file capabilities: allow sigcont within session
[safe/jmp/linux-2.6] / security / commoncap.c
index afca6dd..302e8d0 100644 (file)
 #include <linux/xattr.h>
 #include <linux/hugetlb.h>
 #include <linux/mount.h>
+#include <linux/sched.h>
+
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+/*
+ * Because of the reduced scope of CAP_SETPCAP when filesystem
+ * capabilities are in effect, it is safe to allow this capability to
+ * be available in the default configuration.
+ */
+# define CAP_INIT_BSET  CAP_FULL_SET
+#else /* ie. ndef CONFIG_SECURITY_FILE_CAPABILITIES */
+# define CAP_INIT_BSET  CAP_INIT_EFF_SET
+#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
+
+kernel_cap_t cap_bset = CAP_INIT_BSET;    /* systemwide capability bound */
+EXPORT_SYMBOL(cap_bset);
+
+/* Global security state */
+
+unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
+EXPORT_SYMBOL(securebits);
 
 int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
 {
@@ -30,8 +50,6 @@ int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
        return 0;
 }
 
-EXPORT_SYMBOL(cap_netlink_send);
-
 int cap_netlink_recv(struct sk_buff *skb, int cap)
 {
        if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
@@ -75,14 +93,44 @@ int cap_capget (struct task_struct *target, kernel_cap_t *effective,
        return 0;
 }
 
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+
+static inline int cap_block_setpcap(struct task_struct *target)
+{
+       /*
+        * No support for remote process capability manipulation with
+        * filesystem capability support.
+        */
+       return (target != current);
+}
+
+static inline int cap_inh_is_capped(void)
+{
+       /*
+        * return 1 if changes to the inheritable set are limited
+        * to the old permitted set.
+        */
+       return !cap_capable(current, CAP_SETPCAP);
+}
+
+#else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
+
+static inline int cap_block_setpcap(struct task_struct *t) { return 0; }
+static inline int cap_inh_is_capped(void) { return 1; }
+
+#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
+
 int cap_capset_check (struct task_struct *target, kernel_cap_t *effective,
                      kernel_cap_t *inheritable, kernel_cap_t *permitted)
 {
-       /* Derived from kernel/capability.c:sys_capset. */
-       /* verify restrictions on target's new Inheritable set */
-       if (!cap_issubset (*inheritable,
-                          cap_combine (target->cap_inheritable,
-                                       current->cap_permitted))) {
+       if (cap_block_setpcap(target)) {
+               return -EPERM;
+       }
+       if (cap_inh_is_capped()
+           && !cap_issubset(*inheritable,
+                            cap_combine(target->cap_inheritable,
+                                        current->cap_permitted))) {
+               /* incapable of using this inheritable set */
                return -EPERM;
        }
 
@@ -142,7 +190,8 @@ int cap_inode_killpriv(struct dentry *dentry)
        return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
 }
 
-static inline int cap_from_disk(__le32 *caps, struct linux_binprm *bprm,
+static inline int cap_from_disk(struct vfs_cap_data *caps,
+                               struct linux_binprm *bprm,
                                int size)
 {
        __u32 magic_etc;
@@ -150,7 +199,7 @@ static inline int cap_from_disk(__le32 *caps, struct linux_binprm *bprm,
        if (size != XATTR_CAPS_SZ)
                return -EINVAL;
 
-       magic_etc = le32_to_cpu(caps[0]);
+       magic_etc = le32_to_cpu(caps->magic_etc);
 
        switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
        case VFS_CAP_REVISION:
@@ -158,8 +207,8 @@ static inline int cap_from_disk(__le32 *caps, struct linux_binprm *bprm,
                        bprm->cap_effective = true;
                else
                        bprm->cap_effective = false;
-               bprm->cap_permitted = to_cap_t( le32_to_cpu(caps[1]) );
-               bprm->cap_inheritable = to_cap_t( le32_to_cpu(caps[2]) );
+               bprm->cap_permitted = to_cap_t(le32_to_cpu(caps->permitted));
+               bprm->cap_inheritable = to_cap_t(le32_to_cpu(caps->inheritable));
                return 0;
        default:
                return -EINVAL;
@@ -171,7 +220,7 @@ static int get_file_caps(struct linux_binprm *bprm)
 {
        struct dentry *dentry;
        int rc = 0;
-       __le32 v1caps[XATTR_CAPS_SZ];
+       struct vfs_cap_data incaps;
        struct inode *inode;
 
        if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) {
@@ -184,8 +233,14 @@ static int get_file_caps(struct linux_binprm *bprm)
        if (!inode->i_op || !inode->i_op->getxattr)
                goto out;
 
-       rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, &v1caps,
-                                                       XATTR_CAPS_SZ);
+       rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
+       if (rc > 0) {
+               if (rc == XATTR_CAPS_SZ)
+                       rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS,
+                                               &incaps, XATTR_CAPS_SZ);
+               else
+                       rc = -EINVAL;
+       }
        if (rc == -ENODATA || rc == -EOPNOTSUPP) {
                /* no data, that's ok */
                rc = 0;
@@ -194,7 +249,7 @@ static int get_file_caps(struct linux_binprm *bprm)
        if (rc < 0)
                goto out;
 
-       rc = cap_from_disk(v1caps, bprm, rc);
+       rc = cap_from_disk(&incaps, bprm, rc);
        if (rc)
                printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
                        __FUNCTION__, rc, bprm->filename);
@@ -287,7 +342,7 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
        /* For init, we want to retain the capabilities set
         * in the init_task struct. Thus we skip the usual
         * capability rules */
-       if (!is_init(current)) {
+       if (!is_global_init(current)) {
                current->cap_permitted = new_permitted;
                current->cap_effective = bprm->cap_effective ?
                                new_permitted : 0;
@@ -471,6 +526,10 @@ int cap_task_kill(struct task_struct *p, struct siginfo *info,
        if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
                return 0;
 
+       /* sigcont is permitted within same session */
+       if (sig == SIGCONT && (task_session_nr(current) == task_session_nr(p)))
+               return 0;
+
        if (secid)
                /*
                 * Signal sent as a particular user.
@@ -532,22 +591,3 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
        return __vm_enough_memory(mm, pages, cap_sys_admin);
 }
 
-EXPORT_SYMBOL(cap_capable);
-EXPORT_SYMBOL(cap_settime);
-EXPORT_SYMBOL(cap_ptrace);
-EXPORT_SYMBOL(cap_capget);
-EXPORT_SYMBOL(cap_capset_check);
-EXPORT_SYMBOL(cap_capset_set);
-EXPORT_SYMBOL(cap_bprm_set_security);
-EXPORT_SYMBOL(cap_bprm_apply_creds);
-EXPORT_SYMBOL(cap_bprm_secureexec);
-EXPORT_SYMBOL(cap_inode_setxattr);
-EXPORT_SYMBOL(cap_inode_removexattr);
-EXPORT_SYMBOL(cap_task_post_setuid);
-EXPORT_SYMBOL(cap_task_kill);
-EXPORT_SYMBOL(cap_task_setscheduler);
-EXPORT_SYMBOL(cap_task_setioprio);
-EXPORT_SYMBOL(cap_task_setnice);
-EXPORT_SYMBOL(cap_task_reparent_to_init);
-EXPORT_SYMBOL(cap_syslog);
-EXPORT_SYMBOL(cap_vm_enough_memory);