4 files changed, 62 insertions, 11 deletions

diff --git a/servconf.c b/servconf.c
index cb5786583..a41fdc26a 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1,5 +1,5 @@
 
-/* $OpenBSD: servconf.c,v 1.333 2018/06/19 02:59:41 djm Exp $ */
+/* $OpenBSD: servconf.c,v 1.334 2018/07/03 10:59:35 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -130,6 +130,7 @@ initialize_server_options(ServerOptions *options)
         options->challenge_response_authentication = -1;
         options->permit_empty_passwd = -1;
         options->permit_user_env = -1;
+        options->permit_user_env_whitelist = NULL;
         options->compression = -1;
         options->rekey_limit = -1;
         options->rekey_interval = -1;
@@ -329,8 +330,10 @@ fill_default_server_options(ServerOptions *options)
                 options->challenge_response_authentication = 1;
         if (options->permit_empty_passwd == -1)
                 options->permit_empty_passwd = 0;
-        if (options->permit_user_env == -1)
+        if (options->permit_user_env == -1) {
                 options->permit_user_env = 0;
+                options->permit_user_env_whitelist = NULL;
+        }
         if (options->compression == -1)
                 options->compression = COMP_DELAYED;
         if (options->rekey_limit == -1)
@@ -1514,7 +1517,29 @@ process_server_config_line(ServerOptions *options, char *line,
 
         case sPermitUserEnvironment:
                 intptr = &options->permit_user_env;
-                goto parse_flag;
+                charptr = &options->permit_user_env_whitelist;
+                arg = strdelim(&cp);
+                if (!arg || *arg == '\0')
+                        fatal("%s line %d: missing argument.",
+                            filename, linenum);
+                value = 0;
+                p = NULL;
+                if (strcmp(arg, "yes") == 0)
+                        value = 1;
+                else if (strcmp(arg, "no") == 0)
+                        value = 0;
+                else {
+                        /* Pattern-list specified */
+                        value = 1;
+                        p = xstrdup(arg);
+                }
+                if (*activep && *intptr == -1) {
+                        *intptr = value;
+                        *charptr = p;
+                        p = NULL;
+                }
+                free(p);
+                break;
 
