-/* Common capabilities, needed by capability.o and root_plug.o
+/* Common capabilities, needed by capability.o and root_plug.o
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
-#include <linux/smp_lock.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/ptrace.h>
#include <linux/xattr.h>
#include <linux/hugetlb.h>
+#include <linux/mount.h>
+#include <linux/sched.h>
+#include <linux/prctl.h>
+#include <linux/securebits.h>
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))
EXPORT_SYMBOL(cap_netlink_recv);
+/*
+ * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
+ * function. That is, it has the reverse semantics: cap_capable()
+ * returns 0 when a task has a capability, but the kernel's capable()
+ * returns 1 for this case.
+ */
int cap_capable (struct task_struct *tsk, int cap)
{
/* Derived from include/linux/sched.h:capable. */
return 0;
}
-int cap_ptrace (struct task_struct *parent, struct task_struct *child)
+int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
{
/* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
- if (!cap_issubset(child->cap_permitted, parent->cap_permitted) &&
- !__capable(parent, CAP_SYS_PTRACE))
- return -EPERM;
- return 0;
+ if (cap_issubset(child->cap_permitted, current->cap_permitted))
+ return 0;
+ if (capable(CAP_SYS_PTRACE))
+ return 0;
+ return -EPERM;
+}
+
+int cap_ptrace_traceme(struct task_struct *parent)
+{
+ /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
+ if (cap_issubset(current->cap_permitted, parent->cap_permitted))
+ return 0;
+ if (has_capability(parent, CAP_SYS_PTRACE))
+ return 0;
+ return -EPERM;
}
int cap_capget (struct task_struct *target, kernel_cap_t *effective,
kernel_cap_t *inheritable, kernel_cap_t *permitted)
{
/* Derived from kernel/capability.c:sys_capget. */
- *effective = cap_t (target->cap_effective);
- *inheritable = cap_t (target->cap_inheritable);
- *permitted = cap_t (target->cap_permitted);
+ *effective = target->cap_effective;
+ *inheritable = target->cap_inheritable;
+ *permitted = target->cap_permitted;
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. That is, if the current task
+ * does *not* possess the CAP_SETPCAP capability.
+ */
+ return (cap_capable(current, CAP_SETPCAP) != 0);
+}
+
+static inline int cap_limit_ptraced_target(void) { return 1; }
+
+#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; }
+static inline int cap_limit_ptraced_target(void)
+{
+ return !capable(CAP_SETPCAP);
+}
+
+#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;
+ }
+ if (!cap_issubset(*inheritable,
+ cap_combine(target->cap_inheritable,
+ current->cap_bset))) {
+ /* no new pI capabilities outside bounding set */
return -EPERM;
}
target->cap_permitted = *permitted;
}
-int cap_bprm_set_security (struct linux_binprm *bprm)
+static inline void bprm_clear_caps(struct linux_binprm *bprm)
{
- /* Copied from fs/exec.c:prepare_binprm. */
+ cap_clear(bprm->cap_post_exec_permitted);
+ bprm->cap_effective = false;
+}
- /* We don't have VFS support for capabilities yet */
- cap_clear (bprm->cap_inheritable);
- cap_clear (bprm->cap_permitted);
- cap_clear (bprm->cap_effective);
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
- /* To support inheritance of root-permissions and suid-root
- * executables under compatibility mode, we raise all three
- * capability sets for the file.
- *
- * If only the real uid is 0, we only raise the inheritable
- * and permitted sets of the executable file.
