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authorTomas Mraz <tmraz@fedoraproject.org>2011-06-02 21:50:11 +0200
committerTomas Mraz <tmraz@fedoraproject.org>2011-06-02 21:50:11 +0200
commitbe52e613145564d55becf220111c0c81038eb7f6 (patch)
tree3868636bf0ad78c98ac55acdeec78cd2e6a8d523 /modules/pam_namespace
parenta1950248ee3fb08374b5733afc3d9f123634319b (diff)
Add support for the mount_private option to pam_namespace.
Diffstat (limited to 'modules/pam_namespace')
-rw-r--r--modules/pam_namespace/pam_namespace.8.xml18
-rw-r--r--modules/pam_namespace/pam_namespace.c29
-rw-r--r--modules/pam_namespace/pam_namespace.h1
3 files changed, 43 insertions, 5 deletions
diff --git a/modules/pam_namespace/pam_namespace.8.xml b/modules/pam_namespace/pam_namespace.8.xml
index 0433f0fd..f0ebe2c6 100644
--- a/modules/pam_namespace/pam_namespace.8.xml
+++ b/modules/pam_namespace/pam_namespace.8.xml
@@ -52,6 +52,9 @@
<arg choice="opt">
use_default_context
</arg>
+ <arg choice="opt">
+ mount_private
+ </arg>
</cmdsynopsis>
</refsynopsisdiv>
@@ -234,6 +237,21 @@
</listitem>
</varlistentry>
+ <varlistentry>
+ <term>
+ <option>mount_private</option>
+ </term>
+ <listitem>
+ <para>
+ This option should be used on systems where the / mount point and
+ its submounts are made shared (for example with a
+ <command>mount --make-rshared /</command> command).
+ The module will make the polyinstantiated directory mount points
+ private.
+ </para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</refsect1>
diff --git a/modules/pam_namespace/pam_namespace.c b/modules/pam_namespace/pam_namespace.c
index c47599e0..d5a2d781 100644
--- a/modules/pam_namespace/pam_namespace.c
+++ b/modules/pam_namespace/pam_namespace.c
@@ -1003,7 +1003,7 @@ static int protect_mount(int dfd, const char *path, struct instance_data *idata)
return 0;
}
-static int protect_dir(const char *path, mode_t mode, int do_mkdir,
+static int protect_dir(const char *path, mode_t mode, int do_mkdir, int always,
struct instance_data *idata)
{
char *p = strdup(path);
@@ -1082,7 +1082,7 @@ static int protect_dir(const char *path, mode_t mode, int do_mkdir,
}
}
- if (flags & O_NOFOLLOW) {
+ if ((flags & O_NOFOLLOW) || always) {
/* we are inside user-owned dir - protect */
if (protect_mount(rv, p, idata) == -1) {
save_errno = errno;
@@ -1124,7 +1124,7 @@ static int check_inst_parent(char *ipath, struct instance_data *idata)
if (trailing_slash)
*trailing_slash = '\0';
- dfd = protect_dir(inst_parent, 0, 1, idata);
+ dfd = protect_dir(inst_parent, 0, 1, 0, idata);
if (dfd == -1 || fstat(dfd, &instpbuf) < 0) {
pam_syslog(idata->pamh, LOG_ERR,
@@ -1259,7 +1259,7 @@ static int create_polydir(struct polydir_s *polyptr,
}
#endif
- rc = protect_dir(dir, mode, 1, idata);
+ rc = protect_dir(dir, mode, 1, idata->flags & PAMNS_MOUNT_PRIVATE, idata);
if (rc == -1) {
pam_syslog(idata->pamh, LOG_ERR,
"Error creating directory %s: %m", dir);
@@ -1447,7 +1447,7 @@ static int ns_setup(struct polydir_s *polyptr,
pam_syslog(idata->pamh, LOG_DEBUG,
"Set namespace for directory %s", polyptr->dir);
- retval = protect_dir(polyptr->dir, 0, 0, idata);
+ retval = protect_dir(polyptr->dir, 0, 0, idata->flags & PAMNS_MOUNT_PRIVATE, idata);
if (retval < 0 && errno != ENOENT) {
pam_syslog(idata->pamh, LOG_ERR, "Polydir %s access error: %m",
@@ -1534,6 +1534,22 @@ static int ns_setup(struct polydir_s *polyptr,
goto error_out;
}
+ if (idata->flags & PAMNS_MOUNT_PRIVATE) {
+ /*
+ * Make the polyinstantiated dir private mount. This depends
+ * on making the dir a mount point in the protect_dir call.
+ */
+ if (mount(polyptr->dir, polyptr->dir, NULL, MS_PRIVATE|MS_REC, NULL) < 0) {
+ pam_syslog(idata->pamh, LOG_ERR, "Error making %s a private mount, %m",
+ polyptr->dir);
+ goto error_out;
+ }
+ if (idata->flags & PAMNS_DEBUG)
+ pam_syslog(idata->pamh, LOG_DEBUG,
+ "Polyinstantiated directory %s made as private mount", polyptr->dir);
+
+ }
+
/*
* Bind mount instance directory on top of the polyinstantiated
* directory to provide an instance of polyinstantiated directory
@@ -1964,6 +1980,9 @@ PAM_EXTERN int pam_sm_open_session(pam_handle_t *pamh, int flags UNUSED,
idata.flags |= PAMNS_USE_DEFAULT_CONTEXT;
idata.flags |= PAMNS_CTXT_BASED_INST;
}
+ if (strcmp(argv[i], "mount_private") == 0) {
+ idata.flags |= PAMNS_MOUNT_PRIVATE;
+ }
if (strcmp(argv[i], "unmnt_remnt") == 0)
unmnt = UNMNT_REMNT;
if (strcmp(argv[i], "unmnt_only") == 0)
diff --git a/modules/pam_namespace/pam_namespace.h b/modules/pam_namespace/pam_namespace.h
index da21bd70..7b39068b 100644
--- a/modules/pam_namespace/pam_namespace.h
+++ b/modules/pam_namespace/pam_namespace.h
@@ -96,6 +96,7 @@
#define PAMNS_NO_UNMOUNT_ON_CLOSE 0x00010000 /* no unmount at session close */
#define PAMNS_USE_CURRENT_CONTEXT 0x00020000 /* use getcon instead of getexeccon */
#define PAMNS_USE_DEFAULT_CONTEXT 0x00040000 /* use get_default_context instead of getexeccon */
+#define PAMNS_MOUNT_PRIVATE 0x00080000 /* Make the polydir mounts private */
/* polydir flags */
#define POLYDIR_EXCLUSIVE 0x00000001 /* polyinstatiate exclusively for override uids */