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-rw-r--r--security/commoncap.c1485
1 files changed, 1485 insertions, 0 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
new file mode 100644
index 000000000..bc751fa5a
--- /dev/null
+++ b/security/commoncap.c
@@ -0,0 +1,1485 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Common capabilities, needed by capability.o.
+ */
+
+#include <linux/capability.h>
+#include <linux/audit.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/lsm_hooks.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/pagemap.h>
+#include <linux/swap.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>
+#include <linux/user_namespace.h>
+#include <linux/binfmts.h>
+#include <linux/personality.h>
+#include <linux/mnt_idmapping.h>
+
+/*
+ * If a non-root user executes a setuid-root binary in
+ * !secure(SECURE_NOROOT) mode, then we raise capabilities.
+ * However if fE is also set, then the intent is for only
+ * the file capabilities to be applied, and the setuid-root
+ * bit is left on either to change the uid (plausible) or
+ * to get full privilege on a kernel without file capabilities
+ * support. So in that case we do not raise capabilities.
+ *
+ * Warn if that happens, once per boot.
+ */
+static void warn_setuid_and_fcaps_mixed(const char *fname)
+{
+ static int warned;
+ if (!warned) {
+ printk(KERN_INFO "warning: `%s' has both setuid-root and"
+ " effective capabilities. Therefore not raising all"
+ " capabilities.\n", fname);
+ warned = 1;
+ }
+}
+
+/**
+ * cap_capable - Determine whether a task has a particular effective capability
+ * @cred: The credentials to use
+ * @targ_ns: The user namespace in which we need the capability
+ * @cap: The capability to check for
+ * @opts: Bitmask of options defined in include/linux/security.h
+ *
+ * Determine whether the nominated task has the specified capability amongst
+ * its effective set, returning 0 if it does, -ve if it does not.
+ *
+ * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable()
+ * and has_capability() functions. That is, it has the reverse semantics:
+ * cap_has_capability() returns 0 when a task has a capability, but the
+ * kernel's capable() and has_capability() returns 1 for this case.
+ */
+int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
+ int cap, unsigned int opts)
+{
+ struct user_namespace *ns = targ_ns;
+
+ /* See if cred has the capability in the target user namespace
+ * by examining the target user namespace and all of the target
+ * user namespace's parents.
+ */
+ for (;;) {
+ /* Do we have the necessary capabilities? */
+ if (ns == cred->user_ns)
+ return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
+
+ /*
+ * If we're already at a lower level than we're looking for,
+ * we're done searching.
+ */
+ if (ns->level <= cred->user_ns->level)
+ return -EPERM;
+
+ /*
+ * The owner of the user namespace in the parent of the
+ * user namespace has all caps.
+ */
+ if ((ns->parent == cred->user_ns) && uid_eq(ns->owner, cred->euid))
+ return 0;
+
+ /*
+ * If you have a capability in a parent user ns, then you have
+ * it over all children user namespaces as well.
+ */
+ ns = ns->parent;
+ }
+
+ /* We never get here */
+}
+
+/**
+ * cap_settime - Determine whether the current process may set the system clock
+ * @ts: The time to set
+ * @tz: The timezone to set
+ *
+ * Determine whether the current process may set the system clock and timezone
+ * information, returning 0 if permission granted, -ve if denied.
+ */
+int cap_settime(const struct timespec64 *ts, const struct timezone *tz)
+{
+ if (!capable(CAP_SYS_TIME))
+ return -EPERM;
+ return 0;
+}
+
+/**
+ * cap_ptrace_access_check - Determine whether the current process may access
+ * another
+ * @child: The process to be accessed
+ * @mode: The mode of attachment.
+ *
+ * If we are in the same or an ancestor user_ns and have all the target
+ * task's capabilities, then ptrace access is allowed.
+ * If we have the ptrace capability to the target user_ns, then ptrace
+ * access is allowed.
+ * Else denied.
+ *
+ * Determine whether a process may access another, returning 0 if permission
+ * granted, -ve if denied.
+ */
+int cap_ptrace_access_check(struct task_struct *child, unsigned int mode)
+{
+ int ret = 0;
+ const struct cred *cred, *child_cred;
+ const kernel_cap_t *caller_caps;
+
+ rcu_read_lock();
+ cred = current_cred();
+ child_cred = __task_cred(child);
+ if (mode & PTRACE_MODE_FSCREDS)
+ caller_caps = &cred->cap_effective;
+ else
+ caller_caps = &cred->cap_permitted;
+ if (cred->user_ns == child_cred->user_ns &&
+ cap_issubset(child_cred->cap_permitted, *caller_caps))
+ goto out;
+ if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE))
+ goto out;
+ ret = -EPERM;
+out:
+ rcu_read_unlock();
+ return ret;
+}
+
+/**
+ * cap_ptrace_traceme - Determine whether another process may trace the current
+ * @parent: The task proposed to be the tracer
+ *
+ * If parent is in the same or an ancestor user_ns and has all current's
+ * capabilities, then ptrace access is allowed.
+ * If parent has the ptrace capability to current's user_ns, then ptrace
+ * access is allowed.
+ * Else denied.
+ *
+ * Determine whether the nominated task is permitted to trace the current
+ * process, returning 0 if permission is granted, -ve if denied.
+ */
+int cap_ptrace_traceme(struct task_struct *parent)
+{
+ int ret = 0;
+ const struct cred *cred, *child_cred;
+
+ rcu_read_lock();
+ cred = __task_cred(parent);
+ child_cred = current_cred();
+ if (cred->user_ns == child_cred->user_ns &&
+ cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
+ goto out;
+ if (has_ns_capability(parent, child_cred->user_ns, CAP_SYS_PTRACE))
+ goto out;
+ ret = -EPERM;
+out:
+ rcu_read_unlock();
+ return ret;
+}
+
+/**
+ * cap_capget - Retrieve a task's capability sets
+ * @target: The task from which to retrieve the capability sets
+ * @effective: The place to record the effective set
+ * @inheritable: The place to record the inheritable set
+ * @permitted: The place to record the permitted set
+ *
+ * This function retrieves the capabilities of the nominated task and returns
+ * them to the caller.
