--- /dev/null
+/* -*-c-*-
+ *
+ * The GCM authenticated encryption mode
+ *
+ * (c) 2018 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb. If not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+ * USA.
+ */
+
+#ifndef CATACOMB_GCM_DEF_H
+#define CATACOMB_GCM_DEF_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <string.h>
+
+#include <mLib/bits.h>
+#include <mLib/sub.h>
+
+#ifndef CATACOMB_ARENA_H
+# include "arena.h"
+#endif
+
+#ifndef CATACOMB_BLKC_H
+# include "blkc.h"
+#endif
+
+#ifndef CATACOMB_CT_H
+# include "ct.h"
+#endif
+
+#ifndef CATACOMB_KEYSZ_H
+# include "keysz.h"
+#endif
+
+#ifndef CATACOMB_PARANOIA_H
+# include "paranoia.h"
+#endif
+
+#ifndef CATACOMB_RSVR_H
+# include "rsvr.h"
+#endif
+
+/*----- Type definitions --------------------------------------------------*/
+
+typedef struct gcm_params {
+ unsigned f; /* flags */
+#define GCMF_SWAP 1u /* swap byte order? */
+ unsigned n; /* number of words in block */
+ uint32 poly; /* selected polynomial mask */
+} gcm_params;
+
+/*----- Utilities ---------------------------------------------------------*/
+
+/* Supported block sizes. */
+#define GCM_WIDTHS(_) _(64) _(96) _(128) _(192) _(256)
+#define GCM_NMAX 8
+
+/* Polynomial tails for the supported block sizes. */
+#define GCM_POLY_64 0xd8000000
+#define GCM_POLY_96 0x82600000
+#define GCM_POLY_128 0xe1000000
+#define GCM_POLY_192 0xe1000000
+#define GCM_POLY_256 0xa4200000
+
+/* Determine whether to set the @GCMF_SWAP@ flag. */
+#define GCM_SWAP_L GCMF_SWAP
+#define GCM_SWAP_B 0
+
+/* --- @gcm_mktable@ --- *
+ *
+ * Arguments: @const gcm_params *p@ = pointer to the parameters
+ * @uint32 *ktab@ = where to write the table; there must be
+ * space for %$32 n$% $%n$%-word entries, i.e.,
+ * %$32 n^2$% 32-bit words in total, where %$n$% is
+ * @p->n@, the block size in words
+ * @const uint32 *k@ = input field element
+ *
+ * Returns: ---
+ *
+ * Use: Construct a table for use by @gcm_mulk_...@ below, to
+ * multiply (vaguely) efficiently by @k@.
+ */
+
+extern void gcm_mktable(const gcm_params */*p*/,
+ uint32 */*ktab*/, const uint32 */*k*/);
+
+/* --- @gcm_mulk_N@ --- *
+ *
+ * Arguments: @uint32 *a@ = accumulator to multiply
+ * @const uint32 *ktab@ = table constructed by @gcm_mktable@
+ *
+ * Returns: ---
+ *
+ * Use: Multiply @a@ by @k@ (implicitly represented in @ktab@),
+ * updating @a@ in-place. There are separate functions for each
+ * supported block size because this is the function whose
+ * performance actually matters.
+ */
+
+#define GCM_DECL_MULK(nbits) \
+ extern void gcm_mulk_##nbits(uint32 */*a*/, const uint32 */*ktab*/);
+GCM_WIDTHS(GCM_DECL_MULK)
+#undef GCM_DECL_MULK
+
+/* Dispatch to the appropriate variant of @gcm_mulk@. */
+#define GCM_MULK(PRE, a, ktab) BLKC_GLUE(gcm_mulk_, BLKC_BITS(PRE))(a, ktab)
+
+/* --- @gcm_ghashdone@ --- *
+ *
+ * Arguments: @const gcm_params *p@ = pointer to the parameters
+ * @uint32 *a@ = GHASH accumulator
+ * @const uint32 *ktab@ = multiplication table, built by
+ * @gcm_mktable@
+ * @unsigned long xblocks, yblocks@ = number of whole blocks in
+ * the two inputs
+ * @unsigned xbytes, ybytes@ = number of trailing bytes in the
+ * two inputs
+ *
+ * Returns: ---
+ *
+ * Use: Finishes a GHASH operation by appending the appropriately
+ * encoded lengths of the two constituent messages.
