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/****************************************************************
* *
* Copyright 2009, 2014 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#ifndef GTMCRYPT_DBK_REF_H
#define GTMCRYPT_DBK_REF_H
/*
* This file defines several structures that store information about every symmetric key that we load as well the encryption /
* decryption context for any database or device that uses that particular key. The information about the key includes its raw
* content and its hash; those are stored in gtm_keystore_t->typed objects malloced invdividually. To assist lookups based on the
* key's hash or name, we have tree structures consisting of gtm_keystore_hash_link_t- and gtm_keystore_keyname_link_t-typed nodes,
* respectively. Since we expect hashes to be unique, and the hash information is already stored in gtm_keystore_t nodes, the hash-
* based tree's nodes contain no additional information and have a one-to-one and onto relationship with the gtm_keystore_t nodes.
* The keyname-based tree's nodes, on the other hand, also contain the key name information, which may correspond to the database's
* name or a user-chosen string, in case of device encryption. Additionally, several databases or devices may use the same key, in
* which case one gtm_keystore_t element may be referenced by multiple keyname tree's nodes. An example is given below:
*
* keystore_by_hash_head keystore_by_keyname_head
* (gtm_keystore_hash_link_t *) (gtm_keystore_t *) (gtm_keystore_keyname_link_t *)
* | ________ |
* ______|_____ | | ______|_____
* | link ---|-------------> | key #1 | <-----. .------------|--- link |
* | left right | |________| \ / | left right |
* |_/_______\__| \/ |_/_______\__|
* / \ ________ /\ / \
* _______/____ \ | | / \ ______/_____ \
* | link ---|-------\-------------> | key #2 | <-----` `-----|--- link | \
* | left right | \ |________| | left right | \
* |_/_______\__| \ |_/_______\__| \
* ... ... \ ________ / ... \
* _____\______ | | / _____\______
* | link ---|--> | key #3 | <-.------------ / -----------------|--- link |
* | left right | |________| \ / | left right |
* |_/_______\__| \ ______/_____ |_/_______\__|
* ... ... `-|--- link | ... ...
* | left right |
* |_/_______\__|
* ... ...
*
* Because we resolve database file names' real paths when we read the configuration file, it is possible that one or more databases
* might not yet exist (such as when issuing MUPIP CREATE), so we temporarily store whatever information we processed in an
* unresolved databases' list, hoping that a later attempt of resolving the path will succeed. The list is singly-linked and consist
* of gtm_keystore_keyname_link_t-typed elements; each element contains information about the key name, raw content, and hash.
*
* As for gtm_keystore_t elements, in addition to the key data they host a pointer to the head of the encryption / decryption state
* list as well as to the one element of that list that is specific to database encryption. (Because database encryption does not
* preserve its state beyond one block, we only ever create one database encryption and one database decryption state object, which
* gets reused continuously.) Unlike devices, which can activate encryption and decryption individually, databases have to have both
* encryption and decryption enabled at once. For that reason, if there is a database encryption context entry in one key's contexts
* list, there is a database decryption context right after.
*
* The encryption / decryption contexts list is doubly-linked and consists of gtm_cipher_ctx_t-typed elements. Each element contains
* the algorithm-specific (such as OpenSSL or GCRYPT) encryption or decryption state object, initialization vector (used only when
* initializing the encryption / decryption state) and a pointer back to its respective key structure. An example is given below:
*
* ____________________________________________
* | cipher_head db_cipher_entry |
* .---> | (gtm_cipher_ctx_t *) (gtm_cipher_ctx_t *) |
* | |___/__________________________|_____________|
* | / |
* | / (DB ENCR) ---> (DB DECR)
* | ____/____ _________ ____|____ _________
* | | prev | <--|- prev | <--|- prev | <--|- prev |
* | | next --|--> | next --|--> | next --|--> | next |
* | | store | | store | | store | | store |
* | |____|____| |____|____| |____|____| |____|____|
* | | | | |
* `-------'--------------'--------------'--------------`
*
* For the actual implementation of the above design please refer to gtmcrypt_dbk_ref.c.
