pam_namespace: add mntopts flag for tmpfs mount options

modules/pam_namespace/pam_namespace.h: Add mount_opts member to polydir
structure.
modules/pam_namespace/pam_namespace.c (del_polydir): Free the mount_opts.
(parse_method): Parse the mntopts flag.
(ns_setup): Pass the mount_opts to mount().
modules/pam_namespace/namespace.conf.5.xml: Document the mntopts flag.

3 files changed, 28 insertions, 3 deletions

diff --git a/modules/pam_namespace/namespace.conf.5.xml b/modules/pam_namespace/namespace.conf.5.xml
index 673099b0..c7698cb4 100644
--- a/modules/pam_namespace/namespace.conf.5.xml
+++ b/modules/pam_namespace/namespace.conf.5.xml
@@ -119,6 +119,14 @@
       contain the user name and will be shared among all users.
     </para>
 
+    <para><emphasis>mntopts</emphasis>=<replaceable>value</replaceable>
+      - value of this flag is passed to the mount call when the tmpfs mount is
+      done. It allows for example the specification of the maximum size of the
+      tmpfs instance that is created by the mount call. See <citerefentry>
+      <refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum>
+      </citerefentry> for details.
+    </para>
+
     <para>
       The directory where polyinstantiated instances are to be
       created, must exist and must have, by default, the mode of 0000.  The
diff --git a/modules/pam_namespace/pam_namespace.c b/modules/pam_namespace/pam_namespace.c
index a40f05e6..e0d5e30b 100644
--- a/modules/pam_namespace/pam_namespace.c
+++ b/modules/pam_namespace/pam_namespace.c
@@ -64,6 +64,7 @@ static void del_polydir(struct polydir_s *poly)
 	if (poly) {
 		free(poly->uid);
 		free(poly->init_script);
+		free(poly->mount_opts);
 		free(poly);
 	}
 }
@@ -237,9 +238,9 @@ static int parse_method(char *method, struct polydir_s *poly,
     static const char *method_names[] = { "user", "context", "level", "tmpdir",
 	"tmpfs", NULL };
     static const char *flag_names[] = { "create", "noinit", "iscript",
-	"shared", NULL };
+	"shared", "mntopts", NULL };
     static const unsigned int flag_values[] = { POLYDIR_CREATE, POLYDIR_NOINIT,
-	POLYDIR_ISCRIPT, POLYDIR_SHARED };
+	POLYDIR_ISCRIPT, POLYDIR_SHARED, POLYDIR_MNTOPTS };
     int i;
     char *flag;
 
@@ -279,6 +280,20 @@ static int parse_method(char *method, struct polydir_s *poly,
 					return -1;
 				};
 				break;
+
+			    case POLYDIR_MNTOPTS:
+				if (flag[namelen] != '=')
+					break;
+				if (poly->method != TMPFS) {
+					pam_syslog(idata->pamh, LOG_WARNING, "Mount options applicable only to tmpfs method");
+					break;
+				}
+				free(poly->mount_opts); /* if duplicate mntopts specified */
+				if ((poly->mount_opts = strdup(flag+namelen+1)) == NULL) {
+					pam_syslog(idata->pamh, LOG_CRIT, "Memory allocation error");
+					return -1;
+				}
+				break;
 			}
 		}
 	}
@@ -1464,7 +1479,7 @@ static int ns_setup(struct polydir_s *polyptr,
     }
 
     if (polyptr->method == TMPFS) {
-	if (mount("tmpfs", polyptr->dir, "tmpfs", 0, NULL) < 0) {
+	if (mount("tmpfs", polyptr->dir, "tmpfs", 0, polyptr->mount_opts) < 0) {
 	    pam_syslog(idata->pamh, LOG_ERR, "Error mounting tmpfs on %s, %m",
 		polyptr->dir);
             return PAM_SESSION_ERR;
diff --git a/modules/pam_namespace/pam_namespace.h b/modules/pam_namespace/pam_namespace.h
index 51d23886..47ebcc33 100644
--- a/modules/pam_namespace/pam_namespace.h
+++ b/modules/pam_namespace/pam_namespace.h
@@ -116,6 +116,7 @@
 #define POLYDIR_NOINIT        0x00000004 /* no init script */
 #define POLYDIR_SHARED        0x00000008 /* share context/level instances among users */
 #define POLYDIR_ISCRIPT       0x00000010 /* non default init script */
+#define POLYDIR_MNTOPTS       0x00000020 /* mount options for tmpfs mount */
 
 
 #define NAMESPACE_MAX_DIR_LEN 80
@@ -164,6 +165,7 @@ struct polydir_s {
     uid_t *uid;				/* list of override uids */
     unsigned int flags;			/* polydir flags */
     char *init_script;			/* path to init script */
+    char *mount_opts;			/* mount options for tmpfs mount */
     uid_t owner;			/* user which should own the polydir */
     gid_t group;			/* group which should own the polydir */
     mode_t mode;			/* mode of the polydir */