+ */
+
+extern void gcm_ghashdone(const gcm_params */*p*/,
+ uint32 */*a*/, const uint32 */*ktab*/,
+ unsigned long /*xblocks*/, unsigned /*xbytes*/,
+ unsigned long /*yblocks*/, unsigned /*ybytes*/);
+
+/* --- @gcm_concat@ --- *
+ *
+ * Arguments: @const gcm_params *p@ = pointer to the parameters
+ * @uint32 *z@ = GHASH accumulator for suffix, updated
+ * @const uint32 *x@ = GHASH accumulator for prefix
+ * @const uint32 *ktab@ = multiplication table, built by
+ * @gcm_mktable@
+ * @unsigned long n@ = length of suffix in whole blocks
+ *
+ * Returns: ---
+ *
+ * Use: On entry, @x@ and @z@ are the results of hashing two strings
+ * %$a$% and %$b$%, each a whole number of blocks long; in
+ * particular, %$b$% is @n@ blocks long. On exit, @z@ is
+ * updated to be the hash of %$a \cat b$%.
+ */
+
+extern void gcm_concat(const gcm_params */*p*/,
+ uint32 */*z*/, const uint32 */*x*/,
+ const uint32 */*ktab*/, unsigned long /*n*/);
+
+/* Step the counter using GCM's strange only-the-last-32-bits convention. */
+#define GCM_STEP(PRE, w) BLKC_GLUE(GCM_STEP_, BLKC_ENDIAN(PRE))(PRE, w)
+#define GCM_STEP_B(PRE, w) GCM_STEP_X(PRE, BLKC_ID, w)
+#define GCM_STEP_L(PRE, w) GCM_STEP_X(PRE, ENDSWAP32, w)
+#define GCM_STEP_X(PRE, op, w) do { \
+ BLKC_W(w); \
+ _w[PRE##_BLKSZ/4 - 1] = op(op(_w[PRE##_BLKSZ/4 - 1]) + 1); \
+} while (0)
+
+/*----- Macros ------------------------------------------------------------*/
+
+/* --- @GCM_DEF@ --- *
+ *
+ * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
+ *
+ * Use: Creates an implementation for the GCM authenticated-
+ * encryption mode.
+ */
+
+#define GCM_DEF(PRE, pre) GCM_DEFX(PRE, pre, #pre, #pre)
+
+#define GCM_DEFX(PRE, pre, name, fname) \
+ \
+static const gcm_params pre##_gcmparams = { \
+ BLKC_GLUE(GCM_SWAP_, BLKC_ENDIAN(PRE)), \
+ PRE##_BLKSZ/4, \
+ BLKC_GLUE(GCM_POLY_, BLKC_BITS(PRE)) \
+}; \
+ \
+const octet \
+ pre##_gcmnoncesz[] = { KSZ_ANY, PRE##_BLKSZ - 4 }, \
+ pre##_gcmtagsz[] = { KSZ_RANGE, PRE##_BLKSZ, 0, PRE##_BLKSZ, 1 }; \
+ \
+static const rsvr_policy pre##_gcmpolicy = { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
+ \
+/* --- @pre_gcmsetkey@ --- * \
+ * \
+ * Arguments: @pre_gcmkey *key@ = pointer to key block to fill in \
+ * @const void *k@ = pointer to key material \
+ * @size_t ksz@ = size of key material \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Initializes an GCM key block. \
+ */ \
+ \
+void pre##_gcmsetkey(pre##_gcmkey *key, const void *k, size_t ksz) \
+{ \
+ uint32 t[PRE##_BLKSZ/4]; \
+ \
+ /* Initialize the block cipher. */ \
+ pre##_init(&key->ctx, k, ksz); \
+ \
+ /* Set up the GHASH multiplication table. */ \
+ BLKC_ZERO(PRE, t); pre##_eblk(&key->ctx, t, t); \
+ gcm_mktable(&pre##_gcmparams, key->ktab, t); \
+} \
+ \
+/* --- @pre_gcmaadinit@ --- * \
+ * \
+ * Arguments: @pre_gcmaadctx *aad@ = pointer to AAD context \
+ * @const pre_gcmkey *key@ = pointer to key block \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Initializes an GCM AAD (`additional authenticated \
+ * data') context associated with a given key. AAD \
+ * contexts can be copied and/or reused, saving time if \
+ * the AAD for a number of messages has a common prefix. \
+ * \
+ * The @key@ doesn't need to be kept around, though \
+ * usually there'll at least be another copy in some GCM \
+ * operation context because the AAD on its own isn't much \
+ * good. \
+ */ \
+ \
+void pre##_gcmaadinit(pre##_gcmaadctx *aad, const pre##_gcmkey *key) \
+ { aad->k = *key; aad->off = 0; aad->len = 0; BLKC_ZERO(PRE, aad->a); } \
