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This adds a key management system that stores (currently) two data encryption keys of length 128, 192, or 256 bits. The data keys are AES256 encrypted using a key encryption key, and validated via GCM cipher mode. A command to obtain the key encryption key must be specified at initdb time, and will be run at every database server start. New parameters allow a file descriptor open to the terminal to be passed. pg_upgrade support has also been added. Discussion: https://postgr.es/m/CA+fd4k7q5o6Nc_AaX6BcYM9yqTbC6_pnH-6nSD=54Zp6NBQTCQ@mail.gmail.com Discussion: https://postgr.es/m/20201202213814.GG20285@momjian.us Author: Masahiko Sawada, me, Stephen Frost
98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
/*-------------------------------------------------------------------------
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*
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* kmgr_utils.h
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* Declarations for utility function for file encryption key
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*
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* Portions Copyright (c) 2020, PostgreSQL Global Development Group
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*
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* src/include/common/kmgr_utils.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef KMGR_UTILS_H
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#define KMGR_UTILS_H
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#include "common/cipher.h"
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/* Current version number */
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#define KMGR_VERSION 1
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/*
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* Directories where cluster file encryption keys reside within PGDATA.
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*/
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#define KMGR_DIR "pg_cryptokeys"
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#define KMGR_DIR_PID KMGR_DIR"/pg_alterckey.pid"
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#define LIVE_KMGR_DIR KMGR_DIR"/live"
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/* used during cluster key rotation */
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#define NEW_KMGR_DIR KMGR_DIR"/new"
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#define OLD_KMGR_DIR KMGR_DIR"/old"
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/* CryptoKey file name is keys id */
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#define CryptoKeyFilePath(path, dir, id) \
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snprintf((path), MAXPGPATH, "%s/%d", (dir), (id))
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/*
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* Identifiers of internal keys.
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*/
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#define KMGR_KEY_ID_REL 0
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#define KMGR_KEY_ID_WAL 1
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#define KMGR_MAX_INTERNAL_KEYS 2
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/* We always, today, use a 256-bit AES key. */
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#define KMGR_CLUSTER_KEY_LEN PG_AES256_KEY_LEN
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/* double for hex format, plus some for spaces, \r,\n, and null byte */
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#define ALLOC_KMGR_CLUSTER_KEY_LEN (KMGR_CLUSTER_KEY_LEN * 2 + 10 + 2 + 1)
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/* Maximum length of key the key manager can store */
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#define KMGR_MAX_KEY_LEN 256
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#define KMGR_MAX_KEY_LEN_BYTES KMGR_MAX_KEY_LEN / 8
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#define KMGR_MAX_WRAPPED_KEY_LEN KmgrSizeOfCipherText(KMGR_MAX_KEY_LEN)
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/*
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* Cryptographic key data structure.
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*
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* This is the structure we use to write out the encrypted keys.
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*
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* pgkey_id is the identifier for this key (should be same as the
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* file name and be one of KMGR_KEY_ID_* from above). This is what
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* we consider our 'context' or 'fixed' portion of the deterministic
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* IV we create.
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*
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* counter is updated each time we use the cluster KEK to encrypt a
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* new key. This is our the 'invocation' field of the deterministic
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* IV we create.
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*
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* Absolutely essential when using GCM (or CTR) is that the IV is unique,
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* for a given key, but a deterministic IV such as this is perfectly
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* acceptable and encouraged. If (and only if!) the KEK is changed to a
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* new key, then we can re-initialize the counter.
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*
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* Detailed discussion of deterministic IV creation can be found here:
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*
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* https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
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*
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* tag is the GCM tag which is produced and must be validated in order
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* to be able to trust the results of our decryption.
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*
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* encrypted_key is the encrypted key length (as an int) + encrypted key.
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*/
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typedef struct CryptoKey
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{
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uint64 pgkey_id; /* Upper half of IV */
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uint64 counter; /* Lower half of IV */
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uint128 tag; /* GCM tag */
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unsigned char encrypted_key[sizeof(int) + KMGR_MAX_KEY_LEN_BYTES];
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} CryptoKey;
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extern bool kmgr_wrap_key(PgCipherCtx *ctx, CryptoKey *in, CryptoKey *out);
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extern bool kmgr_unwrap_key(PgCipherCtx *ctx, CryptoKey *in, CryptoKey *out);
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extern bool kmgr_verify_cluster_key(unsigned char *cluster_key,
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CryptoKey *in_keys, CryptoKey *out_keys,
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int nkey);
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extern int kmgr_run_cluster_key_command(char *cluster_key_command,
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char *buf, int size, char *dir);
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extern CryptoKey *kmgr_get_cryptokeys(const char *path, int *nkeys);
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#endif /* KMGR_UTILS_H */
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