Description: Handle SELinux authorisation roles Rejected upstream due to discomfort with magic usernames; a better approach will need an SSH protocol change. In the meantime, this came from Debian's SELinux maintainer, so we'll keep it until we have something better. Author: Manoj Srivastava Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1641 Bug-Debian: http://bugs.debian.org/394795 Last-Update: 2013-05-07 Index: b/auth.h =================================================================== --- a/auth.h +++ b/auth.h @@ -59,6 +59,7 @@ char *service; struct passwd *pw; /* set if 'valid' */ char *style; + char *role; void *kbdintctxt; void *jpake_ctx; #ifdef BSD_AUTH Index: b/auth1.c =================================================================== --- a/auth1.c +++ b/auth1.c @@ -385,7 +385,7 @@ do_authentication(Authctxt *authctxt) { u_int ulen; - char *user, *style = NULL; + char *user, *style = NULL, *role = NULL; /* Get the name of the user that we wish to log in as. */ packet_read_expect(SSH_CMSG_USER); @@ -394,11 +394,17 @@ user = packet_get_cstring(&ulen); packet_check_eom(); + if ((role = strchr(user, '/')) != NULL) + *role++ = '\0'; + if ((style = strchr(user, ':')) != NULL) *style++ = '\0'; + else if (role && (style = strchr(role, ':')) != NULL) + *style++ = '\0'; authctxt->user = user; authctxt->style = style; + authctxt->role = role; /* Verify that the user is a valid user. */ if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL) Index: b/auth2.c =================================================================== --- a/auth2.c +++ b/auth2.c @@ -219,7 +219,7 @@ { Authctxt *authctxt = ctxt; Authmethod *m = NULL; - char *user, *service, *method, *style = NULL; + char *user, *service, *method, *style = NULL, *role = NULL; int authenticated = 0; if (authctxt == NULL) @@ -231,8 +231,13 @@ debug("userauth-request for user %s service %s method %s", user, service, method); debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); + if ((role = strchr(user, '/')) != NULL) + *role++ = 0; + if ((style = strchr(user, ':')) != NULL) *style++ = 0; + else if (role && (style = strchr(role, ':')) != NULL) + *style++ = '\0'; if (authctxt->attempt++ == 0) { /* setup auth context */ @@ -256,8 +261,9 @@ use_privsep ? " [net]" : ""); authctxt->service = xstrdup(service); authctxt->style = style ? xstrdup(style) : NULL; + authctxt->role = role ? xstrdup(role) : NULL; if (use_privsep) - mm_inform_authserv(service, style); + mm_inform_authserv(service, style, role); userauth_banner(); if (auth2_setup_methods_lists(authctxt) != 0) packet_disconnect("no authentication methods enabled"); Index: b/monitor.c =================================================================== --- a/monitor.c +++ b/monitor.c @@ -145,6 +145,7 @@ int mm_answer_pwnamallow(int, Buffer *); int mm_answer_auth2_read_banner(int, Buffer *); int mm_answer_authserv(int, Buffer *); +int mm_answer_authrole(int, Buffer *); int mm_answer_authpassword(int, Buffer *); int mm_answer_bsdauthquery(int, Buffer *); int mm_answer_bsdauthrespond(int, Buffer *); @@ -226,6 +227,7 @@ {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, + {MONITOR_REQ_AUTHROLE, MON_ONCE, mm_answer_authrole}, {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, #ifdef USE_PAM @@ -837,6 +839,7 @@ else { /* Allow service/style information on the auth context */ monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); + monitor_permit(mon_dispatch, MONITOR_REQ_AUTHROLE, 1); monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); } #ifdef USE_PAM @@ -869,14 +872,37 @@ authctxt->service = buffer_get_string(m, NULL); authctxt->style = buffer_get_string(m, NULL); - debug3("%s: service=%s, style=%s", - __func__, authctxt->service, authctxt->style); + authctxt->role = buffer_get_string(m, NULL); + debug3("%s: service=%s, style=%s, role=%s", + __func__, authctxt->service, authctxt->style, authctxt->role); if (strlen(authctxt->style) == 0) { xfree(authctxt->style); authctxt->style = NULL; } + if (strlen(authctxt->role) == 0) { + xfree(authctxt->role); + authctxt->role = NULL; + } + + return (0); +} + +int +mm_answer_authrole(int sock, Buffer *m) +{ + monitor_permit_authentications(1); + + authctxt->role = buffer_get_string(m, NULL); + debug3("%s: role=%s", + __func__, authctxt->role); + + if (strlen(authctxt->role) == 0) { + xfree(authctxt->role); + authctxt->role = NULL; + } + return (0); } @@ -1471,7 +1497,7 @@ res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); if (res == 0) goto error; - pty_setowner(authctxt->pw, s->tty); + pty_setowner(authctxt->pw, s->tty, authctxt->role); buffer_put_int(m, 1); buffer_put_cstring(m, s->tty); Index: b/monitor.h =================================================================== --- a/monitor.h +++ b/monitor.h @@ -73,6 +73,8 @@ MONITOR_REQ_GSSSIGN = 200, MONITOR_ANS_GSSSIGN = 201, MONITOR_REQ_GSSUPCREDS = 202, MONITOR_ANS_GSSUPCREDS = 203, + MONITOR_REQ_AUTHROLE = 300, + }; struct mm_master; Index: b/monitor_wrap.c =================================================================== --- a/monitor_wrap.c +++ b/monitor_wrap.c @@ -318,10 +318,10 @@ return (banner); } -/* Inform the privileged process about service and style */ +/* Inform the privileged process about service, style, and role */ void -mm_inform_authserv(char *service, char *style) +mm_inform_authserv(char *service, char *style, char *role) { Buffer m; @@ -330,11 +330,29 @@ buffer_init(&m); buffer_put_cstring(&m, service); buffer_put_cstring(&m, style ? style : ""); + buffer_put_cstring(&m, role ? role : ""); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, &m); buffer_free(&m); } + +/* Inform the privileged process about role */ + +void +mm_inform_authrole(char *role) +{ + Buffer m; + + debug3("%s entering", __func__); + + buffer_init(&m); + buffer_put_cstring(&m, role ? role : ""); + + mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHROLE, &m); + + buffer_free(&m); +} /* Do the password authentication */ int Index: b/monitor_wrap.h =================================================================== --- a/monitor_wrap.h +++ b/monitor_wrap.h @@ -41,7 +41,8 @@ int mm_is_monitor(void); DH *mm_choose_dh(int, int, int); int mm_key_sign(Key *, u_char **, u_int *, u_char *, u_int); -void mm_inform_authserv(char *, char *); +void mm_inform_authserv(char *, char *, char *); +void mm_inform_authrole(char *); struct passwd *mm_getpwnamallow(const char *); char *mm_auth2_read_banner(void); int mm_auth_password(struct Authctxt *, char *); Index: b/openbsd-compat/port-linux.c =================================================================== --- a/openbsd-compat/port-linux.c +++ b/openbsd-compat/port-linux.c @@ -29,6 +29,12 @@ #include #include +#ifdef WITH_SELINUX +#include "key.h" +#include "hostfile.h" +#include "auth.h" +#endif + #include "log.h" #include "xmalloc.h" #include "port-linux.h" @@ -58,7 +64,7 @@ /* Return the default security context for the given username */ static security_context_t -ssh_selinux_getctxbyname(char *pwname) +ssh_selinux_getctxbyname(char *pwname, const char *role) { security_context_t sc = NULL; char *sename = NULL, *lvl = NULL; @@ -73,9 +79,16 @@ #endif #ifdef HAVE_GET_DEFAULT_CONTEXT_WITH_LEVEL - r = get_default_context_with_level(sename, lvl, NULL, &sc); + if (role != NULL && role[0]) + r = get_default_context_with_rolelevel(sename, role, lvl, NULL, + &sc); + else + r = get_default_context_with_level(sename, lvl, NULL, &sc); #else - r = get_default_context(sename, NULL, &sc); + if (role != NULL && role[0]) + r = get_default_context_with_role(sename, role, NULL, &sc); + else + r = get_default_context(sename, NULL, &sc); #endif if (r != 0) { @@ -107,7 +120,7 @@ /* Set the execution context to the default for the specified user */ void -ssh_selinux_setup_exec_context(char *pwname) +ssh_selinux_setup_exec_context(char *pwname, const char *role) { security_context_t user_ctx = NULL; @@ -116,7 +129,7 @@ debug3("%s: setting execution context", __func__); - user_ctx = ssh_selinux_getctxbyname(pwname); + user_ctx = ssh_selinux_getctxbyname(pwname, role); if (setexeccon(user_ctx) != 0) { switch (security_getenforce()) { case -1: @@ -138,7 +151,7 @@ /* Set the TTY context for the specified user */ void -ssh_selinux_setup_pty(char *pwname, const char *tty) +ssh_selinux_setup_pty(char *pwname, const char *tty, const char *role) { security_context_t new_tty_ctx = NULL; security_context_t user_ctx = NULL; @@ -149,7 +162,7 @@ debug3("%s: setting TTY context on %s", __func__, tty); - user_ctx = ssh_selinux_getctxbyname(pwname); + user_ctx = ssh_selinux_getctxbyname(pwname, role); /* XXX: should these calls fatal() upon failure in enforcing mode? */ Index: b/openbsd-compat/port-linux.h =================================================================== --- a/openbsd-compat/port-linux.h +++ b/openbsd-compat/port-linux.h @@ -21,8 +21,8 @@ #ifdef WITH_SELINUX int ssh_selinux_enabled(void); -void ssh_selinux_setup_pty(char *, const char *); -void ssh_selinux_setup_exec_context(char *); +void ssh_selinux_setup_pty(char *, const char *, const char *); +void ssh_selinux_setup_exec_context(char *, const char *); void ssh_selinux_change_context(const char *); void ssh_selinux_setfscreatecon(const char *); #endif Index: b/platform.c =================================================================== --- a/platform.c +++ b/platform.c @@ -134,7 +134,7 @@ * called if sshd is running as root. */ void -platform_setusercontext_post_groups(struct passwd *pw) +platform_setusercontext_post_groups(struct passwd *pw, const char *role) { #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM) /* @@ -181,7 +181,7 @@ } #endif /* HAVE_SETPCRED */ #ifdef WITH_SELINUX - ssh_selinux_setup_exec_context(pw->pw_name); + ssh_selinux_setup_exec_context(pw->pw_name, role); #endif } Index: b/platform.h =================================================================== --- a/platform.h +++ b/platform.h @@ -26,7 +26,7 @@ void platform_post_fork_child(void); int platform_privileged_uidswap(void); void platform_setusercontext(struct passwd *); -void platform_setusercontext_post_groups(struct passwd *); +void platform_setusercontext_post_groups(struct passwd *, const char *); char *platform_get_krb5_client(const char *); char *platform_krb5_get_principal_name(const char *); int platform_sys_dir_uid(uid_t); Index: b/session.c =================================================================== --- a/session.c +++ b/session.c @@ -1474,7 +1474,7 @@ /* Set login name, uid, gid, and groups. */ void -do_setusercontext(struct passwd *pw) +do_setusercontext(struct passwd *pw, const char *role) { char *chroot_path, *tmp; @@ -1502,7 +1502,7 @@ endgrent(); #endif - platform_setusercontext_post_groups(pw); + platform_setusercontext_post_groups(pw, role); if (options.chroot_directory != NULL && strcasecmp(options.chroot_directory, "none") != 0) { @@ -1633,7 +1633,7 @@ /* Force a password change */ if (s->authctxt->force_pwchange) { - do_setusercontext(pw); + do_setusercontext(pw, s->authctxt->role); child_close_fds(); do_pwchange(s); exit(1); @@ -1660,7 +1660,7 @@ /* When PAM is enabled we rely on it to do the nologin check */ if (!options.use_pam) do_nologin(pw); - do_setusercontext(pw); + do_setusercontext(pw, s->authctxt->role); /* * PAM session modules in do_setusercontext may have * generated messages, so if this in an interactive @@ -2072,7 +2072,7 @@ tty_parse_modes(s->ttyfd, &n_bytes); if (!use_privsep) - pty_setowner(s->pw, s->tty); + pty_setowner(s->pw, s->tty, s->authctxt->role); /* Set window size from the packet. */ pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); Index: b/session.h =================================================================== --- a/session.h +++ b/session.h @@ -76,7 +76,7 @@ Session *session_new(void); Session *session_by_tty(char *); void session_close(Session *); -void do_setusercontext(struct passwd *); +void do_setusercontext(struct passwd *, const char *); void child_set_env(char ***envp, u_int *envsizep, const char *name, const char *value); Index: b/sshd.c =================================================================== --- a/sshd.c +++ b/sshd.c @@ -745,7 +745,7 @@ RAND_seed(rnd, sizeof(rnd)); /* Drop privileges */ - do_setusercontext(authctxt->pw); + do_setusercontext(authctxt->pw, authctxt->role); skip: /* It is safe now to apply the key state */ Index: b/sshpty.c =================================================================== --- a/sshpty.c +++ b/sshpty.c @@ -200,7 +200,7 @@ } void -pty_setowner(struct passwd *pw, const char *tty) +pty_setowner(struct passwd *pw, const char *tty, const char *role) { struct group *grp; gid_t gid; @@ -227,7 +227,7 @@ strerror(errno)); #ifdef WITH_SELINUX - ssh_selinux_setup_pty(pw->pw_name, tty); + ssh_selinux_setup_pty(pw->pw_name, tty, role); #endif if (st.st_uid != pw->pw_uid || st.st_gid != gid) { Index: b/sshpty.h =================================================================== --- a/sshpty.h +++ b/sshpty.h @@ -24,4 +24,4 @@ void pty_release(const char *); void pty_make_controlling_tty(int *, const char *); void pty_change_window_size(int, u_int, u_int, u_int, u_int); -void pty_setowner(struct passwd *, const char *); +void pty_setowner(struct passwd *, const char *, const char *);