upstream: allow sshd_config PermitUserEnvironment to accept a

pattern-list of whitelisted environment variable names in addition to yes|no.

bz#1800, feedback and ok markus@

OpenBSD-Commit-ID: 77dc2b468e0bf04b53f333434ba257008a1fdf24

1 files changed, 15 insertions, 4 deletions

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