diff options
| -rw-r--r-- | ubifs-utils/mkfs.ubifs/mkfs.ubifs.c | 75 |
1 files changed, 68 insertions, 7 deletions
diff --git a/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c b/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c index c315e36..4ffd8fd 100644 --- a/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c +++ b/ubifs-utils/mkfs.ubifs/mkfs.ubifs.c @@ -155,6 +155,16 @@ struct fscrypt_context { __u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; } __attribute__((packed)); +/** + * For encrypted symlinks, the ciphertext length is stored at the beginning + * of the string in little-endian format. + */ +struct fscrypt_symlink_data { + __le16 len; + char encrypted_path[1]; +} __attribute__((packed)); + + #ifndef FS_MAX_KEY_SIZE #define FS_MAX_KEY_SIZE 64 #endif @@ -578,15 +588,22 @@ static struct fscrypt_context *init_fscrypt_context(void) new_fctx->format = FS_ENCRYPTION_CONTEXT_FORMAT_V1; new_fctx->contents_encryption_mode = FS_ENCRYPTION_MODE_AES_128_CBC; new_fctx->filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_128_CTS; - //TODO accept padding via a parameter new_fctx->flags = FS_POLICY_FLAGS_PAD_4; - //TODO accept descriptor via a parameter - RAND_bytes((void *)&new_fctx->master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE); RAND_bytes((void *)&new_fctx->nonce, FS_KEY_DERIVATION_NONCE_SIZE); return new_fctx; } +unsigned int fscrypt_fname_encrypted_size(struct fscrypt_context *fctx, unsigned int ilen) +{ + int padding; + + padding = 4 << (fctx->flags & FS_POLICY_FLAGS_PAD_MASK); + ilen = max_t(unsigned int, ilen, FS_CRYPTO_BLOCK_SIZE); + return round_up(ilen, padding); +} + + /** * open_ubi - open the UBI volume. * @node: name of the UBI volume character device to fetch information about @@ -1478,11 +1495,54 @@ static int add_inode(struct stat *st, ino_t inum, void *data, ino->gid = cpu_to_le32(st->st_gid); ino->mode = cpu_to_le32(st->st_mode); ino->flags = cpu_to_le32(use_flags); - ino->data_len = cpu_to_le32(data_len); ino->compr_type = cpu_to_le16(c->default_compr); - if (data_len) - memcpy(&ino->data, data, data_len); + if (data_len) { + if (!S_ISLNK(st->st_mode)) + return err_msg("Expected symlink"); + if (!fctx) { + memcpy(&ino->data, data, data_len); + } else { + //TODO turn this into a common helper + struct fscrypt_symlink_data *sd; + void *inbuf, *outbuf, *crypt_key; + unsigned int max_namelen = UBIFS_MAX_INO_DATA; + unsigned int padding = 4 << (fctx->flags & FS_POLICY_FLAGS_PAD_MASK); + unsigned int cryptlen; + unsigned int link_disk_len = fscrypt_fname_encrypted_size(fctx, data_len) + sizeof(struct fscrypt_symlink_data); + + cryptlen = max_t(unsigned int, data_len, FS_CRYPTO_BLOCK_SIZE); + cryptlen = round_up(cryptlen, padding); + cryptlen = min(cryptlen, max_namelen); + + sd = xzalloc(link_disk_len); + inbuf = xmalloc(cryptlen); + /* CTS mode needs a block size aligned buffer */ + outbuf = xmalloc(round_up(cryptlen, FS_CRYPTO_BLOCK_SIZE)); + + memset(inbuf, 0, cryptlen); + memcpy(inbuf, data, data_len); + + crypt_key = calc_fscrypt_subkey(fctx); + if (!crypt_key) + return err_msg("could not compute subkey"); + if (encrypt_aes128_cbc_cts(inbuf, cryptlen, crypt_key, outbuf) < 0) + return err_msg("could not encrypt filename"); + + memcpy(sd->encrypted_path, outbuf, cryptlen); + sd->len = cpu_to_le16(cryptlen); + memcpy(&ino->data, sd, link_disk_len); + ((char *)&ino->data)[link_disk_len - 1] = '\0'; + + data_len = link_disk_len; + + free(crypt_key); + free(inbuf); + free(outbuf); + free(sd); + } + } + ino->data_len = cpu_to_le32(data_len); len = UBIFS_INO_NODE_SZ + data_len; if (xattr_path) { @@ -1635,7 +1695,8 @@ static int add_dent_node(ino_t dir_inum, const char *name, ino_t inum, cryptlen = min(cryptlen, max_namelen); inbuf = xmalloc(cryptlen); - outbuf = xmalloc(cryptlen + 32); + /* CTS mode needs a block size aligned buffer */ + outbuf = xmalloc(round_up(cryptlen, FS_CRYPTO_BLOCK_SIZE)); memset(inbuf, 0, cryptlen); memcpy(inbuf, dname.name, dname.len); |