LXR linux/fs/ext4/xattr

   1/*
   2 * linux/fs/ext4/xattr_security.c
   3 * Handler for storing security labels as extended attributes.
   4 */
   5
   6#include <linux/string.h>
   7#include <linux/fs.h>
   8#include <linux/security.h>
   9#include <linux/slab.h>
  10#include "ext4_jbd2.h"
  11#include "ext4.h"
  12#include "xattr.h"
  13
  14static size_t
  15ext4_xattr_security_list(const struct xattr_handler *handler,
  16                         struct dentry *dentry, char *list, size_t list_size,
  17                         const char *name, size_t name_len)
  18{
  19        const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
  20        const size_t total_len = prefix_len + name_len + 1;
  21
  22
  23        if (list && total_len <= list_size) {
  24                memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  25                memcpy(list+prefix_len, name, name_len);
  26                list[prefix_len + name_len] = '\0';
  27        }
  28        return total_len;
  29}
  30
  31static int
  32ext4_xattr_security_get(const struct xattr_handler *handler,
  33                        struct dentry *dentry, const char *name,
  34                        void *buffer, size_t size)
  35{
  36        if (strcmp(name, "") == 0)
  37                return -EINVAL;
  38        return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
  39                              name, buffer, size);
  40}
  41
  42static int
  43ext4_xattr_security_set(const struct xattr_handler *handler,
  44                        struct dentry *dentry, const char *name,
  45                        const void *value, size_t size, int flags)
  46{
  47        if (strcmp(name, "") == 0)
  48                return -EINVAL;
  49        return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
  50                              name, value, size, flags);
  51}
  52
  53static int
  54ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
  55                void *fs_info)
  56{
  57        const struct xattr *xattr;
  58        handle_t *handle = fs_info;
  59        int err = 0;
  60
  61        for (xattr = xattr_array; xattr->name != NULL; xattr++) {
  62                err = ext4_xattr_set_handle(handle, inode,
  63                                            EXT4_XATTR_INDEX_SECURITY,
  64                                            xattr->name, xattr->value,
  65                                            xattr->value_len, 0);
  66                if (err < 0)
  67                        break;
  68        }
  69        return err;
  70}
  71
  72int
  73ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
  74                   const struct qstr *qstr)
  75{
  76        return security_inode_init_security(inode, dir, qstr,
  77                                            &ext4_initxattrs, handle);
  78}
  79
  80const struct xattr_handler ext4_xattr_security_handler = {
  81        .prefix = XATTR_SECURITY_PREFIX,
  82        .list   = ext4_xattr_security_list,
  83        .get    = ext4_xattr_security_get,
  84        .set    = ext4_xattr_security_set,
  85};
  86