         case sCompression:
                 intptr = &options->compression;
@@ -2528,7 +2553,6 @@ dump_config(ServerOptions *o)
         dump_cfg_fmtint(sStrictModes, o->strict_modes);
         dump_cfg_fmtint(sTCPKeepAlive, o->tcp_keep_alive);
         dump_cfg_fmtint(sEmptyPasswd, o->permit_empty_passwd);
-        dump_cfg_fmtint(sPermitUserEnvironment, o->permit_user_env);
         dump_cfg_fmtint(sCompression, o->compression);
         dump_cfg_fmtint(sGatewayPorts, o->fwd_opts.gateway_ports);
         dump_cfg_fmtint(sUseDNS, o->use_dns);
@@ -2628,4 +2652,12 @@ dump_config(ServerOptions *o)
                         printf(" %s", o->permitted_listens[i]);
         }
         printf("\n");
+
+        if (o->permit_user_env_whitelist == NULL) {
+                dump_cfg_fmtint(sPermitUserEnvironment, o->permit_user_env);
+        } else {
+                printf("permituserenvironment %s\n",
+                    o->permit_user_env_whitelist);
+        }
+
 }
diff --git a/servconf.h b/servconf.h
index db8362c60..73327135b 100644
--- a/servconf.h
+++ b/servconf.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: servconf.h,v 1.134 2018/06/09 03:03:10 djm Exp $ */
+/* $OpenBSD: servconf.h,v 1.135 2018/07/03 10:59:35 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -133,6 +133,7 @@ typedef struct {
         int     permit_empty_passwd;    /* If false, do not permit empty
                                          * passwords. */
         int     permit_user_env;        /* If true, read ~/.ssh/environment */
+        char   *permit_user_env_whitelist; /* pattern-list whitelist */
         int     compression;    /* If true, compression is allowed */
         int     allow_tcp_forwarding; /* One of FORWARD_* */
         int     allow_streamlocal_forwarding; /* One of FORWARD_* */
@@ -242,6 +243,7 @@ struct connection_info {
                 M_CP_STROPT(hostbased_key_types); \
                 M_CP_STROPT(pubkey_key_types); \
                 M_CP_STROPT(routing_domain); \
+                M_CP_STROPT(permit_user_env_whitelist); \
                 M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
                 M_CP_STRARRAYOPT(allow_users, num_allow_users); \
                 M_CP_STRARRAYOPT(deny_users, num_deny_users); \
diff --git a/session.c b/session.c
index 85df6a272..3c4e9c440 100644
--- a/session.c
+++ b/session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.300 2018/06/09 03:03:10 djm Exp $ */
+/* $OpenBSD: session.c,v 1.301 2018/07/03 10:59:35 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -867,10 +867,12 @@ check_quietlogin(Session *s, const char *command)
  * into the environment.  If the file does not exist, this does nothing.
  * Otherwise, it must consist of empty lines, comments (line starts with '#')
  * and assignments of the form name=value.  No other forms are allowed.
+ * If whitelist is not NULL, then it is interpreted as a pattern list and
+ * only variable names that match it will be accepted.
  */
 static void
 read_environment_file(char ***env, u_int *envsize,
-        const char *filename)
+        const char *filename, const char *whitelist)
 {
         FILE *f;
         char *line = NULL, *cp, *value;
@@ -903,6 +905,9 @@ read_environment_file(char ***env, u_int *envsize,
                  */
                 *value = '\0';
                 value++;
+                if (whitelist != NULL &&
+                    match_pattern_list(cp, whitelist, 0) != 1)
+                        continue;
                 child_set_env(env, envsize, cp, value);
         }
         free(line);
@@ -1121,7 +1126,12 @@ do_setup_env(struct ssh *ssh, Session *s, const char *shell)
                         cp = strchr(ocp, '=');
                         if (*cp == '=') {
                                 *cp = '\0';
-                                child_set_env(&env, &envsize, ocp, cp + 1);
+                                /* Apply PermitUserEnvironment whitelist */
+                                if (options.permit_user_env_whitelist == NULL ||
+                                    match_pattern_list(ocp,
+                                    options.permit_user_env_whitelist, 0) == 1)
+                                        child_set_env(&env, &envsize,
+                                            ocp, cp + 1);
                         }
                         free(ocp);
                 }
@@ -1131,7 +1141,8 @@ do_setup_env(struct ssh *ssh, Session *s, const char *shell)
         if (options.permit_user_env) {
                 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
                     pw->pw_dir);
-                read_environment_file(&env, &envsize, buf);
+                read_environment_file(&env, &envsize, buf,
+                    options.permit_user_env_whitelist);
         }
 
 #ifdef USE_PAM
diff --git a/sshd_config.5 b/sshd_config.5
index 86d2d421b..60c5f4bd3 100644
--- a/sshd_config.5
+++ b/sshd_config.5
@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: sshd_config.5,v 1.277 2018/06/19 05:36:57 jmc Exp $
-.Dd $Mdocdate: June 19 2018 $
+.\" $OpenBSD: sshd_config.5,v 1.278 2018/07/03 10:59:35 djm Exp $
+.Dd $Mdocdate: July 3 2018 $
 .Dt SSHD_CONFIG 5
 .Os
 .Sh NAME
@@ -1332,6 +1332,12 @@ options in
 .Pa ~/.ssh/authorized_keys
 are processed by
 .Xr sshd 8 .
+Valid options are
+.Cm yes ,
+.Cm no
+or a pattern-list specifying which environment variable names to accept
+(for example
+.Qq LANG,LC_* ) .
 The default is
 .Cm no .
 Enabling environment processing may enable users to bypass access