- */
+int cap_inode_need_killpriv(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ int error;
- if (!issecure (SECURE_NOROOT)) {
- if (bprm->e_uid == 0 || current->uid == 0) {
- cap_set_full (bprm->cap_inheritable);
- cap_set_full (bprm->cap_permitted);
+ if (!inode->i_op || !inode->i_op->getxattr)
+ return 0;
+
+ error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
+ if (error <= 0)
+ return 0;
+ return 1;
+}
+
+int cap_inode_killpriv(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ if (!inode->i_op || !inode->i_op->removexattr)
+ return 0;
+
+ return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
+}
+
+static inline int cap_from_disk(struct vfs_cap_data *caps,
+ struct linux_binprm *bprm, unsigned size)
+{
+ __u32 magic_etc;
+ unsigned tocopy, i;
+ int ret;
+
+ if (size < sizeof(magic_etc))
+ return -EINVAL;
+
+ magic_etc = le32_to_cpu(caps->magic_etc);
+
+ switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
+ case VFS_CAP_REVISION_1:
+ if (size != XATTR_CAPS_SZ_1)
+ return -EINVAL;
+ tocopy = VFS_CAP_U32_1;
+ break;
+ case VFS_CAP_REVISION_2:
+ if (size != XATTR_CAPS_SZ_2)
+ return -EINVAL;
+ tocopy = VFS_CAP_U32_2;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE) {
+ bprm->cap_effective = true;
+ } else {
+ bprm->cap_effective = false;
+ }
+
+ ret = 0;
+
+ CAP_FOR_EACH_U32(i) {
+ __u32 value_cpu;
+
+ if (i >= tocopy) {
+ /*
+ * Legacy capability sets have no upper bits
+ */
+ bprm->cap_post_exec_permitted.cap[i] = 0;
+ continue;
+ }
+ /*
+ * pP' = (X & fP) | (pI & fI)
+ */
+ value_cpu = le32_to_cpu(caps->data[i].permitted);
+ bprm->cap_post_exec_permitted.cap[i] =
+ (current->cap_bset.cap[i] & value_cpu) |
+ (current->cap_inheritable.cap[i] &
+ le32_to_cpu(caps->data[i].inheritable));
+ if (value_cpu & ~bprm->cap_post_exec_permitted.cap[i]) {
+ /*
+ * insufficient to execute correctly
+ */
+ ret = -EPERM;
}
- if (bprm->e_uid == 0)
- cap_set_full (bprm->cap_effective);
}
+
+ /*
+ * For legacy apps, with no internal support for recognizing they
+ * do not have enough capabilities, we return an error if they are
+ * missing some "forced" (aka file-permitted) capabilities.
+ */
+ return bprm->cap_effective ? ret : 0;
+}
+
+/* Locate any VFS capabilities: */
+static int get_file_caps(struct linux_binprm *bprm)
+{
+ struct dentry *dentry;
+ int rc = 0;
+ struct vfs_cap_data vcaps;
+ struct inode *inode;
+
+ bprm_clear_caps(bprm);
+
+ if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
+ return 0;
+
+ dentry = dget(bprm->file->f_dentry);
+ inode = dentry->d_inode;
+ if (!inode->i_op || !inode->i_op->getxattr)
+ goto out;
+
+ rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, &vcaps,
+ XATTR_CAPS_SZ);
+ if (rc == -ENODATA || rc == -EOPNOTSUPP) {
+ /* no data, that's ok */
+ rc = 0;
+ goto out;
+ }
+ if (rc < 0)
+ goto out;
+
+ rc = cap_from_disk(&vcaps, bprm, rc);
+ if (rc == -EINVAL)
+ printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
+ __func__, rc, bprm->filename);
+
+out:
+ dput(dentry);
+ if (rc)
+ bprm_clear_caps(bprm);
+
+ return rc;
+}
+
+#else
+int cap_inode_need_killpriv(struct dentry *dentry)
+{
return 0;
}
-void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
+int cap_inode_killpriv(struct dentry *dentry)
{
- /* Derived from fs/exec.c:compute_creds. */
- kernel_cap_t new_permitted, working;
+ return 0;
+}
- new_permitted = cap_intersect (bprm->cap_permitted, cap_bset);
- working = cap_intersect (bprm->cap_inheritable,
- current->cap_inheritable);
- new_permitted = cap_combine (new_permitted, working);
+static inline int get_file_caps(struct linux_binprm *bprm)
+{
+ bprm_clear_caps(bprm);
+ return 0;
+}
+#endif
+int cap_bprm_set_security (struct linux_binprm *bprm)
+{
+ int ret;
+
+ ret = get_file_caps(bprm);
+
+ if (!issecure(SECURE_NOROOT)) {
+ /*
+ * To support inheritance of root-permissions and suid-root
+ * executables under compatibility mode, we override the
+ * capability sets for the file.
+ *
+ * If only the real uid is 0, we do not set the effective
+ * bit.
