+++ /dev/null
-From 256e2abb8150f9fea33cd026597dbe70f0379296 Mon Sep 17 00:00:00 2001
-From: Matt Johnston <matt@ucc.asn.au>
-Date: Thu, 23 Aug 2018 23:43:12 +0800
-Subject: [PATCH] Wait to fail invalid usernames
-
-Wait to fail invalid usernames
-
-Upstream-Status: Backport [https://secure.ucc.asn.au/hg/dropbear/rev/5d2d1021ca00]
-CVE: CVE-2018-15599
-Signed-off-by: Mingli Yu <Mingli.Yu@windriver.com>
----
- auth.h | 6 +++---
- svr-auth.c | 19 +++++--------------
- svr-authpam.c | 26 ++++++++++++++++++++++----
- svr-authpasswd.c | 27 ++++++++++++++-------------
- svr-authpubkey.c | 11 ++++++++++-
- 5 files changed, 54 insertions(+), 35 deletions(-)
-
-diff --git a/auth.h b/auth.h
-index da498f5..98f5468 100644
---- a/auth.h
-+++ b/auth.h
-@@ -37,9 +37,9 @@ void recv_msg_userauth_request(void);
- void send_msg_userauth_failure(int partial, int incrfail);
- void send_msg_userauth_success(void);
- void send_msg_userauth_banner(const buffer *msg);
--void svr_auth_password(void);
--void svr_auth_pubkey(void);
--void svr_auth_pam(void);
-+void svr_auth_password(int valid_user);
-+void svr_auth_pubkey(int valid_user);
-+void svr_auth_pam(int valid_user);
-
- #if DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT
- int svr_pubkey_allows_agentfwd(void);
-diff --git a/svr-auth.c b/svr-auth.c
-index 64d97aa..1f364ca 100644
---- a/svr-auth.c
-+++ b/svr-auth.c
-@@ -149,10 +149,8 @@ void recv_msg_userauth_request() {
- if (methodlen == AUTH_METHOD_PASSWORD_LEN &&
- strncmp(methodname, AUTH_METHOD_PASSWORD,
- AUTH_METHOD_PASSWORD_LEN) == 0) {
-- if (valid_user) {
-- svr_auth_password();
-- goto out;
-- }
-+ svr_auth_password(valid_user);
-+ goto out;
- }
- }
- #endif
-@@ -164,10 +162,8 @@ void recv_msg_userauth_request() {
- if (methodlen == AUTH_METHOD_PASSWORD_LEN &&
- strncmp(methodname, AUTH_METHOD_PASSWORD,
- AUTH_METHOD_PASSWORD_LEN) == 0) {
-- if (valid_user) {
-- svr_auth_pam();
-- goto out;
-- }
-+ svr_auth_pam(valid_user);
-+ goto out;
- }
- }
- #endif
-@@ -177,12 +173,7 @@ void recv_msg_userauth_request() {
- if (methodlen == AUTH_METHOD_PUBKEY_LEN &&
- strncmp(methodname, AUTH_METHOD_PUBKEY,
- AUTH_METHOD_PUBKEY_LEN) == 0) {
-- if (valid_user) {
-- svr_auth_pubkey();
-- } else {
-- /* pubkey has no failure delay */
-- send_msg_userauth_failure(0, 0);
-- }
-+ svr_auth_pubkey(valid_user);
- goto out;
- }
- #endif
-diff --git a/svr-authpam.c b/svr-authpam.c
-index 05e4f3e..d201bc9 100644
---- a/svr-authpam.c
-+++ b/svr-authpam.c
-@@ -178,13 +178,14 @@ pamConvFunc(int num_msg,
- * Keyboard interactive would be a lot nicer, but since PAM is synchronous, it
- * gets very messy trying to send the interactive challenges, and read the
- * interactive responses, over the network. */
--void svr_auth_pam() {
-+void svr_auth_pam(int valid_user) {
-
- struct UserDataS userData = {NULL, NULL};
- struct pam_conv pamConv = {
- pamConvFunc,
- &userData /* submitted to pamvConvFunc as appdata_ptr */
- };
-+ const char* printable_user = NULL;
-
- pam_handle_t* pamHandlep = NULL;
-
-@@ -204,12 +205,23 @@ void svr_auth_pam() {
-
- password = buf_getstring(ses.payload, &passwordlen);
-
-+ /* We run the PAM conversation regardless of whether the username is valid
-+ in case the conversation function has an inherent delay.
-+ Use ses.authstate.username rather than ses.authstate.pw_name.
