1 files changed, 41 insertions, 25 deletions

diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index cfa19ca125e3..ac0a2707f6d4 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -16,48 +16,42 @@
 #include "smack.h"
 
 struct smack_known smack_known_huh = {
-        .smk_next       = NULL,
         .smk_known      = "?",
         .smk_secid      = 2,
         .smk_cipso      = NULL,
 };
 
 struct smack_known smack_known_hat = {
-        .smk_next       = &smack_known_huh,
         .smk_known      = "^",
         .smk_secid      = 3,
         .smk_cipso      = NULL,
 };
 
 struct smack_known smack_known_star = {
-        .smk_next       = &smack_known_hat,
         .smk_known      = "*",
         .smk_secid      = 4,
         .smk_cipso      = NULL,
 };
 
 struct smack_known smack_known_floor = {
-        .smk_next       = &smack_known_star,
         .smk_known      = "_",
         .smk_secid      = 5,
         .smk_cipso      = NULL,
 };
 
 struct smack_known smack_known_invalid = {
-        .smk_next       = &smack_known_floor,
         .smk_known      = "",
         .smk_secid      = 6,
         .smk_cipso      = NULL,
 };
 
 struct smack_known smack_known_web = {
-        .smk_next       = &smack_known_invalid,
         .smk_known      = "@",
         .smk_secid      = 7,
         .smk_cipso      = NULL,
 };
 
-struct smack_known *smack_known = &smack_known_web;
+LIST_HEAD(smack_known_list);
 
 /*
  * The initial value needs to be bigger than any of the
@@ -87,7 +81,6 @@ static u32 smack_next_secid = 10;
 int smk_access(char *subject_label, char *object_label, int request)
 {
         u32 may = MAY_NOT;
-        struct smk_list_entry *sp;
         struct smack_rule *srp;
 
         /*
@@ -139,9 +132,8 @@ int smk_access(char *subject_label, char *object_label, int request)
          * access (e.g. read is included in readwrite) it's
          * good.
          */
-        for (sp = smack_list; sp != NULL; sp = sp->smk_next) {
-                srp = &sp->smk_rule;
-
+        rcu_read_lock();
+        list_for_each_entry_rcu(srp, &smack_rule_list, list) {
                 if (srp->smk_subject == subject_label ||
                     strcmp(srp->smk_subject, subject_label) == 0) {
                         if (srp->smk_object == object_label ||
@@ -151,6 +143,7 @@ int smk_access(char *subject_label, char *object_label, int request)
                         }
                 }
         }
+        rcu_read_unlock();
         /*
          * This is a bit map operation.
          */
@@ -228,14 +221,17 @@ struct smack_known *smk_import_entry(const char *string, int len)
 
         mutex_lock(&smack_known_lock);
 
-        for (skp = smack_known; skp != NULL; skp = skp->smk_next)
-                if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0)
+        found = 0;
+        list_for_each_entry_rcu(skp, &smack_known_list, list) {
+                if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
+                        found = 1;
                         break;
+                }
+        }
 
-        if (skp == NULL) {
+        if (found == 0) {
                 skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
                 if (skp != NULL) {
-                        skp->smk_next = smack_known;
                         strncpy(skp->smk_known, smack, SMK_MAXLEN);
                         skp->smk_secid = smack_next_secid++;
                         skp->smk_cipso = NULL;
@@ -244,8 +240,7 @@ struct smack_known *smk_import_entry(const char *string, int len)
                          * Make sure that the entry is actually
                          * filled before putting it on the list.
                          */
-                        smp_mb();
-                        smack_known = skp;
+                        list_add_rcu(&skp->list, &smack_known_list);
                 }
         }
 
@@ -266,6 +261,9 @@ char *smk_import(const char *string, int len)
 {
         struct smack_known *skp;
 
+        /* labels cannot begin with a '-' */
+        if (string[0] == '-')
+                return NULL;
         skp = smk_import_entry(string, len);
         if (skp == NULL)
                 return NULL;
@@ -283,14 +281,19 @@ char *smack_from_secid(const u32 secid)
 {
         struct smack_known *skp;
 
-        for (skp = smack_known; skp != NULL; skp = skp->smk_next)
-                if (skp->smk_secid == secid)
+        rcu_read_lock();
+        list_for_each_entry_rcu(skp, &smack_known_list, list) {
+                if (skp->smk_secid == secid) {
+                        rcu_read_unlock();
                         return skp->smk_known;
+                }
+        }
 
         /*
          * If we got this far someone asked for the translation
          * of a secid that is not on the list.
          */
+        rcu_read_unlock();
         return smack_known_invalid.smk_known;
 }
 
@@ -305,9 +308,14 @@ u32 smack_to_secid(const char *smack)
 {
         struct smack_known *skp;
 
-        for (skp = smack_known; skp != NULL; skp = skp->smk_next)
-                if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0)
+        rcu_read_lock();
+        list_for_each_entry_rcu(skp, &smack_known_list, list) {
+                if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
+                        rcu_read_unlock();
                         return skp->smk_secid;
+                }
+        }
+        rcu_read_unlock();
         return 0;
 }
 
@@ -332,7 +340,8 @@ void smack_from_cipso(u32 level, char *cp, char *result)
         struct smack_known *kp;
         char *final = NULL;
 
-        for (kp = smack_known; final == NULL && kp != NULL; kp = kp->smk_next) {
+        rcu_read_lock();
+        list_for_each_entry(kp, &smack_known_list, list) {
                 if (kp->smk_cipso == NULL)
                         continue;
 
@@ -344,6 +353,7 @@ void smack_from_cipso(u32 level, char *cp, char *result)
 
                 spin_unlock_bh(&kp->smk_cipsolock);
         }
+        rcu_read_unlock();
         if (final == NULL)
                 final = smack_known_huh.smk_known;
         strncpy(result, final, SMK_MAXLEN);
@@ -360,13 +370,19 @@ void smack_from_cipso(u32 level, char *cp, char *result)
 int smack_to_cipso(const char *smack, struct smack_cipso *cp)
 {
         struct smack_known *kp;
+        int found = 0;
 
-        for (kp = smack_known; kp != NULL; kp = kp->smk_next)
+        rcu_read_lock();
+        list_for_each_entry_rcu(kp, &smack_known_list, list) {
                 if (kp->smk_known == smack ||
-                    strcmp(kp->smk_known, smack) == 0)
+                    strcmp(kp->smk_known, smack) == 0) {
+                        found = 1;
                         break;
+                }
+        }
+        rcu_read_unlock();
 
-        if (kp == NULL || kp->smk_cipso == NULL)
+        if (found == 0 || kp->smk_cipso == NULL)
                 return -ENOENT;
 
         memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));