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authorAllison Karlitskaya <allison.karlitskaya@redhat.com>2018-05-16 14:44:41 +0200
committerTomáš Mráz <t8m@users.noreply.github.com>2018-05-16 14:44:41 +0200
commit9532d85871990d41ccd3d851fff10386a4925270 (patch)
treee91d7a8b1e8ab371393bb19fb308521030ff83de /modules
parent042a387924acb3f7dd36ec48f123127500ceca8f (diff)
pam_motd: add support for a motd.d directory (#48)
Add a new feature to pam_motd to allow packages to install their own message files in a "motd.d" directory, to be displayed after the primary motd. Add an option motd_d= to specify the location of this directory. Modify the defaults, in the case where no options are given, to display both /etc/motd and /etc/motd.d. Fixes #47 * modules/pam_motd/pam_motd.c: add support for motd.d * modules/pam_motd/pam_motd.8.xml: update the manpage
Diffstat (limited to 'modules')
-rw-r--r--modules/pam_motd/pam_motd.8.xml36
-rw-r--r--modules/pam_motd/pam_motd.c100
2 files changed, 108 insertions, 28 deletions
diff --git a/modules/pam_motd/pam_motd.8.xml b/modules/pam_motd/pam_motd.8.xml
index ff92154e..906c4ed0 100644
--- a/modules/pam_motd/pam_motd.8.xml
+++ b/modules/pam_motd/pam_motd.8.xml
@@ -52,7 +52,24 @@
</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term>
+ <option>motd_dir=<replaceable>/path/dirname.d</replaceable></option>
+ </term>
+ <listitem>
+ <para>
+ The <filename>/path/dirname.d</filename> directory is scanned
+ and each file contained inside of it is displayed.
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
+ <para>
+ When no options are given, the default is to display both
+ <filename>/etc/motd</filename> and the contents of
+ <filename>/etc/motd.d</filename>. Specifying either option (or both)
+ will disable this default behavior.
+ </para>
</refsect1>
<refsect1 id="pam_motd-types">
@@ -81,7 +98,20 @@
<para>
The suggested usage for <filename>/etc/pam.d/login</filename> is:
<programlisting>
-session optional pam_motd.so motd=/etc/motd
+session optional pam_motd.so
+ </programlisting>
+ </para>
+ <para>
+ To use a <filename>motd</filename> file from a different location:
+ <programlisting>
+session optional pam_motd.so motd=/elsewhere/motd
+ </programlisting>
+ </para>
+ <para>
+ To use a <filename>motd</filename> file from elsewhere, along with a
+ corresponding <filename>.d</filename> directory:
+ <programlisting>
+session optional pam_motd.so motd=/elsewhere/motd motd_dir=/elsewhere/motd.d
</programlisting>
</para>
</refsect1>
@@ -109,6 +139,10 @@ session optional pam_motd.so motd=/etc/motd
<para>
pam_motd was written by Ben Collins &lt;bcollins@debian.org&gt;.
</para>
+ <para>
+ The <option>motd_dir=</option> option was added by
+ Allison Karlitskaya &lt;allison.karlitskaya@redhat.com&gt;.
+ </para>
</refsect1>
</refentry>
diff --git a/modules/pam_motd/pam_motd.c b/modules/pam_motd/pam_motd.c
index 11c7b565..cc828d7e 100644
--- a/modules/pam_motd/pam_motd.c
+++ b/modules/pam_motd/pam_motd.c
@@ -17,6 +17,7 @@
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
+#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <pwd.h>
@@ -33,6 +34,7 @@
#define PAM_SM_SESSION
#define DEFAULT_MOTD "/etc/motd"
+#define DEFAULT_MOTD_D "/etc/motd.d"
#include <security/pam_modules.h>
#include <security/pam_modutil.h>
@@ -47,14 +49,60 @@ pam_sm_close_session (pam_handle_t *pamh UNUSED, int flags UNUSED,
}
static char default_motd[] = DEFAULT_MOTD;
+static char default_motd_dir[] = DEFAULT_MOTD_D;
+
+static void try_to_display_fd(pam_handle_t *pamh, int fd)
+{
+ struct stat st;
+ char *mtmp = NULL;
+
+ /* fill in message buffer with contents of motd */
+ if ((fstat(fd, &st) < 0) || !st.st_size || st.st_size > 0x10000)
+ return;
+
+ if (!(mtmp = malloc(st.st_size+1)))
+ return;
+
+ if (pam_modutil_read(fd, mtmp, st.st_size) == st.st_size) {
+ if (mtmp[st.st_size-1] == '\n')
+ mtmp[st.st_size-1] = '\0';
+ else
+ mtmp[st.st_size] = '\0';
+
+ pam_info (pamh, "%s", mtmp);
+ }
+
+ _pam_drop(mtmp);
+}
+
+static void try_to_display_directory(pam_handle_t *pamh, const char *dirname)
+{
+ DIR *dirp;
+
+ dirp = opendir(dirname);
+
+ if (dirp != NULL) {
+ struct dirent *entry;
+
+ while ((entry = readdir(dirp))) {
+ int fd = openat(dirfd(dirp), entry->d_name, O_RDONLY);
+
+ if (fd >= 0) {
+ try_to_display_fd(pamh, fd);
+ close(fd);
+ }
+ }
+
+ closedir(dirp);
+ }
+}
int pam_sm_open_session(pam_handle_t *pamh, int flags,
int argc, const char **argv)
{
int retval = PAM_IGNORE;
- int fd;
const char *motd_path = NULL;
- char *mtmp = NULL;
+ const char *motd_dir_path = NULL;
if (flags & PAM_SILENT) {
return retval;
@@ -72,41 +120,39 @@ int pam_sm_open_session(pam_handle_t *pamh, int flags,
"motd= specification missing argument - ignored");
}
}
+ else if (!strncmp(*argv,"motd_dir=",9)) {
+
+ motd_dir_path = 9 + *argv;
+ if (*motd_dir_path != '\0') {
+ D(("set motd.d path: %s", motd_dir_path));
+ } else {
+ motd_dir_path = NULL;
+ pam_syslog(pamh, LOG_ERR,
+ "motd_dir= specification missing argument - ignored");
+ }
+ }
else
pam_syslog(pamh, LOG_ERR, "unknown option: %s", *argv);
}
- if (motd_path == NULL)
+ if (motd_path == NULL && motd_dir_path == NULL) {
motd_path = default_motd;
+ motd_dir_path = default_motd_dir;
+ }
- while ((fd = open(motd_path, O_RDONLY, 0)) >= 0) {
- struct stat st;
-
- /* fill in message buffer with contents of motd */
- if ((fstat(fd, &st) < 0) || !st.st_size || st.st_size > 0x10000)
- break;
-
- if (!(mtmp = malloc(st.st_size+1)))
- break;
-
- if (pam_modutil_read(fd, mtmp, st.st_size) != st.st_size)
- break;
+ if (motd_path != NULL) {
+ int fd = open(motd_path, O_RDONLY, 0);
- if (mtmp[st.st_size-1] == '\n')
- mtmp[st.st_size-1] = '\0';
- else
- mtmp[st.st_size] = '\0';
-
- pam_info (pamh, "%s", mtmp);
- break;
+ if (fd >= 0) {
+ try_to_display_fd(pamh, fd);
+ close(fd);
+ }
}
- _pam_drop (mtmp);
-
- if (fd >= 0)
- close(fd);
+ if (motd_dir_path != NULL)
+ try_to_display_directory(pamh, motd_dir_path);
- return retval;
+ return retval;
}
/* end of module definition */