lkml.org 
[lkml]   [2008]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[RFC] cgroups: implement device whitelist lsm (v2)
    Implement a cgroup using the LSM interface to enforce mknod and open
    on device files.

    This implements a simple device access whitelist. A whitelist entry
    has 4 fields. 'type' is a (all), c (char), or b (block). 'all' means it
    applies to all types, all major numbers, and all minor numbers. Major and
    minor are obvious. Access is a composition of r (read), w (write), and
    m (mknod).

    The root devcgroup starts with rwm to 'all'. A child devcg gets a copy
    of the parent. Admins can then add and remove devices to the whitelist.
    Once CAP_HOST_ADMIN is introduced it will be needed to add entries as
    well or remove entries from another cgroup, though just CAP_SYS_ADMIN
    will suffice to remove entries for your own group.

    An entry is added by doing "echo <type> <maj> <min> <access>" > devcg.allow,
    for instance:

    echo b 7 0 mrw > /cgroups/1/devcg.allow

    An entry is removed by doing likewise into devcg.deny. Since this is a
    pure whitelist, not acls, you can only remove entries which exist in the
    whitelist. You must explicitly

    echo a 0 0 mrw > /cgroups/1/devcg.deny

    to remove the "allow all" entry which is automatically inherited from
    the root cgroup.

    While composing this with the ns_cgroup may seem logical, it is not
    the right thing to do, because updates to /cg/cg1/devcg.deny are
    not reflected in /cg/cg1/cg2/devcg.allow.

    A task may only be moved to another devcgroup if it is moving to
    a direct descendent of its current devcgroup.

    CAP_NS_OVERRIDE is defined as the capability needed to cross namespaces.
    A task needs both CAP_NS_OVERRIDE and CAP_SYS_ADMIN to create a new
    devcgroup, update a devcgroup's access, or move a task to a new
    devcgroup.

    CONFIG_COMMONCAP is defined whenever security/commoncap.c should
    be compiled, so that the decision of whether to show the option
    for FILE_CAPABILITIES can be a bit cleaner.

    Pavel, do you have any experience with what sorts of rules a typical
    customer would get? I wasn't sure whether it was worth having some
    sort of hash or tree for searching through a cgroup's rules since if
    most containers have say 0-2 rules then the overhead will just be
    higher.

    Changelog:
    Mar 12 2008: allow dev_cgroup lsm to be used when
    SECURITY=n, and allow stacking with SELinux
    and Smack. Don't work too hard in Kconfig
    to prevent a warning when smack+devcg are
    both compiled in, worry about that later.

    Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
    ---
    include/linux/capability.h | 11 +-
    include/linux/cgroup_subsys.h | 6 +
    include/linux/devcg.h | 55 ++++++
    include/linux/security.h | 15 ++
    init/Kconfig | 7 +
    kernel/Makefile | 1 +
    kernel/dev_cgroup.c | 411 +++++++++++++++++++++++++++++++++++++++++
    security/Kconfig | 8 +-
    security/Makefile | 12 +-
    security/dev_cgroup.c | 138 ++++++++++++++
    security/smack/smack_lsm.c | 38 ++++
    11 files changed, 692 insertions(+), 10 deletions(-)
    create mode 100644 include/linux/devcg.h
    create mode 100644 kernel/dev_cgroup.c
    create mode 100644 security/dev_cgroup.c

    diff --git a/include/linux/capability.h b/include/linux/capability.h
    index eaab759..f8ecba1 100644
    --- a/include/linux/capability.h
    +++ b/include/linux/capability.h
    @@ -333,7 +333,16 @@ typedef struct kernel_cap_struct {

    #define CAP_MAC_ADMIN 33

    -#define CAP_LAST_CAP CAP_MAC_ADMIN
    +/* Allow acting on resources in another namespace. In particular:
    + * 1. when combined with CAP_MKNOD and dev_cgroup is enabled,
    + * allow creation of devices not in the device whitelist.
    + * 2. whencombined with CAP_SYS_ADMIN and dev_cgroup is enabled,
    + * allow editing device cgroup whitelist
    + */
    +
    +#define CAP_NS_OVERRIDE 34
    +
    +#define CAP_LAST_CAP CAP_NS_OVERRIDE