*/
/* Principal structure for storing key information required to perform encryption / decryption. */
typedef struct gtm_keystore_struct
{
unsigned char key[SYMMETRIC_KEY_MAX]; /* Raw symmetric key contents. */
unsigned char key_hash[GTMCRYPT_HASH_LEN]; /* SHA-512 hash of symmetric key. */
struct gtm_cipher_ctx_struct *cipher_head; /* Linked list of cipher handles for
* either encryption or decryption. A list
* is needed because multiple devices or
* databases can map to the same key, but
* the internal encryption / decryption
* state cannot be shared. */
struct gtm_cipher_ctx_struct *db_cipher_entry; /* Direct pointer to the (only) DB
* encryption cipher entry (followed by the
* DB decryption entry). */
} gtm_keystore_t;
/* Structure for storing the encryption / decryption state for one device or any DB using the key pointed to by the store field. */
typedef struct gtm_cipher_ctx_struct
{
crypt_key_t handle; /* Encryption / decryption state. */
unsigned char iv[GTMCRYPT_IV_LEN]; /* Initialization vector. */
gtm_keystore_t *store; /* Pointer to master key object. */
struct gtm_cipher_ctx_struct *prev; /* Pointer to previous element. */
struct gtm_cipher_ctx_struct *next; /* Pointer to next element. */
} gtm_cipher_ctx_t;
/* Structure to organize references to the key object by the key name, in a binary search tree fashion. */
typedef struct gtm_keystore_keyname_link_struct
{
gtm_keystore_t *link; /* Link to respective key object. */
char key_name[GTM_PATH_MAX]; /* Logical entity that the symmetric key
* maps to. For databases it is the name of
* the database file. For devices it is a
* user-chosen string. */
struct gtm_keystore_keyname_link_struct *left; /* Pointer to left child. */
struct gtm_keystore_keyname_link_struct *right; /* Pointer to right child. */
} gtm_keystore_keyname_link_t;
/* Structure to organize references to the key object by the key hash, in a binary search tree fashion. */
typedef struct gtm_keystore_hash_link_struct
{
gtm_keystore_t *link; /* Link to respective key object. */
struct gtm_keystore_hash_link_struct *left; /* Pointer to left child. */
struct gtm_keystore_hash_link_struct *right; /* Pointer to right child. */
} gtm_keystore_hash_link_t;
/* Structure to temporarily store key information if the real path of the respective database file name could not be obtained. */
typedef struct gtm_keystore_unres_keyname_link_struct
{
unsigned char key[SYMMETRIC_KEY_MAX]; /* Raw symmetric key contents. */
unsigned char key_hash[GTMCRYPT_HASH_LEN]; /* SHA-512 hash of symmetric key. */
char key_name[GTM_PATH_MAX]; /* Logical entity that the symmetric key
* maps to. For databases it is the name of
* the database file. For devices it is a
* user-chosen string. */
struct gtm_keystore_unres_keyname_link_struct *next; /* Pointer to next element. */
} gtm_keystore_unres_keyname_link_t;
STATICFNDEF int keystore_refresh(int *new_db_keys, int *new_db_hashes, int *new_dev_keys, int *new_dev_hashes);
STATICFNDEF int read_files_section(config_t *cfgp, int *n_mappings, int *new_keynames, int *new_hashes);
STATICFNDEF int read_database_section(config_t *cfgp, int *n_mappings, int *new_keynames, int *new_hashes);
STATICFNDEF void gtm_keystore_cleanup_node(gtm_keystore_t *);
void gtm_keystore_cleanup_all(void);
STATICFNDEF void gtm_keystore_cleanup_hash_tree(gtm_keystore_hash_link_t *entry);
STATICFNDEF void gtm_keystore_cleanup_keyname_tree(gtm_keystore_keyname_link_t *entry);
STATICFNDEF void gtm_keystore_cleanup_unres_keyname_list(gtm_keystore_unres_keyname_link_t *entry);
int gtmcrypt_getkey_by_keyname(char *keyname, int length, gtm_keystore_t **entry,
int database, int nulled);
int gtmcrypt_getkey_by_hash(unsigned char *hash, gtm_keystore_t **entry);
STATICFNDEF gtm_keystore_t *keystore_lookup_by_hash(unsigned char *hash);
STATICFNDEF gtm_keystore_t *keystore_lookup_by_keyname(char *keyname, int length, int nulled);
STATICFNDEF gtm_keystore_t *keystore_lookup_by_unres_keyname(char *keyname, int *error);
STATICFNDEF gtm_keystore_t *keystore_lookup_by_unres_keyname_hash(unsigned char *hash);
int keystore_new_cipher_ctx(gtm_keystore_t *entry, char *iv, int length, int action);
void keystore_remove_cipher_ctx(gtm_cipher_ctx_t *ctx);
/* Allocate a gtm_keystore_t element. */
#define GC_ALLOCATE_KEYSTORE_ENTRY(X) \
{ \
X = MALLOC(SIZEOF(gtm_keystore_t)); \
(X)->cipher_head = NULL; \
(X)->db_cipher_entry = NULL; \
}
/* Allocate a gtm_keystore_xxx_link_t element. */
#define GC_ALLOCATE_KEYSTORE_LINK(X, TYPE) \
{ \
X = (TYPE *)MALLOC(SIZEOF(TYPE)); \
(X)->left = (X)->right = NULL; \
}
/* Insert a new gtm_keystore_xxx_link_t element in a respective tree. It assumes
* (and asserts) that there is no existing matching node.
