device_cgroup: rename whitelist to exception list
Aristeu Rozanski [Fri, 5 Oct 2012 00:15:20 +0000 (17:15 -0700)]
This patch replaces the "whitelist" usage in the code and comments and replace
them by exception list related information.

Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: James Morris <jmorris@namei.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

security/device_cgroup.c

index 91cf803..44dfc41 100644 (file)
 static DEFINE_MUTEX(devcgroup_mutex);
 
 /*
- * whitelist locking rules:
+ * exception list locking rules:
  * hold devcgroup_mutex for update/read.
  * hold rcu_read_lock() for read.
  */
 
-struct dev_whitelist_item {
+struct dev_exception_item {
        u32 major, minor;
        short type;
        short access;
@@ -41,7 +41,7 @@ struct dev_whitelist_item {
 
 struct dev_cgroup {
        struct cgroup_subsys_state css;
-       struct list_head whitelist;
+       struct list_head exceptions;
        bool deny_all;
 };
 
@@ -75,12 +75,12 @@ static int devcgroup_can_attach(struct cgroup *new_cgrp,
 /*
  * called under devcgroup_mutex
  */
-static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
+static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig)
 {
-       struct dev_whitelist_item *wh, *tmp, *new;
+       struct dev_exception_item *ex, *tmp, *new;
 
-       list_for_each_entry(wh, orig, list) {
-               new = kmemdup(wh, sizeof(*wh), GFP_KERNEL);
+       list_for_each_entry(ex, orig, list) {
+               new = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
                if (!new)
                        goto free_and_exit;
                list_add_tail(&new->list, dest);
@@ -89,9 +89,9 @@ static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
        return 0;
 
 free_and_exit:
-       list_for_each_entry_safe(wh, tmp, dest, list) {
-               list_del(&wh->list);
-               kfree(wh);
+       list_for_each_entry_safe(ex, tmp, dest, list) {
+               list_del(&ex->list);
+               kfree(ex);
        }
        return -ENOMEM;
 }
@@ -99,50 +99,50 @@ free_and_exit:
 /*
  * called under devcgroup_mutex
  */
-static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
-                       struct dev_whitelist_item *wh)
+static int dev_exception_add(struct dev_cgroup *dev_cgroup,
+                            struct dev_exception_item *ex)
 {
-       struct dev_whitelist_item *whcopy, *walk;
+       struct dev_exception_item *excopy, *walk;
 
-       whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL);
-       if (!whcopy)
+       excopy = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
+       if (!excopy)
                return -ENOMEM;
 
-       list_for_each_entry(walk, &dev_cgroup->whitelist, list) {
-               if (walk->type != wh->type)
+       list_for_each_entry(walk, &dev_cgroup->exceptions, list) {
+               if (walk->type != ex->type)
                        continue;
-               if (walk->major != wh->major)
+               if (walk->major != ex->major)
                        continue;
-               if (walk->minor != wh->minor)
+               if (walk->minor != ex->minor)
                        continue;
 
-               walk->access |= wh->access;
-               kfree(whcopy);
-               whcopy = NULL;
+               walk->access |= ex->access;
+               kfree(excopy);
+               excopy = NULL;
        }
 
-       if (whcopy != NULL)
-               list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist);
+       if (excopy != NULL)
+               list_add_tail_rcu(&excopy->list, &dev_cgroup->exceptions);
        return 0;
 }
 
 /*
  * called under devcgroup_mutex
  */
-static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
-                       struct dev_whitelist_item *wh)
+static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
+                            struct dev_exception_item *ex)
 {
-       struct dev_whitelist_item *walk, *tmp;
+       struct dev_exception_item *walk, *tmp;
 
-       list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) {
-               if (walk->type != wh->type)
+       list_for_each_entry_safe(walk, tmp, &dev_cgroup->exceptions, list) {
+               if (walk->type != ex->type)
                        continue;
-               if (walk->major != wh->major)
+               if (walk->major != ex->major)
                        continue;
-               if (walk->minor != wh->minor)
+               if (walk->minor != ex->minor)
                        continue;
 