    #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)

    diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
    index 1ddebfc..01e8034 100644
    --- a/include/linux/cgroup_subsys.h
    +++ b/include/linux/cgroup_subsys.h
    @@ -42,3 +42,9 @@ SUBSYS(mem_cgroup)
    #endif

    /* */
    +
    +#ifdef CONFIG_CGROUP_DEV
    +SUBSYS(devcg)
    +#endif
    +
    +/* */
    diff --git a/include/linux/devcg.h b/include/linux/devcg.h
    new file mode 100644
    index 0000000..7d9f367
    --- /dev/null
    +++ b/include/linux/devcg.h
    @@ -0,0 +1,55 @@
    +#include <linux/module.h>
    +#include <linux/cgroup.h>
    +#include <linux/fs.h>
    +#include <linux/list.h>
    +#include <linux/security.h>
    +
    +#include <asm/uaccess.h>
    +
    +#define ACC_MKNOD 1
    +#define ACC_READ 2
    +#define ACC_WRITE 4
    +
    +#define DEV_BLOCK 1
    +#define DEV_CHAR 2
    +#define DEV_ALL 4 /* this represents all devices */
    +
    +/*
    + * whitelist locking rules:
    + * cgroup_lock() cannot be taken under cgroup->lock.
    + * cgroup->lock can be taken with or without cgroup_lock().
    + *
    + * modifications always require cgroup_lock
    + * modifications to a list which is visible require the
    + * cgroup->lock *and* cgroup_lock()
    + * walking the list requires cgroup->lock or cgroup_lock().
    + *
    + * reasoning: dev_whitelist_copy() needs to kmalloc, so needs
    + * a mutex, which the cgroup_lock() is. Since modifying
    + * a visible list requires both locks, either lock can be
    + * taken for walking the list. Since the wh->spinlock is taken
    + * for modifying a public-accessible list, the spinlock is
    + * sufficient for just walking the list.
    + */
    +
    +struct dev_whitelist_item {
    + u32 major, minor;
    + short type;
    + short access;
    + struct list_head list;
    +};
    +
    +struct dev_cgroup {
    + struct cgroup_subsys_state css;
    + struct list_head whitelist;
    + spinlock_t lock;
    +};
    +
    +static inline struct dev_cgroup *cgroup_to_devcg(
    + struct cgroup *cgroup)
    +{
    + return container_of(cgroup_subsys_state(cgroup, devcg_subsys_id),
    + struct dev_cgroup, css);
    +}
    +
    +extern struct cgroup_subsys devcg_subsys;
    diff --git a/include/linux/security.h b/include/linux/security.h
    index 2231526..a818d3f 100644
    --- a/include/linux/security.h
    +++ b/include/linux/security.h
    @@ -1735,6 +1735,13 @@ int security_secctx_to_secid(char *secdata, u32 seclen, u32 *secid);
    void security_release_secctx(char *secdata, u32 seclen);

    #else /* CONFIG_SECURITY */
    +#ifdef CONFIG_CGROUP_DEV
    +extern int devcgroup_inode_mknod(struct inode *dir, struct dentry *dentry,
    + int mode, dev_t dev);
    +extern int devcgroup_inode_permission(struct inode *inode, int mask,
    + struct nameidata *nd);
    +#endif
    +
    struct security_mnt_opts {
    };

    @@ -2011,7 +2018,11 @@ static inline int security_inode_mknod (struct inode *dir,
    struct dentry *dentry,
    int mode, dev_t dev)
    {
    +#ifdef CONFIG_CGROUP_DEV
    + return devcgroup_inode_mknod(dir, dentry, mode, dev);
    +#else
    return 0;
    +#endif
    }

    static inline int security_inode_rename (struct inode *old_dir,
    @@ -2036,7 +2047,11 @@ static inline int security_inode_follow_link (struct dentry *dentry,
    static inline int security_inode_permission (struct inode *inode, int mask,
    struct nameidata *nd)
    {
    +#ifdef CONFIG_CGROUP_DEV
    + return devcgroup_inode_permission(inode, mask, nd);
    +#else
    return 0;
    +#endif
    }

    static inline int security_inode_setattr (struct dentry *dentry,
    diff --git a/init/Kconfig b/init/Kconfig
    index 009f2d8..05343a2 100644
    --- a/init/Kconfig
    +++ b/init/Kconfig
    @@ -298,6 +298,13 @@ config CGROUP_NS
    for instance virtual servers and checkpoint/restart
    jobs.