+ \
+/* --- @pre_gcmaadhash@ --- * \
+ * \
+ * Arguments: @pre_gcmaadctx *aad@ = pointer to AAD context \
+ * @const void *p@ = pointer to AAD material \
+ * @size_t sz@ = length of AAD material \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Feeds AAD into the context. \
+ */ \
+ \
+void pre##_gcmaadhash(pre##_gcmaadctx *aad, const void *p, size_t sz) \
+{ \
+ rsvr_state st; \
+ const octet *q; \
+ \
+ rsvr_setup(&st, &pre##_gcmpolicy, aad->b, &aad->off, p, sz); \
+ RSVR_DO(&st) while ((q = RSVR_NEXT(&st, PRE##_BLKSZ)) != 0) { \
+ BLKC_XLOAD(PRE, aad->a, q); GCM_MULK(PRE, aad->a, aad->k.ktab); \
+ aad->len++; \
+ } \
+} \
+ \
+/* --- @pre_gcminit@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to GCM context \
+ * @const pre_gcmkey *key@ = pointer to key block \
+ * @const void *n@ = pointer to nonce \
+ * @size_t nsz@ = size of nonce \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Initialize an GCM operation context with a given key. \
+ * \
+ * The original key needn't be kept around any more. \
+ */ \
+ \
+void pre##_gcminit(pre##_gcmctx *ctx, const pre##_gcmkey *k, \
+ const void *n, size_t nsz) \
+ { ctx->k = *k; pre##_gcmreinit(ctx, n, nsz); } \
+ \
+/* --- @pre_gcmreinit@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to GCM context \
+ * @const void *n@ = pointer to nonce \
+ * @size_t nsz@ = size of nonce \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Reinitialize an GCM operation context, changing the \
+ * nonce. \
+ */ \
+ \
+void pre##_gcmreinit(pre##_gcmctx *ctx, const void *n, size_t nsz) \
+{ \
+ octet b[PRE##_BLKSZ]; \
+ const octet *q = n; \
+ size_t nblocks; \
+ unsigned i; \
+ \
+ /* Zero the counters. */ \
+ ctx->off = 0; ctx->len = 0; \
+ BLKC_ZERO(PRE, ctx->a); \
+ \
+ /* Calculate the initial counter from the nonce. */ \
+ if (nsz == PRE##_BLKSZ - 4) { \
+ /* Easy version: initialize the final word to 1 and copy the \
+ * remaining words from the nonce. (The spec shows the nonce and \
+ * counter the other way around for 64-bit block ciphers, but I'm \
+ * sure this is just a mistake.) \
+ */ \
+ \
+ for (i = 0; i < PRE##_BLKSZ/4 - 1; i++) \
+ { ctx->c0[i] = BLKC_LOAD_E(PRE)(q); q += 4; } \
+ ctx->c0[PRE##_BLKSZ/4 - 1] = BLKC_BWORD(PRE, 1); \
+ } else { \
+ /* Harder version: hash the nonce down with GHASH. */ \
+ \
+ BLKC_ZERO(PRE, ctx->c0); nblocks = 0; \
+ while (nsz >= PRE##_BLKSZ) { \
+ BLKC_XLOAD(PRE, ctx->c0, q); q += PRE##_BLKSZ; \
+ GCM_MULK(PRE, ctx->c0, ctx->k.ktab); \
+ nsz -= PRE##_BLKSZ; nblocks++; \
+ } \
+ if (nsz) { \
+ memcpy(b, q, nsz); memset(b + nsz, 0, PRE##_BLKSZ - nsz); \
+ BLKC_XLOAD(PRE, ctx->c0, b); \
+ GCM_MULK(PRE, ctx->c0, ctx->k.ktab); \
+ } \
+ gcm_ghashdone(&pre##_gcmparams, ctx->c0, ctx->k.ktab, \
+ 0, 0, nblocks, nsz); \
+ } \
+ \
+ /* We must remember the initial counter for the final tag \
+ * calculation. (I conjecture that storing the final counter instead \
+ * would be just as secure, and require less state, but I've not \
+ * proven this, and anyway it wouldn't interoperate.) Copy it to \
+ * make the working counter. \
+ */ \
+ BLKC_MOVE(PRE, ctx->c, ctx->c0); \
+} \
+ \
+/* --- @pre_gcmencrypt@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to GCM operation context \
+ * @const void *src@ = pointer to plaintext message chunk \
+ * @size_t sz@ = size of the plaintext \
+ * @buf *dst@ = a buffer to write the ciphertext to \
+ * \
+ * Returns: Zero on success; @-1@ on failure. \
+ * \
