dropbear: backport add ip address to exit without auth messages

[openwrt/openwrt.git] / package / network / services / dropbear / patches / 010-backport-change-address-logging.patch

diff --git a/package/network/services/dropbear/patches/010-backport-change-address-logging.patch b/package/network/services/dropbear/patches/010-backport-change-address-logging.patch
new file mode 100644 (file)
index 0000000..2b99f81
--- /dev/null
+++ b/package/network/services/dropbear/patches/010-backport-change-address-logging.patch
@@ -0,0 +1,119 @@
+From c153b3612b7c9f24a0f5af43618a646545ed6e22 Mon Sep 17 00:00:00 2001
+From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Date: Mon, 30 Sep 2019 12:42:13 +0100
+Subject: [PATCH] Improve address logging on early exit messages
+
+Change 'Early exit' and 'Exit before auth' messages to include the IP
+address & port as part of the message.
+
+This allows log scanning utilities such as 'fail2ban' to obtain the
+offending IP address as part of the failure event instead of extracting
+the PID from the message and then scanning the log again for match
+'child connection from' messages
+
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+---
+ svr-auth.c    | 18 +++++++-----------
+ svr-session.c | 20 ++++++++++++++------
+ 2 files changed, 21 insertions(+), 17 deletions(-)
+
+--- a/svr-auth.c
++++ b/svr-auth.c
+@@ -241,8 +241,7 @@ static int checkusername(const char *use
+       }
+ 
+       if (strlen(username) != userlen) {
+-              dropbear_exit("Attempted username with a null byte from %s",
+-                      svr_ses.addrstring);
++              dropbear_exit("Attempted username with a null byte");
+       }
+ 
+       if (ses.authstate.username == NULL) {
+@@ -252,8 +251,7 @@ static int checkusername(const char *use
+       } else {
+               /* check username hasn't changed */
+               if (strcmp(username, ses.authstate.username) != 0) {
+-                      dropbear_exit("Client trying multiple usernames from %s",
+-                              svr_ses.addrstring);
++                      dropbear_exit("Client trying multiple usernames");
+               }
+       }
+ 
+@@ -268,8 +266,7 @@ static int checkusername(const char *use
+       if (!ses.authstate.pw_name) {
+               TRACE(("leave checkusername: user '%s' doesn't exist", username))
+               dropbear_log(LOG_WARNING,
+-                              "Login attempt for nonexistent user from %s",
+-                              svr_ses.addrstring);
++                              "Login attempt for nonexistent user");
+               ses.authstate.checkusername_failed = 1;
+               return DROPBEAR_FAILURE;
+       }
+@@ -279,9 +276,8 @@ static int checkusername(const char *use
+       if (!(DROPBEAR_SVR_MULTIUSER && uid == 0) && uid != ses.authstate.pw_uid) {
+               TRACE(("running as nonroot, only server uid is allowed"))
+               dropbear_log(LOG_WARNING,
+-                              "Login attempt with wrong user %s from %s",
+-                              ses.authstate.pw_name,
+-                              svr_ses.addrstring);
++                              "Login attempt with wrong user %s",
++                              ses.authstate.pw_name);
+               ses.authstate.checkusername_failed = 1;
+               return DROPBEAR_FAILURE;
+       }
+@@ -440,8 +436,8 @@ void send_msg_userauth_failure(int parti
+               } else {
+                       userstr = ses.authstate.pw_name;
+               }
+-              dropbear_exit("Max auth tries reached - user '%s' from %s",
+-                              userstr, svr_ses.addrstring);
++              dropbear_exit("Max auth tries reached - user '%s'",
++                              userstr);
+       }
+       
+       TRACE(("leave send_msg_userauth_failure"))
+--- a/svr-session.c
++++ b/svr-session.c
+@@ -149,28 +149,36 @@ void svr_session(int sock, int childpipe
+ void svr_dropbear_exit(int exitcode, const char* format, va_list param) {
+       char exitmsg[150];
+       char fullmsg[300];
++      char fromaddr[60];
+       int i;
+ 
+       /* Render the formatted exit message */
+       vsnprintf(exitmsg, sizeof(exitmsg), format, param);
+ 
++      /* svr_ses.addrstring may not be set for some early exits, or for
++      the listener process */
++      fromaddr[0] = '\0';
++      if (svr_ses.addrstring) {
++          snprintf(fromaddr, sizeof(fromaddr), " from <%s>", svr_ses.addrstring);
++    }
++
+       /* Add the prefix depending on session/auth state */
+       if (!ses.init_done) {
+               /* before session init */
+-              snprintf(fullmsg, sizeof(fullmsg), "Early exit: %s", exitmsg);
++              snprintf(fullmsg, sizeof(fullmsg), "Early exit%s: %s", fromaddr, exitmsg);
+       } else if (ses.authstate.authdone) {
+               /* user has authenticated */
+               snprintf(fullmsg, sizeof(fullmsg),
+-                              "Exit (%s): %s", 
+-                              ses.authstate.pw_name, exitmsg);
++                              "Exit (%s)%s: %s", 
++                              ses.authstate.pw_name, fromaddr, exitmsg);
+       } else if (ses.authstate.pw_name) {
+               /* we have a potential user */
+               snprintf(fullmsg, sizeof(fullmsg), 
+-                              "Exit before auth (user '%s', %u fails): %s",
+-                              ses.authstate.pw_name, ses.authstate.failcount, exitmsg);
++                              "Exit before auth%s: (user '%s', %u fails): %s",
++                              fromaddr, ses.authstate.pw_name, ses.authstate.failcount, exitmsg);
+       } else {
+               /* before userauth */
+-              snprintf(fullmsg, sizeof(fullmsg), "Exit before auth: %s", exitmsg);
++              snprintf(fullmsg, sizeof(fullmsg), "Exit before auth%s: %s", fromaddr, exitmsg);
+       }
+ 
+       dropbear_log(LOG_INFO, "%s", fullmsg);