    +config CGROUP_DEV
    + bool "Device controller for cgroups"
    + depends on CGROUPS && EXPERIMENTAL
    + help
    + Provides a cgroup implementing whitelists for devices which
    + a process in the cgroup can mknod or open.
    +
    config CPUSETS
    bool "Cpuset support"
    depends on SMP && CGROUPS
    diff --git a/kernel/Makefile b/kernel/Makefile
    index 9cc073e..74cd321 100644
    --- a/kernel/Makefile
    +++ b/kernel/Makefile
    @@ -42,6 +42,7 @@ obj-$(CONFIG_CGROUPS) += cgroup.o
    obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o
    obj-$(CONFIG_CPUSETS) += cpuset.o
    obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o
    +obj-$(CONFIG_CGROUP_DEV) += dev_cgroup.o
    obj-$(CONFIG_UTS_NS) += utsname.o
    obj-$(CONFIG_USER_NS) += user_namespace.o
    obj-$(CONFIG_PID_NS) += pid_namespace.o
    diff --git a/kernel/dev_cgroup.c b/kernel/dev_cgroup.c
    new file mode 100644
    index 0000000..f088824
    --- /dev/null
    +++ b/kernel/dev_cgroup.c
    @@ -0,0 +1,411 @@
    +/*
    + * dev_cgroup.c - device cgroup subsystem
    + *
    + * Copyright 2007 IBM Corp
    + */
    +
    +#include <linux/devcg.h>
    +
    +static int devcg_can_attach(struct cgroup_subsys *ss,
    + struct cgroup *new_cgroup, struct task_struct *task)
    +{
    + struct cgroup *orig;
    +
    + if (!capable(CAP_SYS_ADMIN) || !capable(CAP_NS_OVERRIDE))
    + return -EPERM;
    +
    + if (current != task) {
    + if (!cgroup_is_descendant(new_cgroup))
    + return -EPERM;
    + }
    +
    + if (atomic_read(&new_cgroup->count) != 0)
    + return -EPERM;
    +
    + orig = task_cgroup(task, devcg_subsys_id);
    + if (orig && orig != new_cgroup->parent)
    + return -EPERM;
    +
    + return 0;
    +}
    +
    +/*
    + * called under cgroup_lock()
    + */
    +int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
    +{
    + struct dev_whitelist_item *wh, *tmp, *new;
    +
    + list_for_each_entry(wh, orig, list) {
    + new = kmalloc(sizeof(*wh), GFP_KERNEL);
    + if (!new)
    + goto free_and_exit;
    + new->major = wh->major;
    + new->minor = wh->minor;
    + new->type = wh->type;
    + new->access = wh->access;
    + list_add_tail(&new->list, dest);
    + }
    +
    + return 0;
    +
    +free_and_exit:
    + list_for_each_entry_safe(wh, tmp, dest, list) {
    + list_del(&wh->list);
    + kfree(wh);
    + }
    + return -ENOMEM;
    +}
    +
    +/* Stupid prototype - don't bother combining existing entries */
    +/*
    + * called under cgroup_lock()
    + * since the list is visible to other tasks, we need the spinlock also
    + */
    +int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
    + struct dev_whitelist_item *wh)
    +{
    + struct dev_whitelist_item *whcopy;
    +
    + whcopy = kmalloc(sizeof(*whcopy), GFP_KERNEL);
    + if (!whcopy)
    + return -ENOMEM;
    +
    + memcpy(whcopy, wh, sizeof(*whcopy));
    + spin_lock(&dev_cgroup->lock);
    + list_add_tail(&whcopy->list, &dev_cgroup->whitelist);
    + spin_unlock(&dev_cgroup->lock);
    + return 0;
    +}
    +
    +/*
    + * called under cgroup_lock()
    + * since the list is visible to other tasks, we need the spinlock also
    + */
    +void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
    + struct dev_whitelist_item *wh)
    +{
    + struct dev_whitelist_item *walk, *tmp;
    +
    + spin_lock(&dev_cgroup->lock);
    + list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) {
    + if (walk->type == DEV_ALL)
    + goto remove;
    + if (walk->type != wh->type)
    + continue;
    + if (walk->major != ~0 && walk->major != wh->major)
    + continue;
    + if (walk->minor != ~0 && walk->minor != wh->minor)
    + continue;
    +
    +remove:
    + walk->access &= ~wh->access;
    + if (!walk->access) {
    + list_del(&walk->list);
    + kfree(walk);
    + }
