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authordjm@openbsd.org <djm@openbsd.org>2018-07-03 10:59:35 +0000
committerDamien Miller <djm@mindrot.org>2018-07-03 21:01:30 +1000
commit95344c257412b51199ead18d54eaed5bafb75617 (patch)
tree320a21db8781ca4f6a363db928ca04b3b0d1dd70
parent6f56fe4b9578b0627667f8bce69d4d938a88324c (diff)
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
-rw-r--r--servconf.c40
-rw-r--r--servconf.h4
-rw-r--r--session.c19
-rw-r--r--sshd_config.510
4 files changed, 62 insertions, 11 deletions
diff --git a/servconf.c b/servconf.c
index cb578658..a41fdc26 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 db8362c6..73327135 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 85df6a27..3c4e9c44 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 86d2d421..60c5f4bd 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