diff options
Diffstat (limited to 'security/keys/encrypted.c')
| -rw-r--r-- | security/keys/encrypted.c | 251 |
1 files changed, 199 insertions, 52 deletions
diff --git a/security/keys/encrypted.c b/security/keys/encrypted.c index b1cba5bf0a5e..e7eca9ec4c65 100644 --- a/security/keys/encrypted.c +++ b/security/keys/encrypted.c @@ -1,8 +1,11 @@ /* * Copyright (C) 2010 IBM Corporation + * Copyright (C) 2010 Politecnico di Torino, Italy + * TORSEC group -- http://security.polito.it * - * Author: + * Authors: * Mimi Zohar <zohar@us.ibm.com> + * Roberto Sassu <roberto.sassu@polito.it> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -26,22 +29,27 @@ #include <linux/rcupdate.h> #include <linux/scatterlist.h> #include <linux/crypto.h> +#include <linux/ctype.h> #include <crypto/hash.h> #include <crypto/sha.h> #include <crypto/aes.h> #include "encrypted.h" +#include "ecryptfs_format.h" static const char KEY_TRUSTED_PREFIX[] = "trusted:"; static const char KEY_USER_PREFIX[] = "user:"; static const char hash_alg[] = "sha256"; static const char hmac_alg[] = "hmac(sha256)"; static const char blkcipher_alg[] = "cbc(aes)"; +static const char key_format_default[] = "default"; +static const char key_format_ecryptfs[] = "ecryptfs"; static unsigned int ivsize; static int blksize; #define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1) #define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1) +#define KEY_ECRYPTFS_DESC_LEN 16 #define HASH_SIZE SHA256_DIGEST_SIZE #define MAX_DATA_SIZE 4096 #define MIN_DATA_SIZE 20 @@ -58,6 +66,16 @@ enum { Opt_err = -1, Opt_new, Opt_load, Opt_update }; +enum { + Opt_error = -1, Opt_default, Opt_ecryptfs +}; + +static const match_table_t key_format_tokens = { + {Opt_default, "default"}, + {Opt_ecryptfs, "ecryptfs"}, + {Opt_error, NULL} +}; + static const match_table_t key_tokens = { {Opt_new, "new"}, {Opt_load, "load"}, @@ -82,9 +100,37 @@ static int aes_get_sizes(void) } /* + * valid_ecryptfs_desc - verify the description of a new/loaded encrypted key + * + * The description of a encrypted key with format 'ecryptfs' must contain + * exactly 16 hexadecimal characters. + * + */ +static int valid_ecryptfs_desc(const char *ecryptfs_desc) +{ + int i; + + if (strlen(ecryptfs_desc) != KEY_ECRYPTFS_DESC_LEN) { + pr_err("encrypted_key: key description must be %d hexadecimal " + "characters long\n", KEY_ECRYPTFS_DESC_LEN); + return -EINVAL; + } + + for (i = 0; i < KEY_ECRYPTFS_DESC_LEN; i++) { + if (!isxdigit(ecryptfs_desc[i])) { + pr_err("encrypted_key: key description must contain " + "only hexadecimal characters\n"); + return -EINVAL; + } + } + + return 0; +} + +/* * valid_master_desc - verify the 'key-type:desc' of a new/updated master-key * - * key-type:= "trusted:" | "encrypted:" + * key-type:= "trusted:" | "user:" * desc:= master-key description * * Verify that 'key-type' is valid and that 'desc' exists. On key update, @@ -118,8 +164,9 @@ out: * datablob_parse - parse the keyctl data * * datablob format: - * new <master-key name> <decrypted data length> - * load <master-key name> <decrypted data length> <encrypted iv + data> + * new [<format>] <master-key name> <decrypted data length> + * load [<format>] <master-key name> <decrypted data length> + * <encrypted iv + data> * update <new-master-key name> * * Tokenizes a copy of the keyctl data, returning a pointer to each token, @@ -127,52 +174,95 @@ out: * * On success returns 0, otherwise -EINVAL. */ -static int datablob_parse(char *datablob, char **master_desc, - char **decrypted_datalen, char **hex_encoded_iv) +static int datablob_parse(char *datablob, const char **format, + char **master_desc, char **decrypted_datalen, + char **hex_encoded_iv) { substring_t args[MAX_OPT_ARGS]; int ret = -EINVAL; int key_cmd; - char *p; + int key_format; + char *p, *keyword; + + keyword = strsep(&datablob, " \t"); + if (!keyword) { + pr_info("encrypted_key: insufficient parameters specified\n"); + return ret; + } + key_cmd = match_token(keyword, key_tokens, args); + /* Get optional format: default | ecryptfs */ p = strsep(&datablob, " \t"); - if (!p) + if (!p) { + pr_err("encrypted_key: insufficient parameters specified\n"); return ret; - key_cmd = match_token(p, key_tokens, args); + } - *master_desc = strsep(&datablob, " \t"); - if (!