-               walk->access &= ~wh->access;
+               walk->access &= ~ex->access;
                if (!walk->access) {
                        list_del_rcu(&walk->list);
                        kfree_rcu(walk, rcu);
@@ -151,18 +151,18 @@ static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
 }
 
 /**
- * dev_whitelist_clean - frees all entries of the whitelist
- * @dev_cgroup: dev_cgroup with the whitelist to be cleaned
+ * dev_exception_clean - frees all entries of the exception list
+ * @dev_cgroup: dev_cgroup with the exception list to be cleaned
  *
  * called under devcgroup_mutex
  */
-static void dev_whitelist_clean(struct dev_cgroup *dev_cgroup)
+static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
 {
-       struct dev_whitelist_item *wh, *tmp;
+       struct dev_exception_item *ex, *tmp;
 
-       list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) {
-               list_del(&wh->list);
-               kfree(wh);
+       list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
+               list_del(&ex->list);
+               kfree(ex);
        }
 }
 
@@ -178,7 +178,7 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup)
        dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
        if (!dev_cgroup)
                return ERR_PTR(-ENOMEM);
-       INIT_LIST_HEAD(&dev_cgroup->whitelist);
+       INIT_LIST_HEAD(&dev_cgroup->exceptions);
        parent_cgroup = cgroup->parent;
 
        if (parent_cgroup == NULL)
@@ -186,8 +186,8 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup)
        else {
                parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
                mutex_lock(&devcgroup_mutex);
-               ret = dev_whitelist_copy(&dev_cgroup->whitelist,
-                               &parent_dev_cgroup->whitelist);
+               ret = dev_exceptions_copy(&dev_cgroup->exceptions,
+                                         &parent_dev_cgroup->exceptions);
                dev_cgroup->deny_all = parent_dev_cgroup->deny_all;
                mutex_unlock(&devcgroup_mutex);
                if (ret) {
@@ -204,7 +204,7 @@ static void devcgroup_destroy(struct cgroup *cgroup)
        struct dev_cgroup *dev_cgroup;
 
        dev_cgroup = cgroup_to_devcgroup(cgroup);
-       dev_whitelist_clean(dev_cgroup);
+       dev_exception_clean(dev_cgroup);
        kfree(dev_cgroup);
 }
 
@@ -250,7 +250,7 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
                                struct seq_file *m)
 {
        struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
-       struct dev_whitelist_item *wh;
+       struct dev_exception_item *ex;
        char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
 
        rcu_read_lock();
@@ -267,11 +267,11 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
                seq_printf(m, "%c %s:%s %s\n", type_to_char(DEV_ALL),
                           maj, min, acc);
        } else {
-               list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) {
-                       set_access(acc, wh->access);
-                       set_majmin(maj, wh->major);
-                       set_majmin(min, wh->minor);
-                       seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type),
+               list_for_each_entry_rcu(ex, &devcgroup->exceptions, list) {
+                       set_access(acc, ex->access);
+                       set_majmin(maj, ex->major);
+                       set_majmin(min, ex->minor);
+                       seq_printf(m, "%c %s:%s %s\n", type_to_char(ex->type),
                                   maj, min, acc);
                }
        }
@@ -281,42 +281,42 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
 }
 
 /**
- * may_access_whitelist - verifies if a new rule is part of what is allowed
- *                       by a dev cgroup based on the default policy +
- *                       exceptions. This is used to make sure a child cgroup
- *                       won't have more privileges than its parent or to
- *                       verify if a certain access is allowed.
+ * may_access - verifies if a new exception is part of what is allowed
+ *             by a dev cgroup based on the default policy +
+ *             exceptions. This is used to make sure a child cgroup
+ *             won't have more privileges than its parent or to
+ *             verify if a certain access is allowed.
  * @dev_cgroup: dev cgroup to be tested against
- * @refwh: new rule
+ * @refex: new exception
  */
-static int may_access_whitelist(struct dev_cgroup *dev_cgroup,
-                               struct dev_whitelist_item *refwh)
+static int may_access(struct dev_cgroup *dev_cgroup,
+                     struct dev_exception_item *refex)
 {
-       struct dev_whitelist_item *whitem;
+       struct dev_exception_item *ex;
        bool match = false;
 
