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Message-ID: <20120905032402.GE13310@mail.hallyn.com>
Date: Wed, 5 Sep 2012 03:24:02 +0000
From: "Serge E. Hallyn" <serge@...lyn.com>
To: Aristeu Rozanski <aris@...hat.com>
Cc: linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
Tejun Heo <tj@...nel.org>, Li Zefan <lizefan@...wei.com>,
James Morris <jmorris@...ei.org>,
Pavel Emelyanov <xemul@...nvz.org>,
Serge Hallyn <serge.hallyn@...onical.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2 5/6] device_cgroup: rename whitelist to exception
list
Quoting Aristeu Rozanski (aris@...hat.com):
> 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@...nel.org>
> Cc: Li Zefan <lizefan@...wei.com>
> Cc: James Morris <jmorris@...ei.org>
> Cc: Pavel Emelyanov <xemul@...nvz.org>
> Cc: Serge Hallyn <serge.hallyn@...onical.com>
Acked-by: Serge Hallyn <serge.hallyn@...onical.com>
> Signed-off-by: Aristeu Rozanski <aris@...hat.com>
>
> ---
> 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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