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gnu: dropbear: Update to 2019.77.
gnu: dropbear: Update to 2019.77.
* gnu/packages/ssh.scm (dropbear): Update to 2019.77. [source]: Remove patch. * gnu/packages/patches/dropbear-CVE-2018-15599.patch: Delete file. * gnu/local.mk (dist_patch_DATA): Remove it.version-1.0.0
Tobias Geerinckx-Rice
3 years ago
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GPG Key ID: DB0FF884F556D79
3 changed files with 10 additions and 252 deletions
@ -1,240 +0,0 @@ |
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Fix CVE-2018-15599: |
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|
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http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002108.html |
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https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-15599 |
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Patch copied from upstream source repository: |
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https://github.com/mkj/dropbear/commit/52adbb34c32d3e2e1bcdb941e20a6f81138b8248 |
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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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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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diff --git a/auth.h b/auth.h
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index da498f5b..98f54683 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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#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 c19c0901..edde86bc 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 05e4f3e5..d201bc96 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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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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pam_handle_t* pamHandlep = NULL; |
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@@ -204,12 +205,23 @@ void svr_auth_pam() {
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password = buf_getstring(ses.payload, &passwordlen); |
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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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+ 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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+ 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 bdee2aa1..69c7d8af 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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/* 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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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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- 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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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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+ /* 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 aa6087c9..ff481c87 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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/* 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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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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+ 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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