-       list_for_each_entry(whitem, &dev_cgroup->whitelist, list) {
-               if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK))
+       list_for_each_entry(ex, &dev_cgroup->exceptions, list) {
+               if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK))
                        continue;
-               if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR))
+               if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR))
                        continue;
-               if (whitem->major != ~0 && whitem->major != refwh->major)
+               if (ex->major != ~0 && ex->major != refex->major)
                        continue;
-               if (whitem->minor != ~0 && whitem->minor != refwh->minor)
+               if (ex->minor != ~0 && ex->minor != refex->minor)
                        continue;
-               if (refwh->access & (~whitem->access))
+               if (refex->access & (~ex->access))
                        continue;
                match = true;
                break;
        }
 
        /*
-        * In two cases we'll consider this new rule valid:
+        * In two cases we'll consider this new exception valid:
         * - the dev cgroup has its default policy to allow + exception list:
-        *   the new rule should *not* match any of the exceptions
+        *   the new exception should *not* match any of the exceptions
         *   (!deny_all, !match)
         * - the dev cgroup has its default policy to deny + exception list:
-        *   the new rule *should* match the exceptions
+        *   the new exception *should* match the exceptions
         *   (deny_all, match)
         */
        if (dev_cgroup->deny_all == match)
@@ -326,11 +326,11 @@ static int may_access_whitelist(struct dev_cgroup *dev_cgroup,
 
 /*
  * parent_has_perm:
- * when adding a new allow rule to a device whitelist, the rule
+ * when adding a new allow rule to a device exception list, the rule
  * must be allowed in the parent device
  */
 static int parent_has_perm(struct dev_cgroup *childcg,
-                                 struct dev_whitelist_item *wh)
+                                 struct dev_exception_item *ex)
 {
        struct cgroup *pcg = childcg->css.cgroup->parent;
        struct dev_cgroup *parent;
@@ -338,17 +338,17 @@ static int parent_has_perm(struct dev_cgroup *childcg,
        if (!pcg)
                return 1;
        parent = cgroup_to_devcgroup(pcg);
-       return may_access_whitelist(parent, wh);
+       return may_access(parent, ex);
 }
 
 /*
- * Modify the whitelist using allow/deny rules.
+ * Modify the exception list using allow/deny rules.
  * CAP_SYS_ADMIN is needed for this.  It's at least separate from CAP_MKNOD
  * so we can give a container CAP_MKNOD to let it create devices but not
- * modify the whitelist.
+ * modify the exception list.
  * It seems likely we'll want to add a CAP_CONTAINER capability to allow
  * us to also grant CAP_SYS_ADMIN to containers without giving away the
- * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN
+ * device exception list controls, but for now we'll stick with CAP_SYS_ADMIN
  *
  * Taking rules away is always allowed (given CAP_SYS_ADMIN).  Granting
  * new access is only allowed if you're in the top-level cgroup, or your
@@ -360,25 +360,25 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
        const char *b;
        char *endp;
        int count;
-       struct dev_whitelist_item wh;
+       struct dev_exception_item ex;
 