    + }
    + spin_unlock(&dev_cgroup->lock);
    +}
    +
    +/*
    + * Rules: you can only create a cgroup if
    + * 1. you are capable(CAP_SYS_ADMIN|CAP_NS_OVERRIDE)
    + * 2. the target cgroup is a descendant of your own cgroup
    + *
    + * Note: called from kernel/cgroup.c with cgroup_lock() held.
    + */
    +static struct cgroup_subsys_state *devcg_create(struct cgroup_subsys *ss,
    + struct cgroup *cgroup)
    +{
    + struct dev_cgroup *dev_cgroup, *parent_dev_cgroup;
    + struct cgroup *parent_cgroup;
    + int ret;
    +
    + if (!capable(CAP_SYS_ADMIN) || !capable(CAP_NS_OVERRIDE))
    + return ERR_PTR(-EPERM);
    + if (!cgroup_is_descendant(cgroup))
    + return ERR_PTR(-EPERM);
    +
    + dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
    + if (!dev_cgroup)
    + return ERR_PTR(-ENOMEM);
    + INIT_LIST_HEAD(&dev_cgroup->whitelist);
    + parent_cgroup = cgroup->parent;
    +
    + if (parent_cgroup == NULL) {
    + struct dev_whitelist_item *wh;
    + wh = kmalloc(sizeof(*wh), GFP_KERNEL);
    + wh->minor = wh->major = ~0;
    + wh->type = DEV_ALL;
    + wh->access = ACC_MKNOD | ACC_READ | ACC_WRITE;
    + list_add(&wh->list, &dev_cgroup->whitelist);
    + } else {
    + parent_dev_cgroup = cgroup_to_devcg(parent_cgroup);
    + ret = dev_whitelist_copy(&dev_cgroup->whitelist,
    + &parent_dev_cgroup->whitelist);
    + if (ret) {
    + kfree(dev_cgroup);
    + return ERR_PTR(ret);
    + }
    + }
    +
    + spin_lock_init(&dev_cgroup->lock);
    + return &dev_cgroup->css;
    +}
    +
    +static void devcg_destroy(struct cgroup_subsys *ss,
    + struct cgroup *cgroup)
    +{
    + struct dev_cgroup *dev_cgroup;
    + struct dev_whitelist_item *wh, *tmp;
    +
    + dev_cgroup = cgroup_to_devcg(cgroup);
    + list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) {
    + list_del(&wh->list);
    + kfree(wh);
    + }
    + kfree(dev_cgroup);
    +}
    +
    +#define DEVCG_ALLOW 1
    +#define DEVCG_DENY 2
    +
    +void set_access(char *acc, short access)
    +{
    + int idx = 0;
    + memset(acc, 0, 4);
    + if (access & ACC_READ)
    + acc[idx++] = 'r';
    + if (access & ACC_WRITE)
    + acc[idx++] = 'w';
    + if (access & ACC_MKNOD)
    + acc[idx++] = 'm';
    +}
    +
    +char type_to_char(short type)
    +{
    + if (type == DEV_ALL)
    + return 'a';
    + if (type == DEV_CHAR)
    + return 'c';
    + if (type == DEV_BLOCK)
    + return 'b';
    + return 'X';
    +}
    +
    +static void set_majmin(char *str, int len, unsigned m)
    +{
    + memset(str, 0, len);
    + if (m == ~0)
    + sprintf(str, "*");
    + else
    + snprintf(str, len, "%d", m);
    +}
    +
    +char *print_whitelist(struct dev_cgroup *devcgroup, int *len)
    +{
    + char *buf, *s, acc[4];
    + struct dev_whitelist_item *wh;
    + int ret;
    + int count = 0;
    + char maj[10], min[10];
    +
    + buf = kmalloc(4096, GFP_KERNEL);
    + if (!buf)
    + return ERR_PTR(-ENOMEM);
    + s = buf;
    + *s = '\0';
    + *len = 0;
    +
    + spin_lock(&devcgroup->lock);
    + list_for_each_entry(wh, &devcgroup->whitelist, list) {
    + set_access(acc, wh->access);
    + set_majmin(maj, 10, wh->major);
    + set_majmin(min, 10, wh->minor);
    + ret = snprintf(s, 4095-(s-buf), "%c %s %s %s\n",
    + type_to_char(wh->type), maj, min, acc);
    + if (s+ret >= buf+4095) {
    + kfree(buf);
    + buf = ERR_PTR(-ENOMEM);
    + break;
    + }
    + s += ret;
    + *len += ret;
    + count++;
    + }
    + spin_unlock(&devcgroup->lock);
    +
    + return buf;
    +}
    +
    +static ssize_t devcg_access_read(struct cgroup *cgroup,
    + struct cftype *cft, struct file *file,
    + char __user *userbuf, size_t nbytes, loff_t *ppos)
    +{
    + struct dev_cgroup *devcgrp = cgroup_to_devcg(cgroup);
    + int filetype = cft->private;
    + char *buffer;
    + int len, retval;