+ */
+int cap_capget(struct task_struct *target, kernel_cap_t *effective,
+ kernel_cap_t *inheritable, kernel_cap_t *permitted)
+{
+ const struct cred *cred;
+
+ /* Derived from kernel/capability.c:sys_capget. */
+ rcu_read_lock();
+ cred = __task_cred(target);
+ *effective = cred->cap_effective;
+ *inheritable = cred->cap_inheritable;
+ *permitted = cred->cap_permitted;
+ rcu_read_unlock();
+ return 0;
+}
+
+/*
+ * Determine whether the inheritable capabilities are limited to the old
+ * permitted set. Returns 1 if they are limited, 0 if they are not.
+ */
+static inline int cap_inh_is_capped(void)
+{
+ /* they are so limited unless the current task has the CAP_SETPCAP
+ * capability
+ */
+ if (cap_capable(current_cred(), current_cred()->user_ns,
+ CAP_SETPCAP, CAP_OPT_NONE) == 0)
+ return 0;
+ return 1;
+}
+
+/**
+ * cap_capset - Validate and apply proposed changes to current's capabilities
+ * @new: The proposed new credentials; alterations should be made here
+ * @old: The current task's current credentials
+ * @effective: A pointer to the proposed new effective capabilities set
+ * @inheritable: A pointer to the proposed new inheritable capabilities set
+ * @permitted: A pointer to the proposed new permitted capabilities set
+ *
+ * This function validates and applies a proposed mass change to the current
+ * process's capability sets. The changes are made to the proposed new
+ * credentials, and assuming no error, will be committed by the caller of LSM.
+ */
+int cap_capset(struct cred *new,
+ const struct cred *old,
+ const kernel_cap_t *effective,
+ const kernel_cap_t *inheritable,
+ const kernel_cap_t *permitted)
+{
+ if (cap_inh_is_capped() &&
+ !cap_issubset(*inheritable,
+ cap_combine(old->cap_inheritable,
+ old->cap_permitted)))
+ /* incapable of using this inheritable set */
+ return -EPERM;
+
+ if (!cap_issubset(*inheritable,
+ cap_combine(old->cap_inheritable,
+ old->cap_bset)))
+ /* no new pI capabilities outside bounding set */
+ return -EPERM;
+
+ /* verify restrictions on target's new Permitted set */
+ if (!cap_issubset(*permitted, old->cap_permitted))
+ return -EPERM;
+
+ /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
+ if (!cap_issubset(*effective, *permitted))
+ return -EPERM;
+
+ new->cap_effective = *effective;
+ new->cap_inheritable = *inheritable;
+ new->cap_permitted = *permitted;
+
+ /*
+ * Mask off ambient bits that are no longer both permitted and
+ * inheritable.
+ */
+ new->cap_ambient = cap_intersect(new->cap_ambient,
+ cap_intersect(*permitted,
+ *inheritable));
+ if (WARN_ON(!cap_ambient_invariant_ok(new)))
+ return -EINVAL;
+ return 0;
+}
+
+/**
+ * cap_inode_need_killpriv - Determine if inode change affects privileges
+ * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
+ *
+ * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
+ * affects the security markings on that inode, and if it is, should
+ * inode_killpriv() be invoked or the change rejected.
+ *
+ * Return: 1 if security.capability has a value, meaning inode_killpriv()
+ * is required, 0 otherwise, meaning inode_killpriv() is not required.
+ */
+int cap_inode_need_killpriv(struct dentry *dentry)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ int error;
+
+ error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
+ return error > 0;
+}
+
+/**
+ * cap_inode_killpriv - Erase the security markings on an inode
+ *
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dentry: The inode/dentry to alter
+ *
+ * Erase the privilege-enhancing security markings on an inode.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then
+ * take care to map the inode according to @mnt_userns before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply passs init_user_ns.
+ *
+ * Return: 0 if successful, -ve on error.
+ */
+int cap_inode_killpriv(struct user_namespace *mnt_userns, struct dentry *dentry)
+{
+ int error;
+
+ error = __vfs_removexattr(mnt_userns, dentry, XATTR_NAME_CAPS);
+ if (error == -EOPNOTSUPP)
+ error = 0;
+ return error;
+}
+
+static bool rootid_owns_currentns(kuid_t kroot)
+{
+ struct user_namespace *ns;
+
+ if (!uid_valid(kroot))
+ return false;
+
+ for (ns = current_user_ns(); ; ns = ns->parent) {
+ if (from_kuid(ns, kroot) == 0)
+ return true;
+ if (ns == &init_user_ns)
+ break;
+ }
+
+ return false;
+}
+
+static __u32 sansflags(__u32 m)
+{
+ return m & ~VFS_CAP_FLAGS_EFFECTIVE;
+}
+
+static bool is_v2header(size_t size, const struct vfs_cap_data *cap)
+{
+ if (size != XATTR_CAPS_SZ_2)
+ return false;
+ return sansflags(le32_to_cpu(cap->magic_etc)) == VFS_CAP_REVISION_2;
+}
+
+static bool is_v3header(size_t size, const struct vfs_cap_data *cap)
+{
+ if (size != XATTR_CAPS_SZ_3)
+ return false;
+ return sansflags(le32_to_cpu(cap->magic_etc)) == VFS_CAP_REVISION_3;
+}
+
+/*
+ * getsecurity: We are called for security.* before any attempt to read the
+ * xattr from the inode itself.
+ *
+ * This gives us a chance to read the on-disk value and convert it. If we
+ * return -EOPNOTSUPP, then vfs_getxattr() will call the i_op handler.
