[PATCH v2 5/6] device_cgroup: rename whitelist to exception list

From: Aristeu Rozanski
Date: Tue Sep 04 2012 - 10:36:10 EST

This patch replaces the "whitelist" usage in the code and comments and replace
them by exception list related information.

v2:
- fix checkpatch warnings

Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Aristeu Rozanski <aris@xxxxxxxxxx>

---
security/device_cgroup.c | 198 +++++++++++++++++++++++------------------------
1 file changed, 99 insertions(+), 99 deletions(-)

Index: github/security/device_cgroup.c
===================================================================
--- github.orig/security/device_cgroup.c 2012-08-21 10:51:15.000000000 -0400
+++ github/security/device_cgroup.c 2012-08-21 10:54:16.509079085 -0400
@@ -26,12 +26,12 @@
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_cgroup {
struct cgroup_subsys_state css;
- struct list_head whitelist;
+ struct list_head exceptions;
enum {
DEVCG_DEFAULT_ALLOW,
DEVCG_DEFAULT_DENY,
@@ -78,12 +78,12 @@
/*
* 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);
@@ -92,9 +92,9 @@
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;
}
@@ -102,50 +102,50 @@
/*
* 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);
@@ -154,18 +154,18 @@
}

/**
- * 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);
}
}

@@ -181,7 +181,7 @@
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)
@@ -189,8 +189,8 @@
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->behavior = parent_dev_cgroup->behavior;
mutex_unlock(&devcgroup_mutex);
if (ret) {
@@ -207,7 +207,7 @@
struct dev_cgroup *dev_cgroup;

dev_cgroup = cgroup_to_devcgroup(cgroup);
- dev_whitelist_clean(dev_cgroup);
+ dev_exception_clean(dev_cgroup);
kfree(dev_cgroup);
}

@@ -253,7 +253,7 @@
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();
@@ -270,11 +270,11 @@
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);
}
}
@@ -284,42 +284,42 @@
}

/**
- * 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
* (behavior != DEVCG_DEFAULT_DENY, !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
* (behavior == DEVCG_DEFAULT_DENY, match)
*/
if ((dev_cgroup->behavior == DEVCG_DEFAULT_DENY) == match)
@@ -329,11 +329,11 @@

/*
* 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;
@@ -341,17 +341,17 @@
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
@@ -363,25 +363,25 @@
const char *b;
char temp[12]; /* 11 + 1 characters needed for a u32 */
int count, rc;
- 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->behavior = DEVCG_DEFAULT_ALLOW;
break;
case DEVCG_DENY:
- dev_whitelist_clean(devcgroup);
+ dev_exception_clean(devcgroup);
devcgroup->behavior = DEVCG_DEFAULT_DENY;
break;
default:
@@ -389,10 +389,10 @@
}
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;
@@ -402,7 +402,7 @@
return -EINVAL;
b++;
if (*b == '*') {
- wh.major = ~0;
+ ex.major = ~0;
b++;
} else if (isdigit(*b)) {
memset(temp, 0, sizeof(temp));
@@ -412,7 +412,7 @@
if (!isdigit(*b))
break;
}
- rc = kstrtou32(temp, 10, &wh.major);
+ rc = kstrtou32(temp, 10, &ex.major);
if (rc)
return -EINVAL;
} else {
@@ -424,7 +424,7 @@

/* read minor */
if (*b == '*') {
- wh.minor = ~0;
+ ex.minor = ~0;
b++;
} else if (isdigit(*b)) {
memset(temp, 0, sizeof(temp));
@@ -434,7 +434,7 @@
if (!isdigit(*b))
break;
}
- rc = kstrtou32(temp, 10, &wh.minor);
+ rc = kstrtou32(temp, 10, &ex.minor);
if (rc)
return -EINVAL;
} else {
@@ -445,13 +445,13 @@
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':
@@ -464,7 +464,7 @@

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
@@ -472,10 +472,10 @@
* don't want to break compatibility
*/
if (devcgroup->behavior == DEVCG_DEFAULT_ALLOW) {
- 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
@@ -483,10 +483,10 @@
* don't want to break compatibility
*/
if (devcgroup->behavior == DEVCG_DEFAULT_DENY) {
- 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;
}
@@ -547,17 +547,17 @@
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)

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