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@@ -1,236 +0,0 @@
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-From 52adbb34c32d3e2e1bcdb941e20a6f81138b8248 Mon Sep 17 00:00:00 2001
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-From: Matt Johnston <matt@ucc.asn.au>
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-Date: Thu, 23 Aug 2018 23:43:12 +0800
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-Subject: [PATCH] Wait to fail invalid usernames
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-
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-[hg: https://secure.ucc.asn.au/hg/dropbear/rev/5d2d1021ca00]
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-Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
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----
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- auth.h | 6 +++---
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- svr-auth.c | 19 +++++--------------
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- svr-authpam.c | 26 ++++++++++++++++++++++----
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- svr-authpasswd.c | 27 ++++++++++++++-------------
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- svr-authpubkey.c | 11 ++++++++++-
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- 5 files changed, 54 insertions(+), 35 deletions(-)
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-
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-diff --git a/auth.h b/auth.h
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-index da498f5..98f5468 100644
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---- a/auth.h
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-+++ b/auth.h
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-@@ -37,9 +37,9 @@ void recv_msg_userauth_request(void);
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- void send_msg_userauth_failure(int partial, int incrfail);
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- void send_msg_userauth_success(void);
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- void send_msg_userauth_banner(const buffer *msg);
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--void svr_auth_password(void);
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--void svr_auth_pubkey(void);
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--void svr_auth_pam(void);
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-+void svr_auth_password(int valid_user);
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-+void svr_auth_pubkey(int valid_user);
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-+void svr_auth_pam(int valid_user);
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-
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- #if DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT
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- int svr_pubkey_allows_agentfwd(void);
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-diff --git a/svr-auth.c b/svr-auth.c
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-index c19c090..edde86b 100644
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---- a/svr-auth.c
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-+++ b/svr-auth.c
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-@@ -149,10 +149,8 @@ void recv_msg_userauth_request() {
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- if (methodlen == AUTH_METHOD_PASSWORD_LEN &&
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- strncmp(methodname, AUTH_METHOD_PASSWORD,
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- AUTH_METHOD_PASSWORD_LEN) == 0) {
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-- if (valid_user) {
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-- svr_auth_password();
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-- goto out;
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-- }
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-+ svr_auth_password(valid_user);
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-+ goto out;
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- }
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- }
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- #endif
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-@@ -164,10 +162,8 @@ void recv_msg_userauth_request() {
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- if (methodlen == AUTH_METHOD_PASSWORD_LEN &&
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- strncmp(methodname, AUTH_METHOD_PASSWORD,
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- AUTH_METHOD_PASSWORD_LEN) == 0) {
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-- if (valid_user) {
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-- svr_auth_pam();
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-- goto out;
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-- }
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-+ svr_auth_pam(valid_user);
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-+ goto out;
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- }
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- }
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- #endif
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-@@ -177,12 +173,7 @@ void recv_msg_userauth_request() {
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- if (methodlen == AUTH_METHOD_PUBKEY_LEN &&
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- strncmp(methodname, AUTH_METHOD_PUBKEY,
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- AUTH_METHOD_PUBKEY_LEN) == 0) {
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-- if (valid_user) {
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-- svr_auth_pubkey();
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-- } else {
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-- /* pubkey has no failure delay */
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-- send_msg_userauth_failure(0, 0);
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-- }
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-+ svr_auth_pubkey(valid_user);
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- goto out;
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- }
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- #endif
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-diff --git a/svr-authpam.c b/svr-authpam.c
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-index 05e4f3e..d201bc9 100644
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---- a/svr-authpam.c
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-+++ b/svr-authpam.c
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-@@ -178,13 +178,14 @@ pamConvFunc(int num_msg,
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- * Keyboard interactive would be a lot nicer, but since PAM is synchronous, it
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- * gets very messy trying to send the interactive challenges, and read the
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- * interactive responses, over the network. */
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--void svr_auth_pam() {
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-+void svr_auth_pam(int valid_user) {
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-
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- struct UserDataS userData = {NULL, NULL};
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- struct pam_conv pamConv = {
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- pamConvFunc,
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- &userData /* submitted to pamvConvFunc as appdata_ptr */
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- };
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-+ const char* printable_user = NULL;
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-
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- pam_handle_t* pamHandlep = NULL;
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-
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-@@ -204,12 +205,23 @@ void svr_auth_pam() {
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-
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- password = buf_getstring(ses.payload, &passwordlen);
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-
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-+ /* We run the PAM conversation regardless of whether the username is valid
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-+ in case the conversation function has an inherent delay.
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-+ Use ses.authstate.username rather than ses.authstate.pw_name.
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-+ After PAM succeeds we then check the valid_user flag too */
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-+
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- /* used to pass data to the PAM conversation function - don't bother with
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- * strdup() etc since these are touched only by our own conversation
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- * function (above) which takes care of it */
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-- userData.user = ses.authstate.pw_name;
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-+ userData.user = ses.authstate.username;
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- userData.passwd = password;
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-
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-+ if (ses.authstate.pw_name) {
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-+ printable_user = ses.authstate.pw_name;
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-+ } else {
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-+ printable_user = "<invalid username>";
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-+ }
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-+
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- /* Init pam */
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- if ((rc = pam_start("sshd", NULL, &pamConv, &pamHandlep)) != PAM_SUCCESS) {
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- dropbear_log(LOG_WARNING, "pam_start() failed, rc=%d, %s",
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-@@ -242,7 +254,7 @@ void svr_auth_pam() {
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- rc, pam_strerror(pamHandlep, rc));
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- dropbear_log(LOG_WARNING,
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- "Bad PAM password attempt for '%s' from %s",
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-- ses.authstate.pw_name,
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-+ printable_user,
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- svr_ses.addrstring);
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- send_msg_userauth_failure(0, 1);
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- goto cleanup;
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-@@ -253,12 +265,18 @@ void svr_auth_pam() {
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- rc, pam_strerror(pamHandlep, rc));
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- dropbear_log(LOG_WARNING,
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- "Bad PAM password attempt for '%s' from %s",
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-- ses.authstate.pw_name,
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-+ printable_user,
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- svr_ses.addrstring);
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- send_msg_userauth_failure(0, 1);
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- goto cleanup;
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- }
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-
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-+ if (!valid_user) {
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-+ /* PAM auth succeeded but the username isn't allowed in for another reason
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-+ (checkusername() failed) */
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-+ send_msg_userauth_failure(0, 1);
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-+ }
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-+
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- /* successful authentication */
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- dropbear_log(LOG_NOTICE, "PAM password auth succeeded for '%s' from %s",
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- ses.authstate.pw_name,
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-diff --git a/svr-authpasswd.c b/svr-authpasswd.c
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-index bdee2aa..69c7d8a 100644
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---- a/svr-authpasswd.c
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-+++ b/svr-authpasswd.c
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-@@ -48,22 +48,14 @@ static int constant_time_strcmp(const char* a, const char* b) {
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-
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- /* Process a password auth request, sending success or failure messages as
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- * appropriate */
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--void svr_auth_password() {
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-+void svr_auth_password(int valid_user) {
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-
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- char * passwdcrypt = NULL; /* the crypt from /etc/passwd or /etc/shadow */
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- char * testcrypt = NULL; /* crypt generated from the user's password sent */
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-- char * password;
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-+ char * password = NULL;
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- unsigned int passwordlen;
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--
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- unsigned int changepw;
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-
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-- passwdcrypt = ses.authstate.pw_passwd;
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--
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--#ifdef DEBUG_HACKCRYPT
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-- /* debugging crypt for non-root testing with shadows */
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-- passwdcrypt = DEBUG_HACKCRYPT;
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--#endif
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--
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- /* check if client wants to change password */
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- changepw = buf_getbool(ses.payload);
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- if (changepw) {
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-@@ -73,12 +65,21 @@ void svr_auth_password() {
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- }
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-
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- password = buf_getstring(ses.payload, &passwordlen);
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--
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-- /* the first bytes of passwdcrypt are the salt */
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-- testcrypt = crypt(password, passwdcrypt);
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-+ if (valid_user) {
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-+ /* the first bytes of passwdcrypt are the salt */
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-+ passwdcrypt = ses.authstate.pw_passwd;
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-+ testcrypt = crypt(password, passwdcrypt);
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-+ }
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- m_burn(password, passwordlen);
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- m_free(password);
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-
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-+ /* After we have got the payload contents we can exit if the username
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-+ is invalid. Invalid users have already been logged. */
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-+ if (!valid_user) {
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-+ send_msg_userauth_failure(0, 1);
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-+ return;
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-+ }
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-+
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- if (testcrypt == NULL) {
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- /* crypt() with an invalid salt like "!!" */
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- dropbear_log(LOG_WARNING, "User account '%s' is locked",
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-diff --git a/svr-authpubkey.c b/svr-authpubkey.c
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-index aa6087c..ff481c8 100644
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---- a/svr-authpubkey.c
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-+++ b/svr-authpubkey.c
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-@@ -79,7 +79,7 @@ static int checkfileperm(char * filename);
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-
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- /* process a pubkey auth request, sending success or failure message as
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- * appropriate */
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--void svr_auth_pubkey() {
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-+void svr_auth_pubkey(int valid_user) {
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-
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- unsigned char testkey; /* whether we're just checking if a key is usable */
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- char* algo = NULL; /* pubkey algo */
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-@@ -102,6 +102,15 @@ void svr_auth_pubkey() {
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- keybloblen = buf_getint(ses.payload);
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- keyblob = buf_getptr(ses.payload, keybloblen);
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-
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-+ if (!valid_user) {
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-+ /* Return failure once we have read the contents of the packet
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-+ required to validate a public key.
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-+ Avoids blind user enumeration though it isn't possible to prevent
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-+ testing for user existence if the public key is known */
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-+ send_msg_userauth_failure(0, 0);
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-+ goto out;
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-+ }
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-+
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- /* check if the key is valid */
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- if (checkpubkey(algo, algolen, keyblob, keybloblen) == DROPBEAR_FAILURE) {
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- send_msg_userauth_failure(0, 0);
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---
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-2.11.0
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-
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Peter Korsgaard