+ *
+ * Note we are not called by vfs_getxattr_alloc(), but that is only called
+ * by the integrity subsystem, which really wants the unconverted values -
+ * so that's good.
+ */
+int cap_inode_getsecurity(struct user_namespace *mnt_userns,
+ struct inode *inode, const char *name, void **buffer,
+ bool alloc)
+{
+ int size, ret;
+ kuid_t kroot;
+ u32 nsmagic, magic;
+ uid_t root, mappedroot;
+ char *tmpbuf = NULL;
+ struct vfs_cap_data *cap;
+ struct vfs_ns_cap_data *nscap = NULL;
+ struct dentry *dentry;
+ struct user_namespace *fs_ns;
+
+ if (strcmp(name, "capability") != 0)
+ return -EOPNOTSUPP;
+
+ dentry = d_find_any_alias(inode);
+ if (!dentry)
+ return -EINVAL;
+
+ size = sizeof(struct vfs_ns_cap_data);
+ ret = (int)vfs_getxattr_alloc(mnt_userns, dentry, XATTR_NAME_CAPS,
+ &tmpbuf, size, GFP_NOFS);
+ dput(dentry);
+
+ if (ret < 0 || !tmpbuf) {
+ size = ret;
+ goto out_free;
+ }
+
+ fs_ns = inode->i_sb->s_user_ns;
+ cap = (struct vfs_cap_data *) tmpbuf;
+ if (is_v2header((size_t) ret, cap)) {
+ root = 0;
+ } else if (is_v3header((size_t) ret, cap)) {
+ nscap = (struct vfs_ns_cap_data *) tmpbuf;
+ root = le32_to_cpu(nscap->rootid);
+ } else {
+ size = -EINVAL;
+ goto out_free;
+ }
+
+ kroot = make_kuid(fs_ns, root);
+
+ /* If this is an idmapped mount shift the kuid. */
+ kroot = mapped_kuid_fs(mnt_userns, fs_ns, kroot);
+
+ /* If the root kuid maps to a valid uid in current ns, then return
+ * this as a nscap. */
+ mappedroot = from_kuid(current_user_ns(), kroot);
+ if (mappedroot != (uid_t)-1 && mappedroot != (uid_t)0) {
+ size = sizeof(struct vfs_ns_cap_data);
+ if (alloc) {
+ if (!nscap) {
+ /* v2 -> v3 conversion */
+ nscap = kzalloc(size, GFP_ATOMIC);
+ if (!nscap) {
+ size = -ENOMEM;
+ goto out_free;
+ }
+ nsmagic = VFS_CAP_REVISION_3;
+ magic = le32_to_cpu(cap->magic_etc);
+ if (magic & VFS_CAP_FLAGS_EFFECTIVE)
+ nsmagic |= VFS_CAP_FLAGS_EFFECTIVE;
+ memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
+ nscap->magic_etc = cpu_to_le32(nsmagic);
+ } else {
+ /* use allocated v3 buffer */
+ tmpbuf = NULL;
+ }
+ nscap->rootid = cpu_to_le32(mappedroot);
+ *buffer = nscap;
+ }
+ goto out_free;
+ }
+
+ if (!rootid_owns_currentns(kroot)) {
+ size = -EOVERFLOW;
+ goto out_free;
+ }
+
+ /* This comes from a parent namespace. Return as a v2 capability */
+ size = sizeof(struct vfs_cap_data);
+ if (alloc) {
+ if (nscap) {
+ /* v3 -> v2 conversion */
+ cap = kzalloc(size, GFP_ATOMIC);
+ if (!cap) {
+ size = -ENOMEM;
+ goto out_free;
+ }
+ magic = VFS_CAP_REVISION_2;
+ nsmagic = le32_to_cpu(nscap->magic_etc);
+ if (nsmagic & VFS_CAP_FLAGS_EFFECTIVE)
+ magic |= VFS_CAP_FLAGS_EFFECTIVE;
+ memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
+ cap->magic_etc = cpu_to_le32(magic);
+ } else {
+ /* use unconverted v2 */
+ tmpbuf = NULL;
+ }
+ *buffer = cap;
+ }
+out_free:
+ kfree(tmpbuf);
+ return size;
+}
+
+/**
+ * rootid_from_xattr - translate root uid of vfs caps
+ *
+ * @value: vfs caps value which may be modified by this function
+ * @size: size of @ivalue
+ * @task_ns: user namespace of the caller
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @fs_userns: user namespace of the filesystem
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then
+ * take care to map the inode according to @mnt_userns before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply passs init_user_ns.
+ */
+static kuid_t rootid_from_xattr(const void *value, size_t size,
+ struct user_namespace *task_ns,
+ struct user_namespace *mnt_userns,
+ struct user_namespace *fs_userns)
+{
+ const struct vfs_ns_cap_data *nscap = value;
+ kuid_t rootkid;
+ uid_t rootid = 0;
+
+ if (size == XATTR_CAPS_SZ_3)
+ rootid = le32_to_cpu(nscap->rootid);
+
+ rootkid = make_kuid(task_ns, rootid);
+ return mapped_kuid_user(mnt_userns, fs_userns, rootkid);
+}
+
+static bool validheader(size_t size, const struct vfs_cap_data *cap)
+{
+ return is_v2header(size, cap) || is_v3header(size, cap);
+}
+
+/**
+ * cap_convert_nscap - check vfs caps
+ *
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dentry: used to retrieve inode to check permissions on
+ * @ivalue: vfs caps value which may be modified by this function
+ * @size: size of @ivalue
+ *
+ * User requested a write of security.capability. If needed, update the
+ * xattr to change from v2 to v3, or to fixup the v3 rootid.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then
+ * take care to map the inode according to @mnt_userns before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply passs init_user_ns.
+ *
+ * Return: On success, return the new size; on error, return < 0.
