commit 207e329423042543c7877832acb05d27c44629aa Author: Juergen Daubert <jue@jue.li> Date: Fri Aug 31 16:29:36 2018 +0200 dropbear: add patch diff --git a/dropbear/CVE-2018-15599.diff b/dropbear/CVE-2018-15599.diff new file mode 100644 index 000000000..963ed35bb --- /dev/null +++ b/dropbear/CVE-2018-15599.diff @@ -0,0 +1,222 @@ + +# HG changeset patch +# User Matt Johnston <matt@ucc.asn.au> +# Date 1535038992 -28800 +# Node ID 5d2d1021ca0006337af58859c861f2349715b73b +# Parent cd23631dab5c653c66fe697e24f026aefbfcecb3 +Wait to fail invalid usernames + +diff -r cd23631dab5c -r 5d2d1021ca00 auth.h +--- a/auth.h Thu Aug 23 22:10:07 2018 +0800 ++++ b/auth.h Thu Aug 23 23:43:12 2018 +0800 +@@ -37,9 +37,9 @@ + 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 -r cd23631dab5c -r 5d2d1021ca00 svr-auth.c +--- a/svr-auth.c Thu Aug 23 22:10:07 2018 +0800 ++++ b/svr-auth.c Thu Aug 23 23:43:12 2018 +0800 +@@ -149,10 +149,8 @@ + 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 @@ + 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 @@ + 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 -r cd23631dab5c -r 5d2d1021ca00 svr-authpam.c +--- a/svr-authpam.c Thu Aug 23 22:10:07 2018 +0800 ++++ b/svr-authpam.c Thu Aug 23 23:43:12 2018 +0800 +@@ -178,13 +178,14 @@ + * 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 @@ + + 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 @@ + 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 @@ + 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 -r cd23631dab5c -r 5d2d1021ca00 svr-authpasswd.c +--- a/svr-authpasswd.c Thu Aug 23 22:10:07 2018 +0800 ++++ b/svr-authpasswd.c Thu Aug 23 23:43:12 2018 +0800 +@@ -48,22 +48,14 @@ + + /* 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 @@ + } + + 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 -r cd23631dab5c -r 5d2d1021ca00 svr-authpubkey.c +--- a/svr-authpubkey.c Thu Aug 23 22:10:07 2018 +0800 ++++ b/svr-authpubkey.c Thu Aug 23 23:43:12 2018 +0800 +@@ -79,7 +79,7 @@ + + /* 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 @@ + 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); +