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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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)
         return ret;
 
     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 */

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