+ */
+int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry,
+ const void **ivalue, size_t size)
+{
+ struct vfs_ns_cap_data *nscap;
+ uid_t nsrootid;
+ const struct vfs_cap_data *cap = *ivalue;
+ __u32 magic, nsmagic;
+ struct inode *inode = d_backing_inode(dentry);
+ struct user_namespace *task_ns = current_user_ns(),
+ *fs_ns = inode->i_sb->s_user_ns;
+ kuid_t rootid;
+ size_t newsize;
+
+ if (!*ivalue)
+ return -EINVAL;
+ if (!validheader(size, cap))
+ return -EINVAL;
+ if (!capable_wrt_inode_uidgid(mnt_userns, inode, CAP_SETFCAP))
+ return -EPERM;
+ if (size == XATTR_CAPS_SZ_2 && (mnt_userns == fs_ns))
+ if (ns_capable(inode->i_sb->s_user_ns, CAP_SETFCAP))
+ /* user is privileged, just write the v2 */
+ return size;
+
+ rootid = rootid_from_xattr(*ivalue, size, task_ns, mnt_userns, fs_ns);
+ if (!uid_valid(rootid))
+ return -EINVAL;
+
+ nsrootid = from_kuid(fs_ns, rootid);
+ if (nsrootid == -1)
+ return -EINVAL;
+
+ newsize = sizeof(struct vfs_ns_cap_data);
+ nscap = kmalloc(newsize, GFP_ATOMIC);
+ if (!nscap)
+ return -ENOMEM;
+ nscap->rootid = cpu_to_le32(nsrootid);
+ nsmagic = VFS_CAP_REVISION_3;
+ magic = le32_to_cpu(cap->magic_etc);
+ if (magic & VFS_CAP_FLAGS_EFFECTIVE)
+ nsmagic |= VFS_CAP_FLAGS_EFFECTIVE;
+ nscap->magic_etc = cpu_to_le32(nsmagic);
+ memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
+
+ *ivalue = nscap;
+ return newsize;
+}
+
+/*
+ * Calculate the new process capability sets from the capability sets attached
+ * to a file.
+ */
+static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
+ struct linux_binprm *bprm,
+ bool *effective,
+ bool *has_fcap)
+{
+ struct cred *new = bprm->cred;
+ unsigned i;
+ int ret = 0;
+
+ if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
+ *effective = true;
+
+ if (caps->magic_etc & VFS_CAP_REVISION_MASK)
+ *has_fcap = true;
+
+ CAP_FOR_EACH_U32(i) {
+ __u32 permitted = caps->permitted.cap[i];
+ __u32 inheritable = caps->inheritable.cap[i];
+
+ /*
+ * pP' = (X & fP) | (pI & fI)
+ * The addition of pA' is handled later.
+ */
+ new->cap_permitted.cap[i] =
+ (new->cap_bset.cap[i] & permitted) |
+ (new->cap_inheritable.cap[i] & inheritable);
+
+ if (permitted & ~new->cap_permitted.cap[i])
+ /* insufficient to execute correctly */
+ ret = -EPERM;
+ }
+
+ /*
+ * 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 *effective ? ret : 0;
+}
+
+/**
+ * get_vfs_caps_from_disk - retrieve vfs caps from disk
+ *
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dentry: dentry from which @inode is retrieved
+ * @cpu_caps: vfs capabilities
+ *
+ * Extract the on-exec-apply capability sets for an executable file.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then
+ * take care to map the inode according to @mnt_userns before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply passs init_user_ns.
+ */
+int get_vfs_caps_from_disk(struct user_namespace *mnt_userns,
+ const struct dentry *dentry,
+ struct cpu_vfs_cap_data *cpu_caps)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ __u32 magic_etc;
+ unsigned tocopy, i;
+ int size;
+ struct vfs_ns_cap_data data, *nscaps = &data;
+ struct vfs_cap_data *caps = (struct vfs_cap_data *) &data;
+ kuid_t rootkuid;
+ struct user_namespace *fs_ns;
+
+ memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
+
+ if (!inode)
+ return -ENODATA;
+
+ fs_ns = inode->i_sb->s_user_ns;
+ size = __vfs_getxattr((struct dentry *)dentry, inode,
+ XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
+ if (size == -ENODATA || size == -EOPNOTSUPP)
+ /* no data, that's ok */
+ return -ENODATA;
+
+ if (size < 0)
+ return size;
+
+ if (size < sizeof(magic_etc))
+ return -EINVAL;
+
+ cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps->magic_etc);
+
+ rootkuid = make_kuid(fs_ns, 0);
+ 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;
+ case VFS_CAP_REVISION_3:
+ if (size != XATTR_CAPS_SZ_3)
+ return -EINVAL;
+ tocopy = VFS_CAP_U32_3;
+ rootkuid = make_kuid(fs_ns, le32_to_cpu(nscaps->rootid));
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ /* Limit the caps to the mounter of the filesystem
+ * or the more limited uid specified in the xattr.
+ */
+ rootkuid = mapped_kuid_fs(mnt_userns, fs_ns, rootkuid);
+ if (!rootid_owns_currentns(rootkuid))
+ return -ENODATA;
+
+ CAP_FOR_EACH_U32(i) {
+ if (i >= tocopy)
+ break;
+ cpu_caps->permitted.cap[i] = le32_to_cpu(caps->data[i].permitted);
+ cpu_caps->inheritable.cap[i] = le32_to_cpu(caps->data[i].inheritable);
+ }
+
+ cpu_caps->permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
+ cpu_caps->inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
+
+ cpu_caps->rootid = rootkuid;
+
+ return 0;
+}
+
+/*
+ * Attempt to get the on-exec apply capability sets for an executable file from
+ * its xattrs and, if present, apply them to the proposed credentials being
+ * constructed by execve().
