fs/ubifs/crypto.c

   1 #include "ubifs.h"
   2
   3 static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len)
   4 {
   5         return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
   6                                ctx, len);
   7 }
   8
   9 static int ubifs_crypt_set_context(struct inode *inode, const void *ctx,
  10                                    size_t len, void *fs_data)
  11 {
  12         return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
  13                                ctx, len, 0);
  14 }
  15
  16 static bool ubifs_crypt_empty_dir(struct inode *inode)
  17 {
  18         return ubifs_check_dir_empty(inode) == 0;
  19 }
  20
  21 static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
  22 {
  23         if (S_ISLNK(inode->i_mode))
  24                 return UBIFS_MAX_INO_DATA;
  25         else
  26                 return UBIFS_MAX_NLEN;
  27 }
  28
  29 int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
  30                   unsigned int in_len, unsigned int *out_len, int block)
  31 {
  32         struct ubifs_info *c = inode->i_sb->s_fs_info;
  33         void *p = &dn->data;
  34         struct page *ret;
  35         unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE);
  36
  37         ubifs_assert(pad_len <= *out_len);
  38         dn->compr_size = cpu_to_le16(in_len);
  39
  40         /* pad to full block cipher length */
  41         if (pad_len != in_len)
  42                 memset(p + in_len, 0, pad_len - in_len);
  43
  44         ret = fscrypt_encrypt_page(inode, virt_to_page(&dn->data), pad_len,
  45                         offset_in_page(&dn->data), block, GFP_NOFS);
  46         if (IS_ERR(ret)) {
  47                 ubifs_err(c, "fscrypt_encrypt_page failed: %ld", PTR_ERR(ret));
  48                 return PTR_ERR(ret);
  49         }
  50         *out_len = pad_len;
  51
  52         return 0;
  53 }
  54
  55 int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
  56                   unsigned int *out_len, int block)
  57 {
  58         struct ubifs_info *c = inode->i_sb->s_fs_info;
  59         int err;
  60         unsigned int clen = le16_to_cpu(dn->compr_size);
  61         unsigned int dlen = *out_len;
  62
  63         if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
  64                 ubifs_err(c, "bad compr_size: %i", clen);
  65                 return -EINVAL;
  66         }
  67
  68         ubifs_assert(dlen <= UBIFS_BLOCK_SIZE);
  69         err = fscrypt_decrypt_page(inode, virt_to_page(&dn->data), dlen,
  70                         offset_in_page(&dn->data), block);
  71         if (err) {
  72                 ubifs_err(c, "fscrypt_decrypt_page failed: %i", err);
  73                 return err;
  74         }
  75         *out_len = clen;
  76
  77         return 0;
  78 }
  79
  80 const struct fscrypt_operations ubifs_crypt_operations = {
  81         .flags                  = FS_CFLG_OWN_PAGES,
  82         .key_prefix             = "ubifs:",
  83         .get_context            = ubifs_crypt_get_context,
  84         .set_context            = ubifs_crypt_set_context,
  85         .is_encrypted           = __ubifs_crypt_is_encrypted,
  86         .empty_dir              = ubifs_crypt_empty_dir,
  87         .max_namelen            = ubifs_crypt_max_namelen,
  88 };