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authorPaul Menage <menage@google.com>2008-07-25 01:47:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:36 -0700
commitf92523e3a7861f5dbd76021e0719a35fe8771f2d (patch)
tree933c9e6e1f0683ac1c6bc019da5b91c9e567bf7c /security/device_cgroup.c
parente37123953292146445c8629b3950d0513fd10ae2 (diff)
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cgroup files: convert devcgroup_access_write() into a cgroup write_string() handler
This patch converts devcgroup_access_write() from a raw file handler into a handler for the cgroup write_string() method. This allows some boilerplate copying/locking/checking to be removed and simplifies the cleanup path, since these functions are performed by the cgroups framework before calling the handler. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/device_cgroup.c')
-rw-r--r--security/device_cgroup.c101
1 files changed, 38 insertions, 63 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index ddd92cec78e..236fffa9d05 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -59,6 +59,11 @@ static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup)
return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id));
}
+static inline struct dev_cgroup *task_devcgroup(struct task_struct *task)
+{
+ return css_to_devcgroup(task_subsys_state(task, devices_subsys_id));
+}
+
struct cgroup_subsys devices_subsys;
static int devcgroup_can_attach(struct cgroup_subsys *ss,
@@ -312,10 +317,10 @@ static int may_access_whitelist(struct dev_cgroup *c,
* when adding a new allow rule to a device whitelist, the rule
* must be allowed in the parent device
*/
-static int parent_has_perm(struct cgroup *childcg,
+static int parent_has_perm(struct dev_cgroup *childcg,
struct dev_whitelist_item *wh)
{
- struct cgroup *pcg = childcg->parent;
+ struct cgroup *pcg = childcg->css.cgroup->parent;
struct dev_cgroup *parent;
int ret;
@@ -341,39 +346,18 @@ static int parent_has_perm(struct cgroup *childcg,
* new access is only allowed if you're in the top-level cgroup, or your
* parent cgroup has the access you're asking for.
*/
-static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
- struct file *file, const char __user *userbuf,
- size_t nbytes, loff_t *ppos)
+static int devcgroup_update_access(struct dev_cgroup *devcgroup,
+ int filetype, const char *buffer)
{
- struct cgroup *cur_cgroup;
- struct dev_cgroup *devcgroup, *cur_devcgroup;
- int filetype = cft->private;
- char *buffer, *b;
+ struct dev_cgroup *cur_devcgroup;
+ const char *b;
int retval = 0, count;
struct dev_whitelist_item wh;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- devcgroup = cgroup_to_devcgroup(cgroup);
- cur_cgroup = task_cgroup(current, devices_subsys.subsys_id);
- cur_devcgroup = cgroup_to_devcgroup(cur_cgroup);
-
- buffer = kmalloc(nbytes+1, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
- if (copy_from_user(buffer, userbuf, nbytes)) {
- retval = -EFAULT;
- goto out1;
- }
- buffer[nbytes] = 0; /* nul-terminate */
-
- cgroup_lock();
- if (cgroup_is_removed(cgroup)) {
- retval = -ENODEV;
- goto out2;
- }
+ cur_devcgroup = task_devcgroup(current);
memset(&wh, 0, sizeof(wh));
b = buffer;
@@ -392,14 +376,11 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
wh.type = DEV_CHAR;
break;
default:
- retval = -EINVAL;
- goto out2;
+ return -EINVAL;
}
b++;
- if (!isspace(*b)) {
- retval = -EINVAL;
- goto out2;
- }
+ if (!isspace(*b))
+ return -EINVAL;
b++;
if (*b == '*') {
wh.major = ~0;
@@ -411,13 +392,10 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
b++;
}
} else {
- retval = -EINVAL;
- goto out2;
- }
- if (*b != ':') {
- retval = -EINVAL;
- goto out2;
+ return -EINVAL;
}
+ if (*b != ':')
+ return -EINVAL;
b++;
/* read minor */
@@ -431,13 +409,10 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
b++;
}
} else {
- retval = -EINVAL;
- goto out2;
- }
- if (!isspace(*b)) {
- retval = -EINVAL;
- goto out2;
+ return -EINVAL;
}
+ if (!isspace(*b))
+ return -EINVAL;
for (b++, count = 0; count < 3; count++, b++) {
switch (*b) {
case 'r':
@@ -454,8 +429,7 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
count = 3;
break;
default:
- retval = -EINVAL;
- goto out2;
+ return -EINVAL;
}
}
@@ -463,38 +437,39 @@ handle:
retval = 0;
switch (filetype) {
case DEVCG_ALLOW:
- if (!parent_has_perm(cgroup, &wh))
- retval = -EPERM;
- else
- retval = dev_whitelist_add(devcgroup, &wh);
- break;
+ if (!parent_has_perm(devcgroup, &wh))
+ return -EPERM;
+ return dev_whitelist_add(devcgroup, &wh);
case DEVCG_DENY:
dev_whitelist_rm(devcgroup, &wh);
break;
default:
- retval = -EINVAL;
- goto out2;
+ return -EINVAL;
}
+ return 0;
+}
- if (retval == 0)
- retval = nbytes;
-
-out2:
+static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft,
+ const char *buffer)
+{
+ int retval;
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp),
+ cft->private, buffer);
cgroup_unlock();
-out1:
- kfree(buffer);
return retval;
}
static struct cftype dev_cgroup_files[] = {
{
.name = "allow",
- .write = devcgroup_access_write,
+ .write_string = devcgroup_access_write,
.private = DEVCG_ALLOW,
},
{
.name = "deny",
- .write = devcgroup_access_write,
+ .write_string = devcgroup_access_write,
.private = DEVCG_DENY,
},
{