+ */
+static int get_file_caps(struct linux_binprm *bprm, struct file *file,
+ bool *effective, bool *has_fcap)
+{
+ int rc = 0;
+ struct cpu_vfs_cap_data vcaps;
+
+ cap_clear(bprm->cred->cap_permitted);
+
+ if (!file_caps_enabled)
+ return 0;
+
+ if (!mnt_may_suid(file->f_path.mnt))
+ return 0;
+
+ /*
+ * This check is redundant with mnt_may_suid() but is kept to make
+ * explicit that capability bits are limited to s_user_ns and its
+ * descendants.
+ */
+ if (!current_in_userns(file->f_path.mnt->mnt_sb->s_user_ns))
+ return 0;
+
+ rc = get_vfs_caps_from_disk(file_mnt_user_ns(file),
+ file->f_path.dentry, &vcaps);
+ if (rc < 0) {
+ if (rc == -EINVAL)
+ printk(KERN_NOTICE "Invalid argument reading file caps for %s\n",
+ bprm->filename);
+ else if (rc == -ENODATA)
+ rc = 0;
+ goto out;
+ }
+
+ rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective, has_fcap);
+
+out:
+ if (rc)
+ cap_clear(bprm->cred->cap_permitted);
+
+ return rc;
+}
+
+static inline bool root_privileged(void) { return !issecure(SECURE_NOROOT); }
+
+static inline bool __is_real(kuid_t uid, struct cred *cred)
+{ return uid_eq(cred->uid, uid); }
+
+static inline bool __is_eff(kuid_t uid, struct cred *cred)
+{ return uid_eq(cred->euid, uid); }
+
+static inline bool __is_suid(kuid_t uid, struct cred *cred)
+{ return !__is_real(uid, cred) && __is_eff(uid, cred); }
+
+/*
+ * handle_privileged_root - Handle case of privileged root
+ * @bprm: The execution parameters, including the proposed creds
+ * @has_fcap: Are any file capabilities set?
+ * @effective: Do we have effective root privilege?
+ * @root_uid: This namespace' root UID WRT initial USER namespace
+ *
+ * Handle the case where root is privileged and hasn't been neutered by
+ * SECURE_NOROOT. If file capabilities are set, they won't be combined with
+ * set UID root and nothing is changed. If we are root, cap_permitted is
+ * updated. If we have become set UID root, the effective bit is set.
+ */
+static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap,
+ bool *effective, kuid_t root_uid)
+{
+ const struct cred *old = current_cred();
+ struct cred *new = bprm->cred;
+
+ if (!root_privileged())
+ return;
+ /*
+ * If the legacy file capability is set, then don't set privs
+ * for a setuid root binary run by a non-root user. Do set it
+ * for a root user just to cause least surprise to an admin.
+ */
+ if (has_fcap && __is_suid(root_uid, new)) {
+ warn_setuid_and_fcaps_mixed(bprm->filename);
+ return;
+ }
+ /*
+ * To support inheritance of root-permissions and suid-root
+ * executables under compatibility mode, we override the
+ * capability sets for the file.
+ */
+ if (__is_eff(root_uid, new) || __is_real(root_uid, new)) {
+ /* pP' = (cap_bset & ~0) | (pI & ~0) */
+ new->cap_permitted = cap_combine(old->cap_bset,
+ old->cap_inheritable);
+ }
+ /*
+ * If only the real uid is 0, we do not set the effective bit.
+ */
+ if (__is_eff(root_uid, new))
+ *effective = true;
+}
+
+#define __cap_gained(field, target, source) \
+ !cap_issubset(target->cap_##field, source->cap_##field)
+#define __cap_grew(target, source, cred) \
+ !cap_issubset(cred->cap_##target, cred->cap_##source)
+#define __cap_full(field, cred) \
+ cap_issubset(CAP_FULL_SET, cred->cap_##field)
+
+static inline bool __is_setuid(struct cred *new, const struct cred *old)
+{ return !uid_eq(new->euid, old->uid); }
+
+static inline bool __is_setgid(struct cred *new, const struct cred *old)
+{ return !gid_eq(new->egid, old->gid); }
+
+/*
+ * 1) Audit candidate if current->cap_effective is set
+ *
+ * We do not bother to audit if 3 things are true:
+ * 1) cap_effective has all caps
+ * 2) we became root *OR* are were already root
+ * 3) root is supposed to have all caps (SECURE_NOROOT)
+ * Since this is just a normal root execing a process.
+ *
+ * Number 1 above might fail if you don't have a full bset, but I think
+ * that is interesting information to audit.
+ *
+ * A number of other conditions require logging:
+ * 2) something prevented setuid root getting all caps
+ * 3) non-setuid root gets fcaps
+ * 4) non-setuid root gets ambient
+ */
+static inline bool nonroot_raised_pE(struct cred *new, const struct cred *old,
+ kuid_t root, bool has_fcap)
+{
+ bool ret = false;
+
+ if ((__cap_grew(effective, ambient, new) &&
+ !(__cap_full(effective, new) &&
+ (__is_eff(root, new) || __is_real(root, new)) &&
+ root_privileged())) ||
+ (root_privileged() &&
+ __is_suid(root, new) &&
+ !__cap_full(effective, new)) ||
+ (!__is_setuid(new, old) &&
+ ((has_fcap &&
+ __cap_gained(permitted, new, old)) ||
+ __cap_gained(ambient, new, old))))
+
+ ret = true;
+
+ return ret;
+}
+
+/**
+ * cap_bprm_creds_from_file - Set up the proposed credentials for execve().
+ * @bprm: The execution parameters, including the proposed creds
+ * @file: The file to pull the credentials from
+ *
+ * Set up the proposed credentials for a new execution context being
+ * constructed by execve(). The proposed creds in @bprm->cred is altered,
+ * which won't take effect immediately.
+ *
+ * Return: 0 if successful, -ve on error.