+ */
+ if (bprm->e_uid == 0 || current->uid == 0) {
+ /* pP' = (cap_bset & ~0) | (pI & ~0) */
+ bprm->cap_post_exec_permitted = cap_combine(
+ current->cap_bset, current->cap_inheritable
+ );
+ bprm->cap_effective = (bprm->e_uid == 0);
+ ret = 0;
+ }
+ }
+
+ return ret;
+}
+
+void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
+{
if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
- !cap_issubset (new_permitted, current->cap_permitted)) {
- current->mm->dumpable = suid_dumpable;
+ !cap_issubset(bprm->cap_post_exec_permitted,
+ current->cap_permitted)) {
+ set_dumpable(current->mm, suid_dumpable);
+ current->pdeath_signal = 0;
if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
if (!capable(CAP_SETUID)) {
bprm->e_uid = current->uid;
bprm->e_gid = current->gid;
}
- if (!capable (CAP_SETPCAP)) {
- new_permitted = cap_intersect (new_permitted,
- current->cap_permitted);
+ if (cap_limit_ptraced_target()) {
+ bprm->cap_post_exec_permitted = cap_intersect(
+ bprm->cap_post_exec_permitted,
+ current->cap_permitted);
}
}
}
/* For init, we want to retain the capabilities set
* in the init_task struct. Thus we skip the usual
* capability rules */
- if (current->pid != 1) {
- current->cap_permitted = new_permitted;
- current->cap_effective =
- cap_intersect (new_permitted, bprm->cap_effective);
+ if (!is_global_init(current)) {
+ current->cap_permitted = bprm->cap_post_exec_permitted;
+ if (bprm->cap_effective)
+ current->cap_effective = bprm->cap_post_exec_permitted;
+ else
+ cap_clear(current->cap_effective);
}
/* AUD: Audit candidate if current->cap_effective is set */
- current->keep_capabilities = 0;
+ current->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
}
int cap_bprm_secureexec (struct linux_binprm *bprm)
{
- /* If/when this module is enhanced to incorporate capability
- bits on files, the test below should be extended to also perform a
- test between the old and new capability sets. For now,
- it simply preserves the legacy decision algorithm used by
- the old userland. */
+ if (current->uid != 0) {
+ if (bprm->cap_effective)
+ return 1;
+ if (!cap_isclear(bprm->cap_post_exec_permitted))
+ return 1;
+ }
+
return (current->euid != current->uid ||
current->egid != current->gid);
}
-int cap_inode_setxattr(struct dentry *dentry, char *name, void *value,
- size_t size, int flags)
+int cap_inode_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
{
- if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ if (!strcmp(name, XATTR_NAME_CAPS)) {
+ if (!capable(CAP_SETFCAP))
+ return -EPERM;
+ return 0;
+ } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
sizeof(XATTR_SECURITY_PREFIX) - 1) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
}
-int cap_inode_removexattr(struct dentry *dentry, char *name)
+int cap_inode_removexattr(struct dentry *dentry, const char *name)
{
- if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ if (!strcmp(name, XATTR_NAME_CAPS)) {
+ if (!capable(CAP_SETFCAP))
+ return -EPERM;
+ return 0;
+ } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
sizeof(XATTR_SECURITY_PREFIX) - 1) &&
!capable(CAP_SYS_ADMIN))
return -EPERM;
{
if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
(current->uid != 0 && current->euid != 0 && current->suid != 0) &&
- !current->keep_capabilities) {
+ !issecure(SECURE_KEEP_CAPS)) {
cap_clear (current->cap_permitted);
cap_clear (current->cap_effective);
}
if (!issecure (SECURE_NO_SETUID_FIXUP)) {
if (old_fsuid == 0 && current->fsuid != 0) {
- cap_t (current->cap_effective) &=
- ~CAP_FS_MASK;
+ current->cap_effective =
+ cap_drop_fs_set(
+ current->cap_effective);
}
if (old_fsuid != 0 && current->fsuid == 0) {
- cap_t (current->cap_effective) |=
- (cap_t (current->cap_permitted) &
- CAP_FS_MASK);
+ current->cap_effective =
+ cap_raise_fs_set(
+ current->cap_effective,
+ current->cap_permitted);
}
}
break;
return 0;
}
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+/*
+ * Rationale: code calling task_setscheduler, task_setioprio, and
+ * task_setnice, assumes that
+ * . if capable(cap_sys_nice), then those actions should be allowed
+ * . if not capable(cap_sys_nice), but acting on your own processes,
+ * then those actions should be allowed
+ * This is insufficient now since you can call code without suid, but
+ * yet with increased caps.
+ * So we check for increased caps on the target process.
+ */
+static int cap_safe_nice(struct task_struct *p)
+{
+ if (!cap_issubset(p->cap_permitted, current->cap_permitted) &&
+ !capable(CAP_SYS_NICE))
+ return -EPERM;
+ return 0;
+}
+
+int cap_task_setscheduler (struct task_struct *p, int policy,
+ struct sched_param *lp)
+{
+ return cap_safe_nice(p);
+}
+
+int cap_task_setioprio (struct task_struct *p, int ioprio)
+{
+ return cap_safe_nice(p);
+}
+
+int cap_task_setnice (struct task_struct *p, int nice)
+{
+ return cap_safe_nice(p);
+}
+
+/*
+ * called from kernel/sys.c for prctl(PR_CABSET_DROP)
+ * done without task_capability_lock() because it introduces
+ * no new races - i.e. only another task doing capget() on
+ * this task could get inconsistent info. There can be no
+ * racing writer bc a task can only change its own caps.