*/
#define INSERT_KEY_LINK(ROOT, LINK, TYPE, FIELD, VALUE, LENGTH, FILL_LEN) \
{ \
int diff; \
TYPE *cur_node, **target_node; \
\
target_node = &ROOT; \
while (cur_node = *target_node) /* NOTE: Assignment!!! */ \
{ \
diff = memcmp(cur_node->FIELD, VALUE, LENGTH); \
assert(0 != diff); \
if (diff < 0) \
target_node = &cur_node->left; \
else \
target_node = &cur_node->right; \
} \
GC_ALLOCATE_KEYSTORE_LINK(*target_node, TYPE); \
(*target_node)->link = LINK; \
memset((*target_node)->FIELD, 0, FILL_LEN); \
memcpy((*target_node)->FIELD, VALUE, LENGTH); \
}
/* Find a particular key based on a binary tree with a specific search criterion, such
* as the key's name or hash. The macro causes the caller to return the found node.
*/
#define LOOKUP_KEY(ROOT, TYPE, FIELD, VALUE, LENGTH, CHECK_NULL) \
{ \
int diff; \
TYPE *cur_node; \
\
cur_node = ROOT; \
while (cur_node) \
{ \
diff = memcmp(cur_node->FIELD, VALUE, LENGTH); \
if (0 < diff) \
cur_node = cur_node->right; \
else if ((0 == diff) && \
(CHECK_NULL \
? '\0' == *(((char *)cur_node->FIELD) + LENGTH) \
: TRUE)) \
return cur_node->link; \
else \
cur_node = cur_node->left; \
} \
return NULL; \
}
/* Insert a new gtm_keystore_unres_keyname_link_t element in the unresolved keys list. */
#define INSERT_UNRESOLVED_KEY_LINK(KEY, HASH, KEYNAME) \
{ \
gtm_keystore_unres_keyname_link_t *node; \
\
node = (gtm_keystore_unres_keyname_link_t *)MALLOC( \
SIZEOF(gtm_keystore_unres_keyname_link_t)); \
memcpy(node->key, KEY, SYMMETRIC_KEY_MAX); \
memcpy(node->key_hash, HASH, GTMCRYPT_HASH_LEN); \
memset(node->key_name, 0, GTM_PATH_MAX); \
strncpy(node->key_name, KEYNAME, GTM_PATH_MAX); \
node->next = keystore_by_unres_keyname_head; \
keystore_by_unres_keyname_head = node; \
}
/* Remove all elements from the unresolved keys tree. */
#define REMOVE_UNRESOLVED_KEY_LINKS \
{ \
gtm_keystore_unres_keyname_link_t *curr, *temp; \
\
curr = keystore_by_unres_keyname_head; \
while (curr) \
{ \
temp = curr->next; \
FREE(curr); \
curr = temp; \
} \
keystore_by_unres_keyname_head = NULL; \
}
#endif /* GTMCRYPT_DBK_REF_H */
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