3 files changed, 142 insertions, 60 deletions

diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt
index 8fb79bc1ac4b..0afcb5023c75 100644
--- a/Documentation/security/keys-trusted-encrypted.txt
+++ b/Documentation/security/keys-trusted-encrypted.txt
@@ -53,12 +53,19 @@ they are only as secure as the user key encrypting them.  The master user key
 should therefore be loaded in as secure a way as possible, preferably early in
 boot.
 
+The decrypted portion of encrypted keys can contain either a simple symmetric
+key or a more complex structure. The format of the more complex structure is
+application specific, which is identified by 'format'.
+
 Usage:
-  keyctl add encrypted name "new key-type:master-key-name keylen" ring
-  keyctl add encrypted name "load hex_blob" ring
-  keyctl update keyid "update key-type:master-key-name"
+    keyctl add encrypted name "new [format] key-type:master-key-name keylen"
+        ring
+    keyctl add encrypted name "load hex_blob" ring
+    keyctl update keyid "update key-type:master-key-name"
+
+format:= 'default'
+key-type:= 'trusted' | 'user'
 
-where 'key-type' is either 'trusted' or 'user'.
 
 Examples of trusted and encrypted key usage:
 
@@ -114,15 +121,25 @@ Reseal a trusted key under new pcr values:
     7ef6a24defe4846104209bf0c3eced7fa1a672ed5b125fc9d8cd88b476a658a4434644ef
     df8ae9a178e9f83ba9f08d10fa47e4226b98b0702f06b3b8
 
-Create and save an encrypted key "evm" using the above trusted key "kmk":
+The initial consumer of trusted keys is EVM, which at boot time needs a high
+quality symmetric key for HMAC protection of file metadata.  The use of a
+trusted key provides strong guarantees that the EVM key has not been
+compromised by a user level problem, and when sealed to specific boot PCR
+values, protects against boot and offline attacks.  Create and save an
+encrypted key "evm" using the above trusted key "kmk":
 
+option 1: omitting 'format'
     $ keyctl add encrypted evm "new trusted:kmk 32" @u
     159771175
 
+option 2: explicitly defining 'format' as 'default'
+    $ keyctl add encrypted evm "new default trusted:kmk 32" @u
+    159771175
+
     $ keyctl print 159771175
-    trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b382dbbc55
-    be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e024717c64
-    5972dcb82ab2dde83376d82b2e3c09ffc
+    default trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b3
+    82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0
+    24717c64 5972dcb82ab2dde83376d82b2e3c09ffc
 
     $ keyctl pipe 159771175 > evm.blob
 
@@ -132,14 +149,9 @@ Load an encrypted key "evm" from saved blob:
     831684262
 
     $ keyctl print 831684262
-    trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b382dbbc55
-    be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e024717c64
-    5972dcb82ab2dde83376d82b2e3c09ffc
-
+    default trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b3
+    82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0
+    24717c64 5972dcb82ab2dde83376d82b2e3c09ffc
 
-The initial consumer of trusted keys is EVM, which at boot time needs a high
-quality symmetric key for HMAC protection of file metadata.  The use of a
-trusted key provides strong guarantees that the EVM key has not been
-compromised by a user level problem, and when sealed to specific boot PCR
-values, protects against boot and offline attacks.  Other uses for trusted and
-encrypted keys, such as for disk and file encryption are anticipated.
+Other uses for trusted and encrypted keys, such as for disk and file encryption
+are anticipated.
diff --git a/include/keys/encrypted-type.h b/include/keys/encrypted-type.h
index 95855017a32b..1d4541370a64 100644
--- a/include/keys/encrypted-type.h
+++ b/include/keys/encrypted-type.h
@@ -1,6 +1,11 @@
 /*
  * Copyright (C) 2010 IBM Corporation
- * Author: Mimi Zohar <zohar@us.ibm.com>
+ * Copyright (C) 2010 Politecnico di Torino, Italy
+ *                    TORSEC group -- http://security.polito.it
+ *
+ * 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
@@ -15,13 +20,17 @@
 
 struct encrypted_key_payload {
         struct rcu_head rcu;
+        char *format;           /* datablob: format */
         char *master_desc;      /* datablob: master key name */
         char *datalen;          /* datablob: decrypted key length */
         u8 *iv;                 /* datablob: iv */
         u8 *encrypted_data;     /* datablob: encrypted data */
         unsigned short datablob_len;    /* length of datablob */
         unsigned short decrypted_datalen;       /* decrypted data length */
-        u8 decrypted_data[0];   /* decrypted data +  datablob + hmac */
+        unsigned short payload_datalen;         /* payload data length */
+        unsigned short encrypted_key_format;    /* encrypted key format */
+        u8 *decrypted_data;     /* decrypted data */
+        u8 payload_data[0];     /* payload data + datablob + hmac */
 };
 
 extern struct key_type key_type_encrypted;
diff --git a/security/keys/encrypted.c b/security/keys/encrypted.c
index f36a105de791..89981c987ba7 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
@@ -37,6 +40,7 @@ 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 unsigned int ivsize;
 static int blksize;
 
@@ -58,6 +62,15 @@ enum {
         Opt_err = -1, Opt_new, Opt_load, Opt_update
 };
 
+enum {
+        Opt_error = -1, Opt_default
+};
+
+static const match_table_t key_format_tokens = {
+        {Opt_default, "default"},
+        {Opt_error, NULL}
+};
+
 static const match_table_t key_tokens = {
         {Opt_new, "new"},
         {Opt_load, "load"},
@@ -118,8 +131,9 @@ 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,
@@ -127,13 +141,15 @@ 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 *keyword;
+        int key_format;
+        char *p, *keyword;
 
         keyword = strsep(&datablob, " \t");
         if (!keyword) {
@@ -142,7 +158,24 @@ static int datablob_parse(char *datablob, char **master_desc,
         }
         key_cmd = match_token(keyword, key_tokens, args);
 
-        *master_desc = strsep(&datablob, " \t");
+        /* Get optional format: default */
+        p = strsep(&datablob, " \t");
+        if (!p) {
+                pr_err("encrypted_key: insufficient parameters specified\n");
+                return ret;
+        }
+
+        key_format = match_token(p, key_format_tokens, args);
+        switch (key_format) {
+        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;
@@ -220,8 +253,8 @@ 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];
@@ -464,9 +497,9 @@ 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:
@@ -475,26 +508,35 @@ 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);
         }
@@ -539,13 +581,16 @@ 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;
 
@@ -553,29 +598,32 @@ 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;
         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];
@@ -596,14 +644,14 @@ 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;
@@ -623,14 +671,23 @@ 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
+                memcpy(epayload->format, format, format_len);
         memcpy(epayload->master_desc, master_desc, strlen(master_desc));
         memcpy(epayload->datalen, datalen, strlen(datalen));
 }
@@ -642,19 +699,19 @@ 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 *master_desc, const char *datalen,
-                          const char *hex_encoded_iv)
+                          const char *format, const char *master_desc,
+                          const char *datalen, const char *hex_encoded_iv)
 {
         int ret = 0;
 
-        __ekey_init(epayload, master_desc, datalen);
+        __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;
 }
 
@@ -671,6 +728,7 @@ 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;
@@ -684,17 +742,18 @@ 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,
+        ret = encrypted_init(epayload, format, master_desc, decrypted_datalen,
                              hex_encoded_iv);
         if (ret < 0) {
                 kfree(epayload);
@@ -731,6 +790,7 @@ 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)
@@ -742,7 +802,7 @@ 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;
 
@@ -750,18 +810,19 @@ 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);