+ */
+static long cap_prctl_drop(unsigned long cap)
+{
+ if (!capable(CAP_SETPCAP))
+ return -EPERM;
+ if (!cap_valid(cap))
+ return -EINVAL;
+ cap_lower(current->cap_bset, cap);
+ return 0;
+}
+
+#else
+int cap_task_setscheduler (struct task_struct *p, int policy,
+ struct sched_param *lp)
+{
+ return 0;
+}
+int cap_task_setioprio (struct task_struct *p, int ioprio)
+{
+ return 0;
+}
+int cap_task_setnice (struct task_struct *p, int nice)
+{
+ return 0;
+}
+#endif
+
+int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5, long *rc_p)
+{
+ long error = 0;
+
+ switch (option) {
+ case PR_CAPBSET_READ:
+ if (!cap_valid(arg2))
+ error = -EINVAL;
+ else
+ error = !!cap_raised(current->cap_bset, arg2);
+ break;
+#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
+ case PR_CAPBSET_DROP:
+ error = cap_prctl_drop(arg2);
+ break;
+
+ /*
+ * The next four prctl's remain to assist with transitioning a
+ * system from legacy UID=0 based privilege (when filesystem
+ * capabilities are not in use) to a system using filesystem
+ * capabilities only - as the POSIX.1e draft intended.
+ *
+ * Note:
+ *
+ * PR_SET_SECUREBITS =
+ * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
+ * | issecure_mask(SECURE_NOROOT)
+ * | issecure_mask(SECURE_NOROOT_LOCKED)
+ * | issecure_mask(SECURE_NO_SETUID_FIXUP)
+ * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
+ *
+ * will ensure that the current process and all of its
+ * children will be locked into a pure
+ * capability-based-privilege environment.
+ */
+ case PR_SET_SECUREBITS:
+ if ((((current->securebits & SECURE_ALL_LOCKS) >> 1)
+ & (current->securebits ^ arg2)) /*[1]*/
+ || ((current->securebits & SECURE_ALL_LOCKS
+ & ~arg2)) /*[2]*/
+ || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
+ || (cap_capable(current, CAP_SETPCAP) != 0)) { /*[4]*/
+ /*
+ * [1] no changing of bits that are locked
+ * [2] no unlocking of locks
+ * [3] no setting of unsupported bits
+ * [4] doing anything requires privilege (go read about
+ * the "sendmail capabilities bug")
+ */
+ error = -EPERM; /* cannot change a locked bit */
+ } else {
+ current->securebits = arg2;
+ }
+ break;
+ case PR_GET_SECUREBITS:
+ error = current->securebits;
+ break;
+
+#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
+
+ case PR_GET_KEEPCAPS:
+ if (issecure(SECURE_KEEP_CAPS))
+ error = 1;
+ break;
+ case PR_SET_KEEPCAPS:
+ if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
+ error = -EINVAL;
+ else if (issecure(SECURE_KEEP_CAPS_LOCKED))
+ error = -EPERM;
+ else if (arg2)
+ current->securebits |= issecure_mask(SECURE_KEEP_CAPS);
+ else
+ current->securebits &=
+ ~issecure_mask(SECURE_KEEP_CAPS);
+ break;
+
+ default:
+ /* No functionality available - continue with default */
+ return 0;
+ }
+
+ /* Functionality provided */
+ *rc_p = error;
+ return 1;
+}
+
void cap_task_reparent_to_init (struct task_struct *p)
{
- p->cap_effective = CAP_INIT_EFF_SET;
- p->cap_inheritable = CAP_INIT_INH_SET;
- p->cap_permitted = CAP_FULL_SET;
- p->keep_capabilities = 0;
+ cap_set_init_eff(p->cap_effective);
+ cap_clear(p->cap_inheritable);
+ cap_set_full(p->cap_permitted);
+ p->securebits = SECUREBITS_DEFAULT;
return;
}
return 0;
}
-int cap_vm_enough_memory(long pages)
+int cap_vm_enough_memory(struct mm_struct *mm, long pages)
{
int cap_sys_admin = 0;
if (cap_capable(current, CAP_SYS_ADMIN) == 0)
cap_sys_admin = 1;
- return __vm_enough_memory(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_reparent_to_init);
-EXPORT_SYMBOL(cap_syslog);
-EXPORT_SYMBOL(cap_vm_enough_memory);
-
-MODULE_DESCRIPTION("Standard Linux Common Capabilities Security Module");
-MODULE_LICENSE("GPL");
+ return __vm_enough_memory(mm, pages, cap_sys_admin);
+}
+
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff