From f017715120b67ff02f56ed5db131436ee62aeffb Mon Sep 17 00:00:00 2001 From: Mingli Yu Date: Thu, 6 Sep 2018 16:06:33 +0800 Subject: dropbear: Fix CVE-2018-15599 Wait to fail invalid usernames to fix CVE-2018-15599 Rework 0006-dropbear-configuration-file.patch to fix fuzz warnings Signed-off-by: Mingli Yu Signed-off-by: Richard Purdie --- meta/recipes-core/dropbear/dropbear.inc | 1 + .../0006-dropbear-configuration-file.patch | 23 +- .../dropbear/dropbear/CVE-2018-15599.patch | 236 +++++++++++++++++++++ 3 files changed, 254 insertions(+), 6 deletions(-) create mode 100644 meta/recipes-core/dropbear/dropbear/CVE-2018-15599.patch diff --git a/meta/recipes-core/dropbear/dropbear.inc b/meta/recipes-core/dropbear/dropbear.inc index b634e0e53e..dc24ea71bf 100644 --- a/meta/recipes-core/dropbear/dropbear.inc +++ b/meta/recipes-core/dropbear/dropbear.inc @@ -13,6 +13,7 @@ RPROVIDES_${PN} = "ssh sshd" DEPENDS += "${@bb.utils.contains('DISTRO_FEATURES', 'pam', 'libpam', '', d)}" SRC_URI = "http://matt.ucc.asn.au/dropbear/releases/dropbear-${PV}.tar.bz2 \ + file://CVE-2018-15599.patch \ file://0001-urandom-xauth-changes-to-options.h.patch \ file://0007-fix-localoptions-search-path.patch \ file://init \ diff --git a/meta/recipes-core/dropbear/dropbear/0006-dropbear-configuration-file.patch b/meta/recipes-core/dropbear/dropbear/0006-dropbear-configuration-file.patch index fa4c8d0a67..deed78ffb9 100644 --- a/meta/recipes-core/dropbear/dropbear/0006-dropbear-configuration-file.patch +++ b/meta/recipes-core/dropbear/dropbear/0006-dropbear-configuration-file.patch @@ -1,4 +1,7 @@ -Subject: [PATCH 6/6] dropbear configuration file +From e3a5db1b6d3f6382a15b2266458c26c645a10f18 Mon Sep 17 00:00:00 2001 +From: Mingli Yu +Date: Thu, 6 Sep 2018 15:54:00 +0800 +Subject: [PATCH] dropbear configuration file dropbear: Change the path ("/etc/pam.d/sshd" as default) to find a pam configuration file \ to "/etc/pam.d/dropbear for dropbear when enabling pam supporting" @@ -7,12 +10,17 @@ Upstream-Status: Inappropriate [configuration] Signed-off-by: Maxin B. John Signed-off-by: Xiaofeng Yan +Signed-off-by: Mingli Yu --- -diff -Naur dropbear-2013.60-orig/svr-authpam.c dropbear-2013.60/svr-authpam.c ---- dropbear-2013.60-orig/svr-authpam.c 2013-10-16 16:34:53.000000000 +0200 -+++ dropbear-2013.60/svr-authpam.c 2013-10-21 17:04:04.969416055 +0200 -@@ -211,7 +211,7 @@ - userData.passwd = password; + svr-authpam.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/svr-authpam.c b/svr-authpam.c +index d201bc9..165ec5c 100644 +--- a/svr-authpam.c ++++ b/svr-authpam.c +@@ -223,7 +223,7 @@ void svr_auth_pam(int valid_user) { + } /* Init pam */ - if ((rc = pam_start("sshd", NULL, &pamConv, &pamHandlep)) != PAM_SUCCESS) { @@ -20,3 +28,6 @@ diff -Naur dropbear-2013.60-orig/svr-authpam.c dropbear-2013.60/svr-authpam.c dropbear_log(LOG_WARNING, "pam_start() failed, rc=%d, %s", rc, pam_strerror(pamHandlep, rc)); goto cleanup; +-- +2.7.4 + diff --git a/meta/recipes-core/dropbear/dropbear/CVE-2018-15599.patch b/meta/recipes-core/dropbear/dropbear/CVE-2018-15599.patch new file mode 100644 index 0000000000..912545c957 --- /dev/null +++ b/meta/recipes-core/dropbear/dropbear/CVE-2018-15599.patch @@ -0,0 +1,236 @@ +From 256e2abb8150f9fea33cd026597dbe70f0379296 Mon Sep 17 00:00:00 2001 +From: Matt Johnston +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 +--- + 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 = ""; ++ } ++ + /* 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); -- cgit 1.2.3-korg