const ImapManager::Action&,
@@ -30,7 +31,7 @@ ImapManager::ImapManager(const std::string& p_User, const std::string& p_Pass,
                          const bool p_IdleInbox,
                          const std::string& p_Inbox)
   : m_Imap(p_User, p_Pass, p_Host, p_Port, p_Timeout,
-           p_CacheEncrypt, p_CacheIndexEncrypt, p_FoldersExclude, p_StatusHandler)
+           p_CacheEncrypt, p_CacheIndexEncrypt, p_FoldersExclude, p_SniEnabled, p_StatusHandler)
   , m_Connect(p_Connect)
   , m_ResponseHandler(p_ResponseHandler)
   , m_ResultHandler(p_ResultHandler)

diff --git a/src/imapmanager.h b/src/imapmanager.h
@@ -117,6 +117,7 @@ class ImapManager
               const bool p_CacheIndexEncrypt,
               const uint32_t p_IdleTimeout,
               const std::set<std::string>& p_FoldersExclude,
+              const bool p_SniEnabled,
               const std::function<void(const ImapManager::Request&, const ImapManager::Response&)>& p_ResponseHandler,
               const std::function<void(const ImapManager::Action&, const ImapManager::Result&)>& p_ResultHandler,
               const std::function<void(const StatusUpdate&)>& p_StatusHandler,

diff --git a/src/main.cpp b/src/main.cpp
@@ -202,6 +202,7 @@ int main(int argc, char* argv[])
     { "file_picker_cmd", "" },
     { "downloads_dir", "" },
     { "idle_timeout", "29" },
+    { "sni_enabled", "1" },
   };
   const std::string mainConfigPath(Util::GetApplicationDir() + std::string("main.conf"));
   std::shared_ptr<Config> mainConfig = std::make_shared<Config>(mainConfigPath, defaultMainConfig);
@@ -283,6 +284,7 @@ int main(int argc, char* argv[])
   Util::SetFilePickerCmd(mainConfig->Get("file_picker_cmd"));
   Util::SetDownloadsDir(mainConfig->Get("downloads_dir"));
   const bool isCoredumpEnabled = (mainConfig->Get("coredump_enabled") == "1");
+  const bool sniEnabled = (mainConfig->Get("sni_enabled") == "1");
 
   // Set logging verbosity level based on config, if not specified with command line arguments
   if (Log::GetVerboseLevel() == Log::INFO_LEVEL)
@@ -394,6 +396,7 @@ int main(int argc, char* argv[])
                                   cacheEncrypt, cacheIndexEncrypt,
                                   idleTimeout,
                                   foldersExclude,
+                                  sniEnabled,
                                   std::bind(&Ui::ResponseHandler, std::ref(ui), std::placeholders::_1,
                                             std::placeholders::_2),
                                   std::bind(&Ui::ResultHandler, std::ref(ui), std::placeholders::_1,

diff --git a/src/nmail.1 b/src/nmail.1
@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH NMAIL "1" "June 2024" "nmail v4.66" "User Commands"
+.TH NMAIL "1" "June 2024" "nmail v4.67" "User Commands"
 .SH NAME
 nmail \- ncurses mail
 .SH SYNOPSIS

diff --git a/src/util.cpp b/src/util.cpp
@@ -22,11 +22,14 @@
 #include <execinfo.h>
 #endif
 #include <libgen.h>
+#include <netdb.h>
 #include <termios.h>
 #include <unistd.h>
 #include <wordexp.h>
 
 #include <sys/resource.h>
+#include <sys/socket.h>
+#include <sys/types.h>
 
 #ifdef __APPLE__
 #include <libproc.h>
@@ -2271,3 +2274,19 @@ std::string Util::ExtractString(const std::string& p_Str, const std::string& p_P
 
   return "";
 }
+
+bool Util::IsIpAddress(const std::string& p_Str)
+{
+  struct addrinfo addrhints;
+  memset(&addrhints, 0, sizeof(struct addrinfo));
+  addrhints.ai_family = AF_UNSPEC;
+  addrhints.ai_flags = AI_NUMERICHOST;
+  struct addrinfo* addr = nullptr;
+  bool rv = (getaddrinfo(p_Str.c_str(), NULL, &addrhints, &addr) == 0);
+  if (rv && (addr != nullptr))
+  {
+    freeaddrinfo(addr);
+  }
+
+  return rv;
+}
diff --git a/src/util.h b/src/util.h
@@ -293,6 +293,7 @@ class Util
   static std::string GetCompiler();
   static std::string GetOsArch();
   static std::string ExtractString(const std::string& p_Str, const std::string& p_Prefix, const std::string& p_Suffix);
+  static bool IsIpAddress(const std::string& p_Str);
 
   template<typename T>
   static inline void Unused(const T& p_Arg)

diff --git a/src/version.cpp b/src/version.cpp
@@ -7,7 +7,7 @@
 
 #include "version.h"
 
-#define NMAIL_VERSION "4.66"
+#define NMAIL_VERSION "4.67"
 
 std::string Version::GetBuildOs()
 {