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-rw-r--r--security/keys/encrypted.c251
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);