+ */
+int cap_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file)
+{
+ /* Process setpcap binaries and capabilities for uid 0 */
+ const struct cred *old = current_cred();
+ struct cred *new = bprm->cred;
+ bool effective = false, has_fcap = false, is_setid;
+ int ret;
+ kuid_t root_uid;
+
+ if (WARN_ON(!cap_ambient_invariant_ok(old)))
+ return -EPERM;
+
+ ret = get_file_caps(bprm, file, &effective, &has_fcap);
+ if (ret < 0)
+ return ret;
+
+ root_uid = make_kuid(new->user_ns, 0);
+
+ handle_privileged_root(bprm, has_fcap, &effective, root_uid);
+
+ /* if we have fs caps, clear dangerous personality flags */
+ if (__cap_gained(permitted, new, old))
+ bprm->per_clear |= PER_CLEAR_ON_SETID;
+
+ /* Don't let someone trace a set[ug]id/setpcap binary with the revised
+ * credentials unless they have the appropriate permit.
+ *
+ * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
+ */
+ is_setid = __is_setuid(new, old) || __is_setgid(new, old);
+
+ if ((is_setid || __cap_gained(permitted, new, old)) &&
+ ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) ||
+ !ptracer_capable(current, new->user_ns))) {
+ /* downgrade; they get no more than they had, and maybe less */
+ if (!ns_capable(new->user_ns, CAP_SETUID) ||
+ (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) {
+ new->euid = new->uid;
+ new->egid = new->gid;
+ }
+ new->cap_permitted = cap_intersect(new->cap_permitted,
+ old->cap_permitted);
+ }
+
+ new->suid = new->fsuid = new->euid;
+ new->sgid = new->fsgid = new->egid;
+
+ /* File caps or setid cancels ambient. */
+ if (has_fcap || is_setid)
+ cap_clear(new->cap_ambient);
+
+ /*
+ * Now that we've computed pA', update pP' to give:
+ * pP' = (X & fP) | (pI & fI) | pA'
+ */
+ new->cap_permitted = cap_combine(new->cap_permitted, new->cap_ambient);
+
+ /*
+ * Set pE' = (fE ? pP' : pA'). Because pA' is zero if fE is set,
+ * this is the same as pE' = (fE ? pP' : 0) | pA'.
+ */
+ if (effective)
+ new->cap_effective = new->cap_permitted;
+ else
+ new->cap_effective = new->cap_ambient;
+
+ if (WARN_ON(!cap_ambient_invariant_ok(new)))
+ return -EPERM;
+
+ if (nonroot_raised_pE(new, old, root_uid, has_fcap)) {
+ ret = audit_log_bprm_fcaps(bprm, new, old);
+ if (ret < 0)
+ return ret;
+ }
+
+ new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+
+ if (WARN_ON(!cap_ambient_invariant_ok(new)))
+ return -EPERM;
+
+ /* Check for privilege-elevated exec. */
+ if (is_setid ||
+ (!__is_real(root_uid, new) &&
+ (effective ||
+ __cap_grew(permitted, ambient, new))))
+ bprm->secureexec = 1;
+
+ return 0;
+}
+
+/**
+ * cap_inode_setxattr - Determine whether an xattr may be altered
+ * @dentry: The inode/dentry being altered
+ * @name: The name of the xattr to be changed
+ * @value: The value that the xattr will be changed to
+ * @size: The size of value
+ * @flags: The replacement flag
+ *
+ * Determine whether an xattr may be altered or set on an inode, returning 0 if
+ * permission is granted, -ve if denied.
+ *
+ * This is used to make sure security xattrs don't get updated or set by those
+ * who aren't privileged to do so.
+ */
+int cap_inode_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct user_namespace *user_ns = dentry->d_sb->s_user_ns;
+
+ /* Ignore non-security xattrs */
+ if (strncmp(name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN) != 0)
+ return 0;
+
+ /*
+ * For XATTR_NAME_CAPS the check will be done in
+ * cap_convert_nscap(), called by setxattr()
+ */
+ if (strcmp(name, XATTR_NAME_CAPS) == 0)
+ return 0;
+
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+ return 0;
+}
+
+/**
+ * cap_inode_removexattr - Determine whether an xattr may be removed
+ *
+ * @mnt_userns: User namespace of the mount the inode was found from
+ * @dentry: The inode/dentry being altered
+ * @name: The name of the xattr to be changed
+ *
+ * Determine whether an xattr may be removed from an inode, returning 0 if
+ * permission is granted, -ve if denied.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then
+ * take care to map the inode according to @mnt_userns before checking
+ * permissions. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply passs init_user_ns.
+ *
+ * This is used to make sure security xattrs don't get removed by those who
+ * aren't privileged to remove them.
+ */
+int cap_inode_removexattr(struct user_namespace *mnt_userns,
+ struct dentry *dentry, const char *name)
+{
+ struct user_namespace *user_ns = dentry->d_sb->s_user_ns;
+
+ /* Ignore non-security xattrs */
+ if (strncmp(name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN) != 0)
+ return 0;
+
+ if (strcmp(name, XATTR_NAME_CAPS) == 0) {
+ /* security.capability gets namespaced */
+ struct inode *inode = d_backing_inode(dentry);
+ if (!inode)
+ return -EINVAL;
+ if (!capable_wrt_inode_uidgid(mnt_userns, inode, CAP_SETFCAP))
+ return -EPERM;
+ return 0;
+ }
+
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+ return 0;
+}
+
+/*
+ * cap_emulate_setxuid() fixes the effective / permitted capabilities of
+ * a process after a call to setuid, setreuid, or setresuid.
+ *
+ * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
+ * {r,e,s}uid != 0, the permitted and effective capabilities are
+ * cleared.
+ *
+ * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
+ * capabilities of the process are cleared.
+ *
+ * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
+ * capabilities are set to the permitted capabilities.
+ *
+ * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
+ * never happen.
+ *
+ * -astor
+ *
+ * cevans - New behaviour, Oct '99
+ * A process may, via prctl(), elect to keep its capabilities when it
+ * calls setuid() and switches away from uid==0. Both permitted and
+ * effective sets will be retained.