*master_desc) + key_format = match_token(p, key_format_tokens, args); + switch (key_format) { + case Opt_ecryptfs: + case Opt_default: + *format = p; + *master_desc = strsep(&datablob, " \t"); + break; + case Opt_error: + *master_desc = p; + break; + } + + if (!*master_desc) { + pr_info("encrypted_key: master key parameter is missing\n"); goto out; + } - if (valid_master_desc(*master_desc, NULL) < 0) + if (valid_master_desc(*master_desc, NULL) < 0) { + pr_info("encrypted_key: master key parameter \'%s\' " + "is invalid\n", *master_desc); goto out; + } if (decrypted_datalen) { *decrypted_datalen = strsep(&datablob, " \t"); - if (!*decrypted_datalen) + if (!*decrypted_datalen) { + pr_info("encrypted_key: keylen parameter is missing\n"); goto out; + } } switch (key_cmd) { case Opt_new: - if (!decrypted_datalen) + if (!decrypted_datalen) { + pr_info("encrypted_key: keyword \'%s\' not allowed " + "when called from .update method\n", keyword); break; + } ret = 0; break; case Opt_load: - if (!decrypted_datalen) + if (!decrypted_datalen) { + pr_info("encrypted_key: keyword \'%s\' not allowed " + "when called from .update method\n", keyword); break; + } *hex_encoded_iv = strsep(&datablob, " \t"); - if (!*hex_encoded_iv) + if (!*hex_encoded_iv) { + pr_info("encrypted_key: hex blob is missing\n"); break; + } ret = 0; break; case Opt_update: - if (decrypted_datalen) + if (decrypted_datalen) { + pr_info("encrypted_key: keyword \'%s\' not allowed " + "when called from .instantiate method\n", + keyword); break; + } ret = 0; break; case Opt_err: + pr_info("encrypted_key: keyword \'%s\' not recognized\n", + keyword); break; } out: @@ -197,8 +287,8 @@ static char *datablob_format(struct encrypted_key_payload *epayload, ascii_buf[asciiblob_len] = '\0'; /* copy datablob master_desc and datalen strings */ - len = sprintf(ascii_buf, "%s %s ", epayload->master_desc, - epayload->datalen); + len = sprintf(ascii_buf, "%s %s %s ", epayload->format, + epayload->master_desc, epayload->datalen); /* convert the hex encoded iv, encrypted-data and HMAC to ascii */ bufp = &ascii_buf[len]; @@ -378,11 +468,13 @@ static struct key *request_master_key(struct encrypted_key_payload *epayload, } else goto out; - if (IS_ERR(mkey)) + if (IS_ERR(mkey)) { pr_info("encrypted_key: key %s not found", epayload->master_desc); - if (mkey) - dump_master_key(*master_key, *master_keylen); + goto out; + } + + dump_master_key(*master_key, *master_keylen); out: return mkey; } @@ -439,9 +531,9 @@ static int datablob_hmac_append(struct encrypted_key_payload *epayload, if (ret < 0) goto out; - digest = epayload->master_desc + epayload->datablob_len; + digest = epayload->format + epayload->datablob_len; ret = calc_hmac(digest, derived_key, sizeof derived_key, - epayload->master_desc, epayload->datablob_len); + epayload->format, epayload->datablob_len); if (!ret) dump_hmac(NULL, digest, HASH_SIZE); out: @@ -450,26 +542,35 @@ out: /* verify HMAC before decrypting encrypted key */ static int datablob_hmac_verify(struct encrypted_key_payload *epayload, - const u8 *master_key, size_t master_keylen) + const u8 *format, const u8 *master_key, + size_t master_keylen) { u8 derived_key[HASH_SIZE]; u8 digest[HASH_SIZE]; int ret; + char *p; + unsigned short len; ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); if (ret < 0) goto out; - ret = calc_hmac(digest, derived_key, sizeof derived_key, - epayload->master_desc, epayload->datablob_len); + len = epayload->datablob_len; + if (!format) { + p = epayload->master_desc; + len -= strlen(epayload->format) + 1; + } else + p = epayload->format; + + ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len); if (ret < 0) goto out; - ret = memcmp(digest, epayload->master_desc + epayload->datablob_len, + ret = memcmp(digest, epayload->format + epayload->datablob_len, sizeof digest); if (ret) { ret = -EINVAL; dump_hmac("datablob", - epayload->master_desc + epayload->datablob_len, + epayload->format + epayload->datablob_len, HASH_SIZE); dump_hmac("calc", digest, HASH_SIZE); } @@ -514,13 +615,16 @@ out: /* Allocate memory for decrypted key and datablob. */ static struct encrypted_key_payload *encrypted_key_alloc(struct key *key, + const char *format, const char *master_desc, const char *datalen) { struct encrypted_key_payload *epayload = NULL; unsigned short datablob_len; unsigned short decrypted_datalen; + unsigned short payload_datalen; unsigned int encrypted_datalen; + unsigned int format_len; long dlen; int ret; @@ -528,29 +632,43 @@ static struct encrypted_key_payload *encrypted_key_alloc(struct key *key, if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE) return ERR_PTR(-EINVAL); + format_len = (!format) ? strlen(key_format_default) : strlen(format); decrypted_datalen = dlen; + payload_datalen = decrypted_datalen; + if (format && !strcmp(format, key_format_ecryptfs)) { + if (dlen != ECRYPTFS_MAX_KEY_BYTES) { + pr_err("encrypted_key: keylen for the ecryptfs format " + "must be equal to %d bytes\n", + ECRYPTFS_MAX_KEY_BYTES); + return ERR_PTR(-EINVAL); + } + decrypted_datalen = ECRYPTFS_MAX_KEY_BYTES; + payload_datalen = sizeof(struct ecryptfs_auth_tok); + } + encrypted_datalen = roundup(decrypted_datalen, blksize); - datablob_len = strlen(master_desc) + 1 + strlen(datalen) + 1 - + ivsize + 1 + encrypted_datalen; + datablob_len = format_len + 1 + strlen(master_desc) + 1 + + strlen(datalen) + 1 + ivsize + 1 + encrypted_datalen; - ret = key_payload_reserve(key, decrypted_datalen + datablob_len + ret = key_payload_reserve(key, payload_datalen + datablob_len + HASH_SIZE + 1); if (ret < 0) return ERR_PTR(ret); - epayload = kzalloc(sizeof(*epayload) + decrypted_datalen + + epayload = kzalloc(sizeof(*epayload) + payload_datalen + datablob_len + HASH_SIZE + 1, GFP_KERNEL); if (!epayload) return ERR_PTR(-ENOMEM); + epayload->payload_datalen = payload_datalen; epayload->decrypted_datalen = decrypted_datalen; epayload->datablob_len = datablob_len; return epayload; } static int encrypted_key_decrypt(struct encrypted_key_payload *epayload, - const char *hex_encoded_iv) + const char *format, const char *hex_encoded_iv) { struct key *mkey; u8 derived_key[HASH_SIZE]; @@ -571,14 +689,14 @@ static int encrypted_key_decrypt(struct encrypted_key_payload *epayload, hex2bin(epayload->iv, hex_encoded_iv, ivsize); hex2bin(epayload->encrypted_data, hex_encoded_data, encrypted_datalen); - hmac = epayload->master_desc + epayload->datablob_len; + hmac = epayload->format + epayload->datablob_len; hex2bin(hmac, hex_encoded_data + (encrypted_datalen * 2), HASH_SIZE); mkey = request_master_key(epayload, &master_key, &master_keylen); if (IS_ERR(mkey)) return PTR_ERR(mkey); - ret = datablob_hmac_verify(epayload, master_key, master_keylen); + ret = datablob_hmac_verify(epayload, format, master_key, master_keylen); if (ret < 0) { pr_err("encrypted_key: bad hmac (%d)\n", ret); goto out; @@ -598,13 +716,28 @@ out: } static void __ekey_init(struct encrypted_key_payload *epayload, - const char *master_desc, const char *datalen) + const char *format, const char *master_desc, + const char *datalen) { - epayload->master_desc = epayload->decrypted_data - + epayload->decrypted_datalen; + unsigned int format_len; + + format_len = (!format) ? strlen(key_format_default) : strlen(format); + epayload->format = epayload->payload_data + epayload->payload_datalen; + epayload->master_desc = epayload->format + format_len + 1; epayload->datalen = epayload->master_desc + strlen(master_desc) + 1; epayload->iv = epayload->datalen + strlen(datalen) + 1; epayload->encrypted_data = epayload->iv + ivsize + 1; + epayload->decrypted_data = epayload->payload_data; + + if (!format) + memcpy(epayload->format, key_format_default, format_len); + else { + if (!strcmp(format, key_format_ecryptfs)) + epayload->decrypted_data = + ecryptfs_get_auth_tok_key((struct ecryptfs_auth_tok *)epayload->payload_data); + + memcpy(epayload->format, format, format_len); + } memcpy(epayload->master_desc, master_desc, strlen(master_desc)); memcpy(epayload->datalen, datalen, strlen(datalen)); @@ -617,19 +750,29 @@ static void __ekey_init(struct encrypted_key_payload *epayload, * itself. For an old key, decrypt the hex encoded data. */ static int encrypted_init(struct encrypted_key_payload *epayload, + const char *key_desc, const char *format, const char *master_desc, const char *datalen, const char *hex_encoded_iv) { int ret = 0; - __ekey_init(epayload, master_desc, datalen); + if (format && !strcmp(format, key_format_ecryptfs)) { + ret = valid_ecryptfs_desc(key_desc); + if (ret < 0) + return ret; + + ecryptfs_fill_auth_tok((struct ecryptfs_auth_tok *)epayload->payload_data, + key_desc); + } + + __ekey_init(epayload, format, master_desc, datalen); if (!hex_encoded_iv) { get_random_bytes(epayload->iv, ivsize); get_random_bytes(epayload->decrypted_data, epayload->decrypted_datalen); } else - ret = encrypted_key_decrypt(epayload, hex_encoded_iv); + ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv); return ret; } @@ -646,6 +789,7 @@ static int encrypted_instantiate(struct key *key, const void *data, { struct encrypted_key_payload *epayload = NULL; char *datablob = NULL; + const char *format = NULL; char *master_desc = NULL; char *decrypted_datalen = NULL; char *hex_encoded_iv = NULL; @@ -659,18 +803,19 @@ static int encrypted_instantiate(struct key *key, const void *data, return -ENOMEM; datablob[datalen] = 0; memcpy(datablob, data, datalen); - ret = datablob_parse(datablob, &master_desc, &decrypted_datalen, - &hex_encoded_iv); + ret = datablob_parse(datablob, &format, &master_desc, + &decrypted_datalen, &hex_encoded_iv); if (ret < 0) goto out; - epayload = encrypted_key_alloc(key, master_desc, decrypted_datalen); + epayload = encrypted_key_alloc(key, format, master_desc, + decrypted_datalen); if (IS_ERR(epayload)) { ret = PTR_ERR(epayload); goto out; } - ret = encrypted_init(epayload, master_desc, decrypted_datalen, - hex_encoded_iv); + ret = encrypted_init(epayload, key->description, format, master_desc, + decrypted_datalen, hex_encoded_iv); if (ret < 0) { kfree(epayload); goto out; @@ -706,6 +851,7 @@ static int encrypted_update(struct key *key, const void *data, size_t datalen) struct encrypted_key_payload *new_epayload; char *buf; char *new_master_desc = NULL; + const char *format = NULL; int ret = 0; if (datalen <= 0 || datalen > 32767 || !data) @@ -717,7 +863,7 @@ static int encrypted_update(struct key *key, const void *data, size_t datalen) buf[datalen] = 0; memcpy(buf, data, datalen); - ret = datablob_parse(buf, &new_master_desc, NULL, NULL); + ret = datablob_parse(buf, &format, &new_master_desc, NULL, NULL); if (ret < 0) goto out; @@ -725,18 +871,19 @@ static int encrypted_update(struct key *key, const void *data, size_t datalen) if (ret < 0) goto out; - new_epayload = encrypted_key_alloc(key, new_master_desc, - epayload->datalen); + new_epayload = encrypted_key_alloc(key, epayload->format, + new_master_desc, epayload->datalen); if (IS_ERR(new_epayload)) { ret = PTR_ERR(new_epayload); goto out; } - __ekey_init(new_epayload, new_master_desc, epayload->datalen); + __ekey_init(new_epayload, epayload->format, new_master_desc, + epayload->datalen); memcpy(new_epayload->iv, epayload->iv, ivsize); - memcpy(new_epayload->decrypted_data, epayload->decrypted_data, - epayload->decrypted_datalen); + memcpy(new_epayload->payload_data, epayload->payload_data, + epayload->payload_datalen); rcu_assign_pointer(key->payload.data, new_epayload); call_rcu(&epayload->rcu, encrypted_rcu_free); |