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
 
-       memset(&wh, 0, sizeof(wh));
+       memset(&ex, 0, sizeof(ex));
        b = buffer;
 
        switch (*b) {
        case 'a':
                switch (filetype) {
                case DEVCG_ALLOW:
-                       if (!parent_has_perm(devcgroup, &wh))
+                       if (!parent_has_perm(devcgroup, &ex))
                                return -EPERM;
-                       dev_whitelist_clean(devcgroup);
+                       dev_exception_clean(devcgroup);
                        devcgroup->deny_all = false;
                        break;
                case DEVCG_DENY:
-                       dev_whitelist_clean(devcgroup);
+                       dev_exception_clean(devcgroup);
                        devcgroup->deny_all = true;
                        break;
                default:
@@ -386,10 +386,10 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
                }
                return 0;
        case 'b':
-               wh.type = DEV_BLOCK;
+               ex.type = DEV_BLOCK;
                break;
        case 'c':
-               wh.type = DEV_CHAR;
+               ex.type = DEV_CHAR;
                break;
        default:
                return -EINVAL;
@@ -399,10 +399,10 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
                return -EINVAL;
        b++;
        if (*b == '*') {
-               wh.major = ~0;
+               ex.major = ~0;
                b++;
        } else if (isdigit(*b)) {
-               wh.major = simple_strtoul(b, &endp, 10);
+               ex.major = simple_strtoul(b, &endp, 10);
                b = endp;
        } else {
                return -EINVAL;
@@ -413,10 +413,10 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
 
        /* read minor */
        if (*b == '*') {
-               wh.minor = ~0;
+               ex.minor = ~0;
                b++;
        } else if (isdigit(*b)) {
-               wh.minor = simple_strtoul(b, &endp, 10);
+               ex.minor = simple_strtoul(b, &endp, 10);
                b = endp;
        } else {
                return -EINVAL;
@@ -426,13 +426,13 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
        for (b++, count = 0; count < 3; count++, b++) {
                switch (*b) {
                case 'r':
-                       wh.access |= ACC_READ;
+                       ex.access |= ACC_READ;
                        break;
                case 'w':
-                       wh.access |= ACC_WRITE;
+                       ex.access |= ACC_WRITE;
                        break;
                case 'm':
-                       wh.access |= ACC_MKNOD;
+                       ex.access |= ACC_MKNOD;
                        break;
                case '\n':
                case '\0':
@@ -445,7 +445,7 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
 
        switch (filetype) {
        case DEVCG_ALLOW:
-               if (!parent_has_perm(devcgroup, &wh))
+               if (!parent_has_perm(devcgroup, &ex))
                        return -EPERM;
                /*
                 * If the default policy is to allow by default, try to remove
@@ -453,10 +453,10 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
                 * don't want to break compatibility
                 */
                if (devcgroup->deny_all == false) {
-                       dev_whitelist_rm(devcgroup, &wh);
+                       dev_exception_rm(devcgroup, &ex);
                        return 0;
                }
-               return dev_whitelist_add(devcgroup, &wh);
+               return dev_exception_add(devcgroup, &ex);
        case DEVCG_DENY:
                /*
                 * If the default policy is to deny by default, try to remove
@@ -464,10 +464,10 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
                 * don't want to break compatibility
                 */
                if (devcgroup->deny_all == true) {
-                       dev_whitelist_rm(devcgroup, &wh);
+                       dev_exception_rm(devcgroup, &ex);
                        return 0;
                }
-               return dev_whitelist_add(devcgroup, &wh);
+               return dev_exception_add(devcgroup, &ex);
        default:
                return -EINVAL;
        }
@@ -537,17 +537,17 @@ static int __devcgroup_check_permission(struct dev_cgroup *dev_cgroup,
                                        short type, u32 major, u32 minor,
                                        short access)
 {
-       struct dev_whitelist_item wh;
+       struct dev_exception_item ex;
        int rc;
 
-       memset(&wh, 0, sizeof(wh));
-       wh.type = type;
-       wh.major = major;
-       wh.minor = minor;
-       wh.access = access;
+       memset(&ex, 0, sizeof(ex));
+       ex.type = type;
+       ex.major = major;
+       ex.minor = minor;
+       ex.access = access;
 
        rcu_read_lock();
-       rc = may_access_whitelist(dev_cgroup, &wh);
+       rc = may_access(dev_cgroup, &ex);
        rcu_read_unlock();
 
        if (!rc)