+ * Use: Encrypts a chunk of a plaintext message, writing a \
+ * chunk of ciphertext to the output buffer and updating \
+ * the operation state. \
+ * \
+ * For GCM, we always write a ciphertext chunk the same \
+ * size as the plaintext. The messing about with @buf@ \
+ * objects makes the interface consistent with other AEAD \
+ * schemes which can't do this. \
+ */ \
+ \
+int pre##_gcmencrypt(pre##_gcmctx *ctx, \
+ const void *src, size_t sz, buf *dst) \
+{ \
+ rsvr_plan plan; \
+ uint32 t[PRE##_BLKSZ/4]; \
+ const octet *p = src; \
+ octet *q, *r, y; \
+ \
+ /* Allocate space for the ciphertext. */ \
+ if (sz) { q = buf_get(dst, sz); if (!q) return (-1); } \
+ else q = 0; \
+ \
+ /* Determine the buffering plan. Our buffer is going to do double- \
+ * duty here. The end portion is going to contain mask from the \
+ * encrypted counter which we mix into the plaintext to encrypt it; \
+ * the start portion, which originally mask bytes we've already used, \
+ * will hold the output ciphertext, which will eventually be \
+ * collected into the GHASH state. \
+ */ \
+ rsvr_mkplan(&plan, &pre##_gcmpolicy, ctx->off, sz); \
+ \
+ /* Initial portion, fulfilled from the buffer. If the buffer is \
+ * empty, then that means that we haven't yet encrypted the current \
+ * counter, so we should do that and advance it. \
+ */ \
+ if (plan.head) { \
+ if (!ctx->off) { \
+ GCM_STEP(PRE, ctx->c); pre##_eblk(&ctx->k.ctx, ctx->c, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ } \
+ r = ctx->b + ctx->off; ctx->off += plan.head; \
+ while (plan.head--) { y = *p++ ^ *r; *r++ = *q++ = y; } \
+ } \
+ \
+ /* If we've filled up the buffer then we need to cycle the MAC and \
+ * reset the offset. \
+ */ \
+ if (plan.from_rsvr) { \
+ BLKC_XLOAD(PRE, ctx->a, ctx->b); GCM_MULK(PRE, ctx->a, ctx->k.ktab); \
+ ctx->len++; ctx->off = 0; \
+ } \
+ \
+ /* Now to process the main body of the input. */ \
+ while (plan.from_input) { \
+ GCM_STEP(PRE, ctx->c); pre##_eblk(&ctx->k.ctx, ctx->c, t); \
+ BLKC_XLOAD(PRE, t, p); p += PRE##_BLKSZ; \
+ BLKC_STORE(PRE, q, t); q += PRE##_BLKSZ; \
+ BLKC_XMOVE(PRE, ctx->a, t); GCM_MULK(PRE, ctx->a, ctx->k.ktab); \
+ plan.from_input -= PRE##_BLKSZ; ctx->len++; \
+ } \
+ \
+ /* Finally, deal with any final portion. If there is one, we know \
+ * that the buffer is empty: we must have filled it above, or this \
+ * would all count as `initial' data. \
+ */ \
+ if (plan.tail) { \
+ GCM_STEP(PRE, ctx->c); pre##_eblk(&ctx->k.ctx, ctx->c, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ r = ctx->b; ctx->off += plan.tail; \
+ while (plan.tail--) { y = *p++ ^ *r; *r++ = *q++ = y; } \
+ } \
+ \
+ /* And we're done. */ \
+ return (0); \
+} \
+ \
+/* --- @pre_gcmdecrypt@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to GCM operation context \
+ * @const void *src@ = pointer to ciphertext message chunk \
+ * @size_t sz@ = size of the ciphertext \
+ * @buf *dst@ = a buffer to write the plaintext to \
+ * \
+ * Returns: Zero on success; @-1@ on failure. \
+ * \
+ * Use: Decrypts a chunk of a ciphertext message, writing a \
+ * chunk of plaintext to the output buffer and updating \
+ * the operation state. \
+ * \
+ * For GCM, we always write a plaintext chunk the same \
+ * size as the ciphertext. The messing about with @buf@ \
+ * objects makes the interface consistent with other AEAD \
+ * schemes which can't do this. \
+ */ \
+ \
+int pre##_gcmdecrypt(pre##_gcmctx *ctx, \
+ const void *src, size_t sz, buf *dst) \
+{ \
+ rsvr_plan plan; \
+ uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ]; \
+ const octet *p = src; \
+ octet *q, *r, y; \
+ \
+ /* Allocate space for the plaintext. */ \
+ if (sz) { q = buf_get(dst, sz); if (!q) return (-1); } \
+ else q = 0; \
+ \
+ /* Determine the buffering plan. Our buffer is going to do double- \
+ * duty here. The end portion is going to contain mask from the \
+ * encrypted counter which we mix into the plaintext to encrypt it; \
+ * the start portion, which originally mask bytes we've already used, \
+ * will hold the input ciphertext, which will eventually be \
+ * collected into the GHASH state. \
+ */ \
+ rsvr_mkplan(&plan, &pre##_gcmpolicy, ctx->off, sz); \
+ \
+ /* Initial portion, fulfilled from the buffer. If the buffer is \
+ * empty, then that means that we haven't yet encrypted the current \
+ * counter, so we should do that and advance it. \
+ */ \
+ if (plan.head) { \
+ if (!ctx->off) { \
+ GCM_STEP(PRE, ctx->c); pre##_eblk(&ctx->k.ctx, ctx->c, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ } \
+ r = ctx->b + ctx->off; ctx->off += plan.head; \
+ while (plan.head--) { y = *p++; *q++ = y ^ *r; *r++ = y; } \
+ } \
+ \
+ /* If we've filled up the buffer then we need to cycle the MAC and \
+ * reset the offset. \
+ */ \
+ if (plan.from_rsvr) { \
+ BLKC_XLOAD(PRE, ctx->a, ctx->b); GCM_MULK(PRE, ctx->a, ctx->k.ktab); \
+ ctx->len++; ctx->off = 0; \
+ } \
+ \
+ /* Now to process the main body of the input. */ \
+ while (plan.from_input) { \
+ GCM_STEP(PRE, ctx->c); pre##_eblk(&ctx->k.ctx, ctx->c, t); \
+ BLKC_LOAD(PRE, u, p); p += PRE##_BLKSZ; \
+ BLKC_XSTORE(PRE, q, t, u); q += PRE##_BLKSZ; \
+ BLKC_XMOVE(PRE, ctx->a, u); GCM_MULK(PRE, ctx->a, ctx->k.ktab); \
+ plan.from_input -= PRE##_BLKSZ; ctx->len++; \
+ } \
+ \
+ /* Finally, deal with any final portion. If there is one, we know \
+ * that the buffer is empty: we must have filled it above, or this \
+ * would all count as `initial' data. \
+ */ \
+ if (plan.tail) { \
+ GCM_STEP(PRE, ctx->c); pre##_eblk(&ctx->k.ctx, ctx->c, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ r = ctx->b; ctx->off += plan.tail; \
+ while (plan.tail--) { y = *p++; *q++ = y ^ *r; *r++ = y; } \
+ } \
+ \
+ /* And we're done. */ \
+ return (0); \
+} \
+ \
+/* --- @pre_gcmtag@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to an GCM context \
+ * @const pre_gcmaadctx *aad@ = pointer to AAD context, or \
+ * null \
+ * @octet *t@ = where to write a (full-length) tag \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Finishes an GCM operation, by calculating the tag. \
+ */ \
+ \
+static void pre##_gcmtag(pre##_gcmctx *ctx, \
+ const pre##_gcmaadctx *aad, octet *t) \
+{ \
+ octet b[PRE##_BLKSZ]; \
+ uint32 u[PRE##_BLKSZ/4]; \
+ unsigned long n; \
+ \
+ /* Finish tagging the ciphertext. */ \
+ if (ctx->off) { \
+ memcpy(b, ctx->b, ctx->off); \
+ memset(b + ctx->off, 0, PRE##_BLKSZ - ctx->off); \
+ BLKC_XLOAD(PRE, ctx->a, b); GCM_MULK(PRE, ctx->a, ctx->k.ktab); \
+ } \
+ \
+ /* If there's no AAD, because the pointer is null or no data was \
+ * supplied, then apply that to the GHASH state. (Otherwise there's \
+ * nothing to do here.) \
+ */ \
+ if (aad && (aad->len || aad->off)) { \
+ BLKC_MOVE(PRE, u, aad->a); \
+ if (aad->off) { \
+ memcpy(b, aad->b, aad->off); \
+ memset(b + aad->off, 0, PRE##_BLKSZ - aad->off); \
+ BLKC_XLOAD(PRE, u, b); GCM_MULK(PRE, u, ctx->k.ktab); \
+ } \
+ n = ctx->len; if (ctx->off) n++; \
+ gcm_concat(&pre##_gcmparams, ctx->a, u, ctx->k.ktab, n); \
+ } \
+ \