+ * Without this change, it was impossible for a daemon to drop only some
+ * of its privilege. The call to setuid(!=0) would drop all privileges!
+ * Keeping uid 0 is not an option because uid 0 owns too many vital
+ * files..
+ * Thanks to Olaf Kirch and Peter Benie for spotting this.
+ */
+static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
+{
+ kuid_t root_uid = make_kuid(old->user_ns, 0);
+
+ if ((uid_eq(old->uid, root_uid) ||
+ uid_eq(old->euid, root_uid) ||
+ uid_eq(old->suid, root_uid)) &&
+ (!uid_eq(new->uid, root_uid) &&
+ !uid_eq(new->euid, root_uid) &&
+ !uid_eq(new->suid, root_uid))) {
+ if (!issecure(SECURE_KEEP_CAPS)) {
+ cap_clear(new->cap_permitted);
+ cap_clear(new->cap_effective);
+ }
+
+ /*
+ * Pre-ambient programs expect setresuid to nonroot followed
+ * by exec to drop capabilities. We should make sure that
+ * this remains the case.
+ */
+ cap_clear(new->cap_ambient);
+ }
+ if (uid_eq(old->euid, root_uid) && !uid_eq(new->euid, root_uid))
+ cap_clear(new->cap_effective);
+ if (!uid_eq(old->euid, root_uid) && uid_eq(new->euid, root_uid))
+ new->cap_effective = new->cap_permitted;
+}
+
+/**
+ * cap_task_fix_setuid - Fix up the results of setuid() call
+ * @new: The proposed credentials
+ * @old: The current task's current credentials
+ * @flags: Indications of what has changed
+ *
+ * Fix up the results of setuid() call before the credential changes are
+ * actually applied.
+ *
+ * Return: 0 to grant the changes, -ve to deny them.
+ */
+int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
+{
+ switch (flags) {
+ case LSM_SETID_RE:
+ case LSM_SETID_ID:
+ case LSM_SETID_RES:
+ /* juggle the capabilities to follow [RES]UID changes unless
+ * otherwise suppressed */
+ if (!issecure(SECURE_NO_SETUID_FIXUP))
+ cap_emulate_setxuid(new, old);
+ break;
+
+ case LSM_SETID_FS:
+ /* juggle the capabilties to follow FSUID changes, unless
+ * otherwise suppressed
+ *
+ * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
+ * if not, we might be a bit too harsh here.
+ */
+ if (!issecure(SECURE_NO_SETUID_FIXUP)) {
+ kuid_t root_uid = make_kuid(old->user_ns, 0);
+ if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid))
+ new->cap_effective =
+ cap_drop_fs_set(new->cap_effective);
+
+ if (!uid_eq(old->fsuid, root_uid) && uid_eq(new->fsuid, root_uid))
+ new->cap_effective =
+ cap_raise_fs_set(new->cap_effective,
+ new->cap_permitted);
+ }
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * 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)
+{
+ int is_subset, ret = 0;
+
+ rcu_read_lock();
+ is_subset = cap_issubset(__task_cred(p)->cap_permitted,
+ current_cred()->cap_permitted);
+ if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE))
+ ret = -EPERM;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+/**
+ * cap_task_setscheduler - Detemine if scheduler policy change is permitted
+ * @p: The task to affect
+ *
+ * Detemine if the requested scheduler policy change is permitted for the
+ * specified task.
+ *
+ * Return: 0 if permission is granted, -ve if denied.
+ */
+int cap_task_setscheduler(struct task_struct *p)
+{
+ return cap_safe_nice(p);
+}
+
+/**
+ * cap_task_setioprio - Detemine if I/O priority change is permitted
+ * @p: The task to affect
+ * @ioprio: The I/O priority to set
+ *
+ * Detemine if the requested I/O priority change is permitted for the specified
+ * task.
+ *
+ * Return: 0 if permission is granted, -ve if denied.
+ */
+int cap_task_setioprio(struct task_struct *p, int ioprio)
+{
+ return cap_safe_nice(p);
+}
+
+/**
+ * cap_task_setnice - Detemine if task priority change is permitted
+ * @p: The task to affect
+ * @nice: The nice value to set
+ *
+ * Detemine if the requested task priority change is permitted for the
+ * specified task.
+ *
+ * Return: 0 if permission is granted, -ve if denied.
+ */
+int cap_task_setnice(struct task_struct *p, int nice)
+{
+ return cap_safe_nice(p);
+}
+
+/*
+ * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
+ * the current task's bounding set. Returns 0 on success, -ve on error.
+ */
+static int cap_prctl_drop(unsigned long cap)
+{
+ struct cred *new;
+
+ if (!ns_capable(current_user_ns(), CAP_SETPCAP))
+ return -EPERM;
+ if (!cap_valid(cap))
+ return -EINVAL;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+ cap_lower(new->cap_bset, cap);
+ return commit_creds(new);
+}
+
+/**
+ * cap_task_prctl - Implement process control functions for this security module
+ * @option: The process control function requested
+ * @arg2: The argument data for this function
+ * @arg3: The argument data for this function
+ * @arg4: The argument data for this function
+ * @arg5: The argument data for this function
+ *
+ * Allow process control functions (sys_prctl()) to alter capabilities; may
+ * also deny access to other functions not otherwise implemented here.
+ *
+ * Return: 0 or +ve on success, -ENOSYS if this function is not implemented
+ * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
+ * modules will consider performing the function.
