X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=security%2Fdevice_cgroup.c;h=7bd296cca041aaa7e62a3f923182ff7ac2adf5ef;hb=c1159f9e8927f5732c19816a605926bc76c498b2;hp=ddd92cec78ed81c44bcfc4d9c530662a179381f2;hpb=ff877ea80efa2015b6263766f78ee42c2a1b32f9;p=linux-2.6-omap-h63xx.git diff --git a/security/device_cgroup.c b/security/device_cgroup.c index ddd92cec78e..7bd296cca04 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -41,6 +41,7 @@ struct dev_whitelist_item { short type; short access; struct list_head list; + struct rcu_head rcu; }; struct dev_cgroup { @@ -59,6 +60,11 @@ 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, @@ -128,11 +134,19 @@ static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, } if (whcopy != NULL) - list_add_tail(&whcopy->list, &dev_cgroup->whitelist); + list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist); spin_unlock(&dev_cgroup->lock); return 0; } +static void whitelist_item_free(struct rcu_head *rcu) +{ + struct dev_whitelist_item *item; + + item = container_of(rcu, struct dev_whitelist_item, rcu); + kfree(item); +} + /* * called under cgroup_lock() * since the list is visible to other tasks, we need the spinlock also @@ -156,8 +170,8 @@ static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, remove: walk->access &= ~wh->access; if (!walk->access) { - list_del(&walk->list); - kfree(walk); + list_del_rcu(&walk->list); + call_rcu(&walk->rcu, whitelist_item_free); } } spin_unlock(&dev_cgroup->lock); @@ -188,7 +202,7 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss, } wh->minor = wh->major = ~0; wh->type = DEV_ALL; - wh->access = ACC_MKNOD | ACC_READ | ACC_WRITE; + wh->access = ACC_MASK; list_add(&wh->list, &dev_cgroup->whitelist); } else { parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup); @@ -250,11 +264,10 @@ static char type_to_char(short type) static void set_majmin(char *str, unsigned m) { - memset(str, 0, MAJMINLEN); if (m == ~0) - sprintf(str, "*"); + strcpy(str, "*"); else - snprintf(str, MAJMINLEN, "%u", m); + sprintf(str, "%u", m); } static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, @@ -264,15 +277,15 @@ static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, struct dev_whitelist_item *wh; char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN]; - spin_lock(&devcgroup->lock); - list_for_each_entry(wh, &devcgroup->whitelist, list) { + rcu_read_lock(); + 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), maj, min, acc); } - spin_unlock(&devcgroup->lock); + rcu_read_unlock(); return 0; } @@ -312,10 +325,10 @@ 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 +354,19 @@ 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; + char *endp; 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; @@ -392,32 +385,23 @@ 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; b++; } else if (isdigit(*b)) { - wh.major = 0; - while (isdigit(*b)) { - wh.major = wh.major*10+(*b-'0'); - b++; - } + wh.major = simple_strtoul(b, &endp, 10); + b = endp; } else { - retval = -EINVAL; - goto out2; - } - if (*b != ':') { - retval = -EINVAL; - goto out2; + return -EINVAL; } + if (*b != ':') + return -EINVAL; b++; /* read minor */ @@ -425,19 +409,13 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft, wh.minor = ~0; b++; } else if (isdigit(*b)) { - wh.minor = 0; - while (isdigit(*b)) { - wh.minor = wh.minor*10+(*b-'0'); - b++; - } + wh.minor = simple_strtoul(b, &endp, 10); + b = endp; } 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 +432,7 @@ static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft, count = 3; break; default: - retval = -EINVAL; - goto out2; + return -EINVAL; } } @@ -463,38 +440,39 @@ 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, }, { @@ -535,8 +513,8 @@ int devcgroup_inode_permission(struct inode *inode, int mask) if (!dev_cgroup) return 0; - spin_lock(&dev_cgroup->lock); - list_for_each_entry(wh, &dev_cgroup->whitelist, list) { + rcu_read_lock(); + list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) { if (wh->type & DEV_ALL) goto acc_check; if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode)) @@ -552,10 +530,10 @@ acc_check: continue; if ((mask & MAY_READ) && !(wh->access & ACC_READ)) continue; - spin_unlock(&dev_cgroup->lock); + rcu_read_unlock(); return 0; } - spin_unlock(&dev_cgroup->lock); + rcu_read_unlock(); return -EPERM; } @@ -570,7 +548,7 @@ int devcgroup_inode_mknod(int mode, dev_t dev) if (!dev_cgroup) return 0; - spin_lock(&dev_cgroup->lock); + rcu_read_lock(); list_for_each_entry(wh, &dev_cgroup->whitelist, list) { if (wh->type & DEV_ALL) goto acc_check; @@ -585,9 +563,9 @@ int devcgroup_inode_mknod(int mode, dev_t dev) acc_check: if (!(wh->access & ACC_MKNOD)) continue; - spin_unlock(&dev_cgroup->lock); + rcu_read_unlock(); return 0; } - spin_unlock(&dev_cgroup->lock); + rcu_read_unlock(); return -EPERM; }