+ /* Finish off the hash by appending the length. */ \
+ gcm_ghashdone(&pre##_gcmparams, ctx->a, ctx->k.ktab, \
+ aad ? aad->len : 0, aad ? aad->off : 0, \
+ ctx->len, ctx->off); \
+ \
+ /* Mask the hash and store. */ \
+ pre##_eblk(&ctx->k.ctx, ctx->c0, u); \
+ BLKC_XSTORE(PRE, t, ctx->a, u); \
+} \
+ \
+/* --- @pre_gcmencryptdone@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to an GCM context \
+ * @const pre_gcmaadctx *aad@ = pointer to AAD context, or \
+ * null \
+ * @buf *dst@ = buffer for remaining ciphertext \
+ * @void *tag@ = where to write the tag \
+ * @size_t tsz@ = length of tag to store \
+ * \
+ * Returns: Zero on success; @-1@ on failure. \
+ * \
+ * Use: Completes an GCM encryption operation. The @aad@ \
+ * pointer may be null if there is no additional \
+ * authenticated data. GCM doesn't buffer ciphertext, but \
+ * the output buffer is provided anyway for consistency \
+ * with other AEAD schemes which don't have this property; \
+ * the function will fail if the output buffer is broken. \
+ */ \
+ \
+int pre##_gcmencryptdone(pre##_gcmctx *ctx, \
+ const pre##_gcmaadctx *aad, buf *dst, \
+ void *tag, size_t tsz) \
+{ \
+ octet t[PRE##_BLKSZ]; \
+ \
+ if (tsz > PRE##_BLKSZ) return (-1); \
+ if (!BOK(dst)) return (-1); \
+ pre##_gcmtag(ctx, aad, t); memcpy(tag, t, tsz); \
+ return (0); \
+} \
+ \
+/* --- @pre_gcmdecryptdone@ --- * \
+ * \
+ * Arguments: @pre_gcmctx *ctx@ = pointer to an GCM context \
+ * @const pre_gcmaadctx *aad@ = pointer to AAD context, or \
+ * null \
+ * @buf *dst@ = buffer for remaining plaintext \
+ * @const void *tag@ = tag to verify \
+ * @size_t tsz@ = length of tag \
+ * \
+ * Returns: @+1@ for complete success; @0@ if tag verification \
+ * failed; @-1@ for other kinds of errors. \
+ * \
+ * Use: Completes an GCM decryption operation. The @aad@ \
+ * pointer may be null if there is no additional \
+ * authenticated data. GCM doesn't buffer plaintext, but \
+ * the output buffer is provided anyway for consistency \
+ * with other AEAD schemes which don't have this property; \
+ * the function will fail if the output buffer is broken. \
+ */ \
+ \
+int pre##_gcmdecryptdone(pre##_gcmctx *ctx, \
+ const pre##_gcmaadctx *aad, buf *dst, \
+ const void *tag, size_t tsz) \
+{ \
+ octet t[PRE##_BLKSZ]; \
+ \
+ if (tsz > PRE##_BLKSZ) return (-1); \
+ if (!BOK(dst)) return (-1); \
+ pre##_gcmtag(ctx, aad, t); \
+ if (!ct_memeq(tag, t, tsz)) return (0); \
+ else return (+1); \
+} \
+ \
+/* --- Generic AEAD interface --- */ \
+ \
+typedef struct gactx { \
+ gaead_aad a; \
+ pre##_gcmaadctx aad; \
+} gactx; \
+ \
+static gaead_aad *gadup(const gaead_aad *a) \
+ { gactx *aad = S_CREATE(gactx); *aad = *(gactx *)a; return (&aad->a); } \
+ \
+static void gahash(gaead_aad *a, const void *h, size_t hsz) \
+ { gactx *aad = (gactx *)a; pre##_gcmaadhash(&aad->aad, h, hsz); } \
+ \
+static void gadestroy(gaead_aad *a) \
+ { gactx *aad = (gactx *)a; BURN(*aad); S_DESTROY(aad); } \
+ \
+static const gaead_aadops gaops = \
+ { &pre##_gcm, gadup, gahash, gadestroy }; \
+ \
+static gaead_aad *gaad(const pre##_gcmkey *k) \
+{ \
+ gactx *aad = S_CREATE(gactx); \
+ aad->a.ops = &gaops; \
+ pre##_gcmaadinit(&aad->aad, k); \
+ return (&aad->a); \
+} \
+ \
+typedef struct gectx { \
+ gaead_enc e; \
+ pre##_gcmctx ctx; \
+} gectx; \
+ \
+static gaead_aad *geaad(gaead_enc *e) \
+ { gectx *enc = (gectx *)e; return (gaad(&enc->ctx.k)); } \
+ \
+static int gereinit(gaead_enc *e, const void *n, size_t nsz, \
+ size_t hsz, size_t msz, size_t tsz) \