    +
    + if (filetype != DEVCG_ALLOW)
    + return -EINVAL;
    + buffer = print_whitelist(devcgrp, &len);
    + if (IS_ERR(buffer))
    + return PTR_ERR(buffer);
    +
    + retval = simple_read_from_buffer(userbuf, nbytes, ppos, buffer, len);
    + kfree(buffer);
    + return retval;
    +}
    +
    +static inline short convert_access(char *acc)
    +{
    + short access = 0;
    +
    + while (*acc) {
    + switch (*acc) {
    + case 'r':
    + case 'R': access |= ACC_READ; break;
    + case 'w':
    + case 'W': access |= ACC_WRITE; break;
    + case 'm':
    + case 'M': access |= ACC_MKNOD; break;
    + case '\n': break;
    + default:
    + return -EINVAL;
    + }
    + acc++;
    + }
    +
    + return access;
    +}
    +
    +static inline short convert_type(char intype)
    +{
    + short type = 0;
    + switch (intype) {
    + case 'a': type = DEV_ALL; break;
    + case 'c': type = DEV_CHAR; break;
    + case 'b': type = DEV_BLOCK; break;
    + default: type = -EACCES; break;
    + }
    + return type;
    +}
    +
    +static int convert_majmin(char *m, unsigned *u)
    +{
    + if (m[0] == '*') {
    + *u = ~0;
    + return 0;
    + }
    + if (sscanf(m, "%u", u) != 1)
    + return -EINVAL;
    + return 0;
    +}
    +
    +static ssize_t devcg_access_write(struct cgroup *cgroup, struct cftype *cft,
    + struct file *file, const char __user *userbuf,
    + size_t nbytes, loff_t *ppos)
    +{
    + struct cgroup *cur_cgroup;
    + struct dev_cgroup *devcgrp, *cur_devcgroup;
    + int filetype = cft->private;
    + char *buffer, acc[4], maj[10], min[10];
    + int retval = 0;
    + int nitems;
    + char type;
    + struct dev_whitelist_item wh;
    +
    + if (!capable(CAP_SYS_ADMIN) || !capable(CAP_NS_OVERRIDE))
    + return -EPERM;
    +
    + devcgrp = cgroup_to_devcg(cgroup);
    + cur_cgroup = task_cgroup(current, devcg_subsys.subsys_id);
    + cur_devcgroup = cgroup_to_devcg(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;
    + }
    +
    + memset(&wh, 0, sizeof(wh));
    + memset(acc, 0, 4);
    + nitems = sscanf(buffer, "%c %9s %9s %3s", &type, maj, min,
    + acc);
    + retval = -EINVAL;
    + if (nitems != 4)
    + goto out2;
    + wh.type = convert_type(type);
    + if (wh.type < 0)
    + goto out2;
    + wh.access = convert_access(acc);
    + if (convert_majmin(maj, &wh.major))
    + goto out2;
    + if (convert_majmin(min, &wh.minor))
    + goto out2;
    + if (wh.access < 0)
    + goto out2;
    + retval = 0;
    + switch (filetype) {
    + case DEVCG_ALLOW:
    + retval = dev_whitelist_add(devcgrp, &wh);
    + break;
    + case DEVCG_DENY:
    + dev_whitelist_rm(devcgrp, &wh);
    + break;
    + default:
    + retval = -EINVAL;
    + goto out2;
    + }
    +
    + if (retval == 0)
    + retval = nbytes;
    +
    +out2:
    + cgroup_unlock();
    +out1:
    + kfree(buffer);
    + return retval;
    +}
    +
    +static struct cftype dev_cgroup_files[] = {
    + {
    + .name = "allow",
    + .read = devcg_access_read,
    + .write = devcg_access_write,
    + .private = DEVCG_ALLOW,
    + },
    + {
    + .name = "deny",
    + .write = devcg_access_write,
    + .private = DEVCG_DENY,
    + },
    +};
    +
    +static int devcg_populate(struct cgroup_subsys *ss,
    + struct cgroup *cont)
    +{
    + return cgroup_add_files(cont, ss, dev_cgroup_files,
    + ARRAY_SIZE(dev_cgroup_files));
    +}
    +
    +struct cgroup_subsys devcg_subsys = {
    + .name = "devcg",
    + .can_attach = devcg_can_attach,
    + .create = devcg_create,
    + .destroy = devcg_destroy,
    + .populate = devcg_populate,
    + .subsys_id = devcg_subsys_id,
    +};
    diff --git a/security/Kconfig b/security/Kconfig
    index 5dfc206..8082edc 100644
    --- a/security/Kconfig
    +++ b/security/Kconfig
    @@ -75,15 +75,19 @@ config SECURITY_NETWORK_XFRM

    config SECURITY_CAPABILITIES
    bool "Default Linux Capabilities"
    - depends on SECURITY
    + depends on SECURITY && !CGROUP_DEV
    default y
    help
    This enables the "default" Linux capabilities functionality.
    If you are unsure how to answer this question, answer Y.

    +config COMMONCAP
    + bool
    + default !SECURITY || SECURITY_CAPABILITIES || SECURITY_ROOTPLUG || SECURITY_SMACK || CGROUP_DEV
    +
    config SECURITY_FILE_CAPABILITIES
    bool "File POSIX Capabilities (EXPERIMENTAL)"
    - depends on (SECURITY=n || SECURITY_CAPABILITIES!=n) && EXPERIMENTAL
    + depends on COMMONCAP && EXPERIMENTAL
    default n
    help
    This enables filesystem capabilities, allowing you to give
    diff --git a/security/Makefile b/security/Makefile
    index 9e8b025..6093003 100644
    --- a/security/Makefile
    +++ b/security/Makefile
    @@ -6,15 +6,13 @@ obj-$(CONFIG_KEYS) += keys/
    subdir-$(CONFIG_SECURITY_SELINUX) += selinux
    subdir-$(CONFIG_SECURITY_SMACK) += smack

    -# if we don't select a security model, use the default capabilities
    -ifneq ($(CONFIG_SECURITY),y)
    -obj-y += commoncap.o
    -endif
    +obj-$(CONFIG_COMMONCAP) += commoncap.o

    # Object file lists
    obj-$(CONFIG_SECURITY) += security.o dummy.o inode.o
    # Must precede capability.o in order to stack properly.
    obj-$(CONFIG_SECURITY_SELINUX) += selinux/built-in.o
    -obj-$(CONFIG_SECURITY_SMACK) += commoncap.o smack/built-in.o
    -obj-$(CONFIG_SECURITY_CAPABILITIES) += commoncap.o capability.o
    -obj-$(CONFIG_SECURITY_ROOTPLUG) += commoncap.o root_plug.o
    +obj-$(CONFIG_SECURITY_SMACK) += smack/built-in.o
    +obj-$(CONFIG_SECURITY_CAPABILITIES) += capability.o
    +obj-$(CONFIG_SECURITY_ROOTPLUG) += root_plug.o
    +obj-$(CONFIG_CGROUP_DEV) += dev_cgroup.o
    diff --git a/security/dev_cgroup.c b/security/dev_cgroup.c
    new file mode 100644
    index 0000000..cef1527
    --- /dev/null
    +++ b/security/dev_cgroup.c
    @@ -0,0 +1,138 @@
    +/*
    + * LSM portion of the device cgroup subsystem.
    + *
    + * Copyright 2007 IBM Corp
    + */
    +
    +#include <linux/devcg.h>
    +
    +int devcgroup_inode_permission(struct inode *inode, int mask,
    + struct nameidata *nd)
    +{
    + struct cgroup *cgroup;
    + struct dev_cgroup *dev_cgroup;
    + struct dev_whitelist_item *wh;
    +
    + dev_t device = inode->i_rdev;
    + if (!device)
    + return 0;
    + if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
    + return 0;
    + cgroup = task_cgroup(current, devcg_subsys.subsys_id);
    + dev_cgroup = cgroup_to_devcg(cgroup);
    + if (!dev_cgroup)
    + return 0;
    +
    + spin_lock(&dev_cgroup->lock);
    + list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
    + if (wh->type & DEV_ALL)
    + goto acc_check;
    + if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
    + continue;
    + if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
    + continue;
    + if (wh->major != ~0 && wh->major != imajor(inode))
    + continue;
    + if (wh->minor != ~0 && wh->minor != iminor(inode))
    + continue;
    +acc_check:
    + if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
    + continue;
    + if ((mask & MAY_READ) && !(wh->access & ACC_READ))
    + continue;
    + spin_unlock(&dev_cgroup->lock);
    + return 0;
    + }
    + spin_unlock(&dev_cgroup->lock);
    +
    + return -EPERM;
    +}
    +
    +int devcgroup_inode_mknod(struct inode *dir, struct dentry *dentry,
    + int mode, dev_t dev)
    +{
    + struct cgroup *cgroup;
    + struct dev_cgroup *dev_cgroup;
    + struct dev_whitelist_item *wh;
    +
    + cgroup = task_cgroup(current, devcg_subsys.subsys_id);
    + dev_cgroup = cgroup_to_devcg(cgroup);
    + if (!dev_cgroup)
    + return 0;
    +
    + spin_lock(&dev_cgroup->lock);
    + list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
    + if (wh->type & DEV_ALL)
    + goto acc_check;
    + if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
    + continue;
    + if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
    + continue;
    + if (wh->major != ~0 && wh->major != MAJOR(dev))
    + continue;
    + if (wh->minor != ~0 && wh->minor != MINOR(dev))
    + continue;
    +acc_check:
    + if (!(wh->access & ACC_MKNOD))
    + continue;
    + spin_unlock(&dev_cgroup->lock);
    + return 0;
    + }
    + spin_unlock(&dev_cgroup->lock);
    + return -EPERM;
    +}
    +
    +#ifdef CONFIG_SECURITY
    +static struct security_operations devcgroup_security_ops = {
    + .inode_mknod = devcgroup_inode_mknod,
    + .inode_permission = devcgroup_inode_permission,
    +
    + .ptrace = cap_ptrace,
    + .capget = cap_capget,
    + .capset_check = cap_capset_check,
    + .capset_set = cap_capset_set,
    + .capable = cap_capable,
    + .settime = cap_settime,
    + .netlink_send = cap_netlink_send,
    + .netlink_recv = cap_netlink_recv,
    +
    + .bprm_apply_creds = cap_bprm_apply_creds,
    + .bprm_set_security = cap_bprm_set_security,
    + .bprm_secureexec = cap_bprm_secureexec,
    +
    + .inode_setxattr = cap_inode_setxattr,
    + .inode_removexattr = cap_inode_removexattr,
    + .inode_need_killpriv = cap_inode_need_killpriv,
    + .inode_killpriv = cap_inode_killpriv,
    +
    + .task_kill = cap_task_kill,
    + .task_setscheduler = cap_task_setscheduler,
    + .task_setioprio = cap_task_setioprio,
    + .task_setnice = cap_task_setnice,
    + .task_post_setuid = cap_task_post_setuid,
    + .task_prctl = cap_task_prctl,
    + .task_reparent_to_init = cap_task_reparent_to_init,
    +
    + .syslog = cap_syslog,
    +
    + .vm_enough_memory = cap_vm_enough_memory,
    +};
    +
    +#define MY_NAME "dev_cgroup"
    +static int __init dev_cgroup_security_init(void)
    +{
    + /* register ourselves with the security framework */
    + if (register_security(&devcgroup_security_ops)) {
    + if (mod_reg_security(MY_NAME, &devcgroup_security_ops)) {
    + printk(KERN_ERR "Failure registering dev_cgroup LSM\n");
    + return -EINVAL;
    + }
    + printk(KERN_INFO "dev_cgroup LSM initialized as secondary\n");
    + return 0;
    + }
    + printk(KERN_INFO "Device cgroup LSM initialized\n");
    + return 0;
    +}
    +
    +security_initcall(dev_cgroup_security_init);
    +#endif
    diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
    index 20ec35c..08bf081 100644
    --- a/security/smack/smack_lsm.c
    +++ b/security/smack/smack_lsm.c
    @@ -36,6 +36,18 @@
    #define SOCKFS_MAGIC 0x534F434B
    #define TMPFS_MAGIC 0x01021994

