2 files changed, 36 insertions, 5 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 473adc5f4f9a..1a9768a8b644 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -89,7 +89,7 @@
 #define XATTR_SELINUX_SUFFIX "selinux"
 #define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
 
-#define NUM_SEL_MNT_OPTS 4
+#define NUM_SEL_MNT_OPTS 5
 
 extern unsigned int policydb_loaded_version;
 extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
@@ -353,6 +353,7 @@ enum {
         Opt_fscontext = 2,
         Opt_defcontext = 3,
         Opt_rootcontext = 4,
+        Opt_labelsupport = 5,
 };
 
 static const match_table_t tokens = {
@@ -360,6 +361,7 @@ static const match_table_t tokens = {
         {Opt_fscontext, FSCONTEXT_STR "%s"},
         {Opt_defcontext, DEFCONTEXT_STR "%s"},
         {Opt_rootcontext, ROOTCONTEXT_STR "%s"},
+        {Opt_labelsupport, LABELSUPP_STR},
         {Opt_error, NULL},
 };
 
@@ -431,7 +433,7 @@ static int sb_finish_set_opts(struct super_block *sb)
                 }
         }
 
-        sbsec->flags |= SE_SBINITIALIZED;
+        sbsec->flags |= (SE_SBINITIALIZED | SE_SBLABELSUPP);
 
         if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
                 printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
@@ -441,6 +443,12 @@ static int sb_finish_set_opts(struct super_block *sb)
                        sb->s_id, sb->s_type->name,
                        labeling_behaviors[sbsec->behavior-1]);
 
+        if (sbsec->behavior == SECURITY_FS_USE_GENFS ||
+            sbsec->behavior == SECURITY_FS_USE_MNTPOINT ||
+            sbsec->behavior == SECURITY_FS_USE_NONE ||
+            sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
+                sbsec->flags &= ~SE_SBLABELSUPP;
+
         /* Initialize the root inode. */
         rc = inode_doinit_with_dentry(root_inode, root);
 
@@ -500,6 +508,9 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
                         opts->num_mnt_opts++;
                 tmp >>= 1;
         }
+        /* Check if the Label support flag is set */
+        if (sbsec->flags & SE_SBLABELSUPP)
+                opts->num_mnt_opts++;
 
         opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
         if (!opts->mnt_opts) {
@@ -545,6 +556,10 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
                 opts->mnt_opts[i] = context;
                 opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
         }
+        if (sbsec->flags & SE_SBLABELSUPP) {
+                opts->mnt_opts[i] = NULL;
+                opts->mnt_opts_flags[i++] = SE_SBLABELSUPP;
+        }
 
         BUG_ON(i != opts->num_mnt_opts);
 
@@ -635,6 +650,9 @@ static int selinux_set_mnt_opts(struct super_block *sb,
          */
         for (i = 0; i < num_opts; i++) {
                 u32 sid;
+
+                if (flags[i] == SE_SBLABELSUPP)
+                        continue;
                 rc = security_context_to_sid(mount_options[i],
                                              strlen(mount_options[i]), &sid);
                 if (rc) {
@@ -915,7 +933,8 @@ static int selinux_parse_opts_str(char *options,
                                 goto out_err;
                         }
                         break;
-
+                case Opt_labelsupport:
+                        break;
                 default:
                         rc = -EINVAL;
                         printk(KERN_WARNING "SELinux:  unknown mount option\n");
@@ -997,7 +1016,12 @@ static void selinux_write_opts(struct seq_file *m,
         char *prefix;
 
         for (i = 0; i < opts->num_mnt_opts; i++) {
-                char *has_comma = strchr(opts->mnt_opts[i], ',');
+                char *has_comma;
+
+                if (opts->mnt_opts[i])
+                        has_comma = strchr(opts->mnt_opts[i], ',');
+                else
+                        has_comma = NULL;
 
                 switch (opts->mnt_opts_flags[i]) {
                 case CONTEXT_MNT:
@@ -1012,6 +1036,10 @@ static void selinux_write_opts(struct seq_file *m,
                 case DEFCONTEXT_MNT:
                         prefix = DEFCONTEXT_STR;
                         break;
+                case SE_SBLABELSUPP:
+                        seq_putc(m, ',');
+                        seq_puts(m, LABELSUPP_STR);
+                        continue;
                 default:
                         BUG();
                 };
@@ -2398,7 +2426,8 @@ static inline int selinux_option(char *option, int len)
         return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
                 match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
                 match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
-                match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len));
+                match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
+                match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
 }
 
 static inline void take_option(char **to, char *from, int *first, int len)
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index ff4e19ccd8f8..e1d9db779983 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -47,11 +47,13 @@
 /* Non-mount related flags */
 #define SE_SBINITIALIZED        0x10
 #define SE_SBPROC               0x20
+#define SE_SBLABELSUPP  0x40
 
 #define CONTEXT_STR     "context="
 #define FSCONTEXT_STR   "fscontext="
 #define ROOTCONTEXT_STR "rootcontext="
 #define DEFCONTEXT_STR  "defcontext="
+#define LABELSUPP_STR "seclabel"
 
 struct netlbl_lsm_secattr;