+{ \
+ gectx *enc = (gectx *)e; \
+ \
+ if (tsz > PRE##_BLKSZ) return (-1); \
+ pre##_gcmreinit(&enc->ctx, n, nsz); \
+ return (0); \
+} \
+ \
+static int geenc(gaead_enc *e, const void *m, size_t msz, buf *b) \
+{ \
+ gectx *enc = (gectx *)e; \
+ return (pre##_gcmencrypt(&enc->ctx, m, msz, b)); \
+} \
+ \
+static int gedone(gaead_enc *e, const gaead_aad *a, \
+ buf *b, void *t, size_t tsz) \
+{ \
+ gectx *enc = (gectx *)e; gactx *aad = (gactx *)a; \
+ assert(!a || a->ops == &gaops); \
+ return (pre##_gcmencryptdone(&enc->ctx, a ? &aad->aad : 0, b, t, tsz)); \
+} \
+ \
+static void gedestroy(gaead_enc *e) \
+ { gectx *enc = (gectx *)e; BURN(*enc); S_DESTROY(enc); } \
+ \
+static const gaead_encops geops = \
+ { &pre##_gcm, geaad, gereinit, geenc, gedone, gedestroy }; \
+ \
+typedef struct gdctx { \
+ gaead_dec d; \
+ pre##_gcmctx ctx; \
+} gdctx; \
+ \
+static gaead_aad *gdaad(gaead_dec *d) \
+ { gdctx *dec = (gdctx *)d; return (gaad(&dec->ctx.k)); } \
+ \
+static int gdreinit(gaead_dec *d, const void *n, size_t nsz, \
+ size_t hsz, size_t csz, size_t tsz) \
+{ \
+ gdctx *dec = (gdctx *)d; \
+ \
+ if (tsz > PRE##_BLKSZ) return (-1); \
+ pre##_gcmreinit(&dec->ctx, n, nsz); \
+ return (0); \
+} \
+ \
+static int gddec(gaead_dec *d, const void *c, size_t csz, buf *b) \
+{ \
+ gdctx *dec = (gdctx *)d; \
+ return (pre##_gcmdecrypt(&dec->ctx, c, csz, b)); \
+} \
+ \
+static int gddone(gaead_dec *d, const gaead_aad *a, \
+ buf *b, const void *t, size_t tsz) \
+{ \
+ gdctx *dec = (gdctx *)d; gactx *aad = (gactx *)a; \
+ assert(!a || a->ops == &gaops); \
+ return (pre##_gcmdecryptdone(&dec->ctx, a ? &aad->aad : 0, b, t, tsz)); \
+} \
+ \
+static void gddestroy(gaead_dec *d) \
+ { gdctx *dec = (gdctx *)d; BURN(*dec); S_DESTROY(dec); } \
+ \
+static const gaead_decops gdops = \
+ { &pre##_gcm, gdaad, gdreinit, gddec, gddone, gddestroy }; \
+ \
+typedef struct gkctx { \
+ gaead_key k; \
+ pre##_gcmkey key; \
+} gkctx; \
+ \
+static gaead_aad *gkaad(const gaead_key *k) \
+ { gkctx *key = (gkctx *)k; return (gaad(&key->key)); } \
+ \
+static gaead_enc *gkenc(const gaead_key *k, const void *n, size_t nsz, \
+ size_t hsz, size_t msz, size_t tsz) \
+{ \
+ gkctx *key = (gkctx *)k; \
+ gectx *enc = S_CREATE(gectx); \
+ \
+ enc->e.ops = &geops; \
+ pre##_gcminit(&enc->ctx, &key->key, n, nsz); \
+ return (&enc->e); \
+} \
+ \
+static gaead_dec *gkdec(const gaead_key *k, const void *n, size_t nsz, \
+ size_t hsz, size_t csz, size_t tsz) \
+{ \
+ gkctx *key = (gkctx *)k; \
+ gdctx *dec = S_CREATE(gdctx); \
+ \
+ dec->d.ops = &gdops; \
+ pre##_gcminit(&dec->ctx, &key->key, n, nsz); \
+ return (&dec->d); \
+} \
+ \
+static void gkdestroy(gaead_key *k) \
+ { gkctx *key = (gkctx *)k; BURN(*key); S_DESTROY(key); } \
+ \
+static const gaead_keyops gkops = \
+ { &pre##_gcm, gkaad, gkenc, gkdec, gkdestroy }; \
+ \
+static gaead_key *gckey(const void *k, size_t ksz) \
+{ \
+ gkctx *key = S_CREATE(gkctx); \
+ key->k.ops = &gkops; \
+ pre##_gcmsetkey(&key->key, k, ksz); \
+ return (&key->k); \
+} \
+ \
+const gcaead pre##_gcm = { \
+ name "-gcm", \
+ pre##_keysz, pre##_gcmnoncesz, pre##_gcmtagsz, \
+ PRE##_BLKSZ, 0, 0, 0, \
+ gckey \
+}; \
+ \
+GCM_TESTX(PRE, pre, name, fname)
+
+/*----- Test rig ----------------------------------------------------------*/
+
+#define GCM_TEST(PRE, pre) GCM_TESTX(PRE, pre, #pre, #pre)
+
+/* --- @GCM_TEST@ --- *
+ *
+ * Arguments: @PRE, pre@ = prefixes for the underlying block cipher
+ *
+ * Use: Standard test rig for GCM functions.