    +#ifdef CONFIG_CGROUP_DEV
    +/*
    + * A better approach is probably to switch to full secondary->
    + * support for smack, but for now just hook the devcgroup lsm
    + * hooks explicitly when compiled in
    + */
    +int devcgroup_inode_mknod(struct inode *dir, struct dentry *dentry,
    + int mode, dev_t dev);
    +int devcgroup_inode_permission(struct inode *inode, int mask,
    + struct nameidata *nd);
    +#endif
    +
    /**
    * smk_fetch - Fetch the smack label from a file.
    * @ip: a pointer to the inode
    @@ -523,6 +535,12 @@ static int smack_inode_rename(struct inode *old_inode,
    static int smack_inode_permission(struct inode *inode, int mask,
    struct nameidata *nd)
    {
    +#ifdef CONFIG_CGROUP_DEV
    + int err;
    + err = devcgroup_inode_permission(inode, mask, nd);
    + if (err)
    + return err;
    +#endif
    /*
    * No permission to check. Existence test. Yup, it's there.
    */
    @@ -1370,6 +1388,23 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
    return 0;
    }

    +#ifdef CONFIG_CGROUP_DEV
    +/**
    + * smack_inode_mknod
    + * @dir contains the inode structure of parent of the new file.
    + * @dentry contains the dentry structure of the new file.
    + * @mode contains the mode of the new file.
    + * @dev contains the device number.
    + *
    + * Just calls the devcgroup hook to allow stacking.
    + */
    +static int smack_inode_mknod(struct inode *dir, struct dentry *dentry,
    + int mode, dev_t dev)
    +{
    + return devcgroup_inode_mknod(dir, dentry, mode, dev);
    +}
    +#endif
    +
    /**
    * smack_socket_post_create - finish socket setup
    * @sock: the socket
    @@ -2460,6 +2495,9 @@ struct security_operations smack_ops = {
    .inode_getsecurity = smack_inode_getsecurity,
    .inode_setsecurity = smack_inode_setsecurity,
    .inode_listsecurity = smack_inode_listsecurity,
    +#ifdef CONFIG_CGROUP_DEV
    + .inode_mknod = smack_inode_mknod,
    +#endif

    .file_permission = smack_file_permission,
    .file_alloc_security = smack_file_alloc_security,
    --
    1.5.1


    \
     
     \ /
      Last update: 2008-03-13 04:31    [W:0.073 / U:0.308 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site