+ */
+int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5)
+{
+ const struct cred *old = current_cred();
+ struct cred *new;
+
+ switch (option) {
+ case PR_CAPBSET_READ:
+ if (!cap_valid(arg2))
+ return -EINVAL;
+ return !!cap_raised(old->cap_bset, arg2);
+
+ case PR_CAPBSET_DROP:
+ return cap_prctl_drop(arg2);
+
+ /*
+ * 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 ((((old->securebits & SECURE_ALL_LOCKS) >> 1)
+ & (old->securebits ^ arg2)) /*[1]*/
+ || ((old->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/
+ || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
+ || (cap_capable(current_cred(),
+ current_cred()->user_ns,
+ CAP_SETPCAP,
+ CAP_OPT_NONE) != 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")
+ */
+ )
+ /* cannot change a locked bit */
+ return -EPERM;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+ new->securebits = arg2;
+ return commit_creds(new);
+
+ case PR_GET_SECUREBITS:
+ return old->securebits;
+
+ case PR_GET_KEEPCAPS:
+ return !!issecure(SECURE_KEEP_CAPS);
+
+ case PR_SET_KEEPCAPS:
+ if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
+ return -EINVAL;
+ if (issecure(SECURE_KEEP_CAPS_LOCKED))
+ return -EPERM;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+ if (arg2)
+ new->securebits |= issecure_mask(SECURE_KEEP_CAPS);
+ else
+ new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+ return commit_creds(new);
+
+ case PR_CAP_AMBIENT:
+ if (arg2 == PR_CAP_AMBIENT_CLEAR_ALL) {
+ if (arg3 | arg4 | arg5)
+ return -EINVAL;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+ cap_clear(new->cap_ambient);
+ return commit_creds(new);
+ }
+
+ if (((!cap_valid(arg3)) | arg4 | arg5))
+ return -EINVAL;
+
+ if (arg2 == PR_CAP_AMBIENT_IS_SET) {
+ return !!cap_raised(current_cred()->cap_ambient, arg3);
+ } else if (arg2 != PR_CAP_AMBIENT_RAISE &&
+ arg2 != PR_CAP_AMBIENT_LOWER) {
+ return -EINVAL;
+ } else {
+ if (arg2 == PR_CAP_AMBIENT_RAISE &&
+ (!cap_raised(current_cred()->cap_permitted, arg3) ||
+ !cap_raised(current_cred()->cap_inheritable,
+ arg3) ||
+ issecure(SECURE_NO_CAP_AMBIENT_RAISE)))
+ return -EPERM;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+ if (arg2 == PR_CAP_AMBIENT_RAISE)
+ cap_raise(new->cap_ambient, arg3);
+ else
+ cap_lower(new->cap_ambient, arg3);
+ return commit_creds(new);
+ }
+
+ default:
+ /* No functionality available - continue with default */
+ return -ENOSYS;
+ }
+}
+
+/**
+ * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
+ * @mm: The VM space in which the new mapping is to be made
+ * @pages: The size of the mapping
+ *
+ * Determine whether the allocation of a new virtual mapping by the current
+ * task is permitted.
+ *
+ * Return: 1 if permission is granted, 0 if not.
+ */
+int cap_vm_enough_memory(struct mm_struct *mm, long pages)
+{
+ int cap_sys_admin = 0;
+
+ if (cap_capable(current_cred(), &init_user_ns,
+ CAP_SYS_ADMIN, CAP_OPT_NOAUDIT) == 0)
+ cap_sys_admin = 1;
+
+ return cap_sys_admin;
+}
+
+/**
+ * cap_mmap_addr - check if able to map given addr
+ * @addr: address attempting to be mapped
+ *
+ * If the process is attempting to map memory below dac_mmap_min_addr they need
+ * CAP_SYS_RAWIO. The other parameters to this function are unused by the
+ * capability security module.
+ *
+ * Return: 0 if this mapping should be allowed or -EPERM if not.
+ */
+int cap_mmap_addr(unsigned long addr)
+{
+ int ret = 0;
+
+ if (addr < dac_mmap_min_addr) {
+ ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO,
+ CAP_OPT_NONE);
+ /* set PF_SUPERPRIV if it turns out we allow the low mmap */
+ if (ret == 0)
+ current->flags |= PF_SUPERPRIV;
+ }
+ return ret;
+}
+
+int cap_mmap_file(struct file *file, unsigned long reqprot,
+ unsigned long prot, unsigned long flags)
+{
+ return 0;
+}
+
+#ifdef CONFIG_SECURITY
+
+static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
+ LSM_HOOK_INIT(capable, cap_capable),
+ LSM_HOOK_INIT(settime, cap_settime),
+ LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check),
+ LSM_HOOK_INIT(ptrace_traceme, cap_ptrace_traceme),
+ LSM_HOOK_INIT(capget, cap_capget),
+ LSM_HOOK_INIT(capset, cap_capset),
+ LSM_HOOK_INIT(bprm_creds_from_file, cap_bprm_creds_from_file),
+ LSM_HOOK_INIT(inode_need_killpriv, cap_inode_need_killpriv),
+ LSM_HOOK_INIT(inode_killpriv, cap_inode_killpriv),
+ LSM_HOOK_INIT(inode_getsecurity, cap_inode_getsecurity),
+ LSM_HOOK_INIT(mmap_addr, cap_mmap_addr),
+ LSM_HOOK_INIT(mmap_file, cap_mmap_file),
+ LSM_HOOK_INIT(task_fix_setuid, cap_task_fix_setuid),
+ LSM_HOOK_INIT(task_prctl, cap_task_prctl),
+ LSM_HOOK_INIT(task_setscheduler, cap_task_setscheduler),
+ LSM_HOOK_INIT(task_setioprio, cap_task_setioprio),
+ LSM_HOOK_INIT(task_setnice, cap_task_setnice),
+ LSM_HOOK_INIT(vm_enough_memory, cap_vm_enough_memory),
+};
+
+static int __init capability_init(void)
+{
+ security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks),
+ "capability");
+ return 0;
+}
+
+DEFINE_LSM(capability) = {
+ .name = "capability",
+ .order = LSM_ORDER_FIRST,
+ .init = capability_init,
+};
+
+#endif /* CONFIG_SECURITY */