-+ After PAM succeeds we then check the valid_user flag too */
-+
- /* used to pass data to the PAM conversation function - don't bother with
- * strdup() etc since these are touched only by our own conversation
- * function (above) which takes care of it */
-- userData.user = ses.authstate.pw_name;
-+ userData.user = ses.authstate.username;
- userData.passwd = password;
-
-+ if (ses.authstate.pw_name) {
-+ printable_user = ses.authstate.pw_name;
-+ } else {
-+ printable_user = "<invalid username>";
-+ }
-+
- /* Init pam */
- if ((rc = pam_start("sshd", NULL, &pamConv, &pamHandlep)) != PAM_SUCCESS) {
- dropbear_log(LOG_WARNING, "pam_start() failed, rc=%d, %s",
-@@ -242,7 +254,7 @@ void svr_auth_pam() {
- rc, pam_strerror(pamHandlep, rc));
- dropbear_log(LOG_WARNING,
- "Bad PAM password attempt for '%s' from %s",
-- ses.authstate.pw_name,
-+ printable_user,
- svr_ses.addrstring);
- send_msg_userauth_failure(0, 1);
- goto cleanup;
-@@ -253,12 +265,18 @@ void svr_auth_pam() {
- rc, pam_strerror(pamHandlep, rc));
- dropbear_log(LOG_WARNING,
- "Bad PAM password attempt for '%s' from %s",
-- ses.authstate.pw_name,
-+ printable_user,
- svr_ses.addrstring);
- send_msg_userauth_failure(0, 1);
- goto cleanup;
- }
-
-+ if (!valid_user) {
-+ /* PAM auth succeeded but the username isn't allowed in for another reason
-+ (checkusername() failed) */
-+ send_msg_userauth_failure(0, 1);
-+ }
-+
- /* successful authentication */
- dropbear_log(LOG_NOTICE, "PAM password auth succeeded for '%s' from %s",
- ses.authstate.pw_name,
-diff --git a/svr-authpasswd.c b/svr-authpasswd.c
-index bdee2aa..69c7d8a 100644
---- a/svr-authpasswd.c
-+++ b/svr-authpasswd.c
-@@ -48,22 +48,14 @@ static int constant_time_strcmp(const char* a, const char* b) {
-
- /* Process a password auth request, sending success or failure messages as
- * appropriate */
--void svr_auth_password() {
-+void svr_auth_password(int valid_user) {
-
- char * passwdcrypt = NULL; /* the crypt from /etc/passwd or /etc/shadow */
- char * testcrypt = NULL; /* crypt generated from the user's password sent */
-- char * password;
-+ char * password = NULL;
- unsigned int passwordlen;
--
- unsigned int changepw;
-
-- passwdcrypt = ses.authstate.pw_passwd;
--
--#ifdef DEBUG_HACKCRYPT
-- /* debugging crypt for non-root testing with shadows */
-- passwdcrypt = DEBUG_HACKCRYPT;
--#endif
--
- /* check if client wants to change password */
- changepw = buf_getbool(ses.payload);
- if (changepw) {
-@@ -73,12 +65,21 @@ void svr_auth_password() {
- }
-
- password = buf_getstring(ses.payload, &passwordlen);
--
-- /* the first bytes of passwdcrypt are the salt */
-- testcrypt = crypt(password, passwdcrypt);
-+ if (valid_user) {
-+ /* the first bytes of passwdcrypt are the salt */
-+ passwdcrypt = ses.authstate.pw_passwd;
-+ testcrypt = crypt(password, passwdcrypt);
-+ }
- m_burn(password, passwordlen);
- m_free(password);
-
-+ /* After we have got the payload contents we can exit if the username
-+ is invalid. Invalid users have already been logged. */
-+ if (!valid_user) {
-+ send_msg_userauth_failure(0, 1);
-+ return;
-+ }
-+
- if (testcrypt == NULL) {
- /* crypt() with an invalid salt like "!!" */
- dropbear_log(LOG_WARNING, "User account '%s' is locked",
-diff --git a/svr-authpubkey.c b/svr-authpubkey.c
-index aa6087c..ff481c8 100644
---- a/svr-authpubkey.c
-+++ b/svr-authpubkey.c
-@@ -79,7 +79,7 @@ static int checkfileperm(char * filename);
-
- /* process a pubkey auth request, sending success or failure message as
- * appropriate */
--void svr_auth_pubkey() {
-+void svr_auth_pubkey(int valid_user) {
-
- unsigned char testkey; /* whether we're just checking if a key is usable */
- char* algo = NULL; /* pubkey algo */
-@@ -102,6 +102,15 @@ void svr_auth_pubkey() {
- keybloblen = buf_getint(ses.payload);
- keyblob = buf_getptr(ses.payload, keybloblen);
-
-+ if (!valid_user) {
-+ /* Return failure once we have read the contents of the packet
-+ required to validate a public key.
-+ Avoids blind user enumeration though it isn't possible to prevent
-+ testing for user existence if the public key is known */
-+ send_msg_userauth_failure(0, 0);
-+ goto out;
-+ }
-+
- /* check if the key is valid */
- if (checkpubkey(algo, algolen, keyblob, keybloblen) == DROPBEAR_FAILURE) {
- send_msg_userauth_failure(0, 0);
