pam_motd: Fix segmentation fault when no motd_dir specified (#76)

This fixes a regression introduced by #69, where motd_path was set
to NULL and passed into strdup() if the motd_dir argument was
not specified in the configuration file. This caused a segmentation
fault.

* modules/pam_motd/pam_motd.c: fix checks for NULL in arguments
* xtests/Makefile.am: add test scripts and config file
* xtests/tst-pam_motd.sh: add running tst-pam_motd4.sh
* xtests/tst-pam_motd4.pamd: create
* xtests/tst-pam_motd4.sh: create

diff --git a/modules/pam_motd/pam_motd.c b/modules/pam_motd/pam_motd.c
index 1c1cfcfa31ae978b8d9ca307d55c7d9c057d57ee..ec3ebd58d8adb72495e0c97127e008504fee3ffd 100644 (file)
--- a/modules/pam_motd/pam_motd.c
+++ b/modules/pam_motd/pam_motd.c
@@ -132,7 +132,6 @@ static int pam_split_string(const pam_handle_t *pamh, char *arg, char delim,
        goto out;
     }
 
-
     arg_extracted = strtok_r(arg, delim_str, &arg);
     while (arg_extracted != NULL && i < num_strs) {
        arg_split[i++] = arg_extracted;
@@ -363,15 +362,21 @@ int pam_sm_open_session(pam_handle_t *pamh, int flags,
        motd_dir_path = default_motd_dir;
     }
 
-    motd_path_copy = strdup(motd_path);
+    if (motd_path != NULL) {
+       motd_path_copy = strdup(motd_path);
+    }
+
     if (motd_path_copy != NULL) {
-       if (pam_split_string(pamh, motd_path_copy, ':', &motd_path_split,
-               &num_motd_paths) == 0) {
+       if (pam_split_string(pamh, motd_path_copy, ':',
+               &motd_path_split, &num_motd_paths) == 0) {
            goto out;
        }
     }
 
-    motd_dir_path_copy = strdup(motd_dir_path);
+    if (motd_dir_path != NULL) {
+       motd_dir_path_copy = strdup(motd_dir_path);
+    }
+
     if (motd_dir_path_copy != NULL) {
        if (pam_split_string(pamh, motd_dir_path_copy, ':',
                &motd_dir_path_split, &num_motd_dir_paths) == 0) {

diff --git a/xtests/Makefile.am b/xtests/Makefile.am
index 555d5e334d2361f1d0f6114cc88ea89801cbadba..4d5aba3db4a051e21cbe7afe0e8e9c410c987add 100644 (file)
--- a/xtests/Makefile.am
+++ b/xtests/Makefile.am
@@ -34,8 +34,8 @@ EXTRA_DIST = run-xtests.sh tst-pam_dispatch1.pamd tst-pam_dispatch2.pamd \
        tst-pam_pwhistory1.pamd tst-pam_pwhistory1.sh \
        tst-pam_time1.pamd time.conf \
        tst-pam_motd.sh tst-pam_motd1.sh tst-pam_motd2.sh \
-       tst-pam_motd3.sh tst-pam_motd1.pamd \
-       tst-pam_motd2.pamd tst-pam_motd3.pamd
+       tst-pam_motd3.sh tst-pam_motd4.sh tst-pam_motd1.pamd \
+       tst-pam_motd2.pamd tst-pam_motd3.pamd tst-pam_motd4.pamd
 
 XTESTS = tst-pam_dispatch1 tst-pam_dispatch2 tst-pam_dispatch3 \
        tst-pam_dispatch4 tst-pam_dispatch5 \

diff --git a/xtests/tst-pam_motd.sh b/xtests/tst-pam_motd.sh
index 9b0c38f6ddbc7fa47d8a0e551e3bc35c66134847..90801280361331e88155c6727327238fa6e6f5ae 100755 (executable)
--- a/xtests/tst-pam_motd.sh
+++ b/xtests/tst-pam_motd.sh
@@ -5,3 +5,4 @@ set -e
 ./tst-pam_motd1.sh
 ./tst-pam_motd2.sh
 ./tst-pam_motd3.sh
+./tst-pam_motd4.sh

diff --git a/xtests/tst-pam_motd4.pamd b/xtests/tst-pam_motd4.pamd
new file mode 100644 (file)
index 0000000..9dc311a
--- /dev/null
+++ b/xtests/tst-pam_motd4.pamd
@@ -0,0 +1,3 @@
+#%PAM-1.0
+session    required    pam_permit.so
+session    optional    pam_motd.so motd=tst-pam_motd4.d/etc/motd

diff --git a/xtests/tst-pam_motd4.sh b/xtests/tst-pam_motd4.sh
new file mode 100755 (executable)
index 0000000..6022177
--- /dev/null
+++ b/xtests/tst-pam_motd4.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+TST_DIR="tst-pam_motd4.d"
+
+function tst_cleanup() {
+    rm -rf "${TST_DIR}"
+    rm -f tst-pam_motd4.out
+}
+
+mkdir -p ${TST_DIR}/etc
+
+# Verify the case of single motd with no motd_dir given in tst-pam_motd4.pamd
+echo "motd: /etc/motd" > ${TST_DIR}/etc/motd
+
+./tst-pam_motd tst-pam_motd4 > tst-pam_motd4.out
+
+RET=$?
+
+motd_to_show_output=$(cat tst-pam_motd4.out | grep "motd: /etc/motd")
+if [ -z "${motd_to_show_output}" ];
+then
+    tst_cleanup
+    exit 1
+fi
+
+tst_cleanup
+exit $RET