+ */
+
+#ifdef TEST_RIG
+
+#include <stdio.h>
+
+#include <mLib/dstr.h>
+#include <mLib/quis.h>
+#include <mLib/testrig.h>
+
+#define GCM_TESTX(PRE, pre, name, fname) \
+ \
+static int gcmverify(dstr *v) \
+{ \
+ pre##_gcmkey key; \
+ pre##_gcmaadctx aad; \
+ pre##_gcmctx ctx; \
+ int ok = 1, win; \
+ int i; \
+ octet *p; \
+ int szs[] = { 1, 7, 192, -1, 0 }, *ip; \
+ size_t hsz, msz; \
+ dstr d = DSTR_INIT, t = DSTR_INIT; \
+ buf b; \
+ \
+ dstr_ensure(&d, v[4].len > v[3].len ? v[4].len : v[3].len); \
+ dstr_ensure(&t, v[5].len); t.len = v[5].len; \
+ \
+ pre##_gcmsetkey(&key, v[0].buf, v[0].len); \
+ \
+ for (ip = szs; *ip; ip++) { \
+ \
+ pre##_gcminit(&ctx, &key, (octet *)v[1].buf, v[1].len); \
+ \
+ i = *ip; \
+ hsz = v[2].len; \
+ if (i == -1) i = hsz; \
+ if (i > hsz) continue; \
+ p = (octet *)v[2].buf; \
+ pre##_gcmaadinit(&aad, &key); \
+ while (hsz) { \
+ if (i > hsz) i = hsz; \
+ pre##_gcmaadhash(&aad, p, i); \
+ p += i; hsz -= i; \
+ } \
+ \
+ buf_init(&b, d.buf, d.sz); \
+ i = *ip; \
+ msz = v[3].len; \
+ if (i == -1) i = msz; \
+ if (i > msz) continue; \
+ p = (octet *)v[3].buf; \
+ while (msz) { \
+ if (i > msz) i = msz; \
+ if (pre##_gcmencrypt(&ctx, p, i, &b)) { \
+ puts("!! gcmencrypt reports failure"); \
+ goto fail_enc; \
+ } \
+ p += i; msz -= i; \
+ } \
+ \
+ if (pre##_gcmencryptdone(&ctx, &aad, &b, (octet *)t.buf, t.len)) { \
+ puts("!! gcmencryptdone reports failure"); \
+ goto fail_enc; \
+ } \
+ d.len = BLEN(&b); \
+ \
+ if (d.len != v[4].len || \
+ memcmp(d.buf, v[4].buf, v[4].len) != 0 || \
+ memcmp(t.buf, v[5].buf, v[5].len) != 0) { \
+ fail_enc: \
+ printf("\nfail encrypt:\n\tstep = %i", *ip); \
+ fputs("\n\tkey = ", stdout); type_hex.dump(&v[0], stdout); \
+ fputs("\n\tnonce = ", stdout); type_hex.dump(&v[1], stdout); \
+ fputs("\n\theader = ", stdout); type_hex.dump(&v[2], stdout); \
+ fputs("\n\tmessage = ", stdout); type_hex.dump(&v[3], stdout); \
+ fputs("\n\texp ct = ", stdout); type_hex.dump(&v[4], stdout); \
+ fputs("\n\tcalc ct = ", stdout); type_hex.dump(&d, stdout); \
+ fputs("\n\texp tag = ", stdout); type_hex.dump(&v[5], stdout); \
+ fputs("\n\tcalc tag = ", stdout); type_hex.dump(&t, stdout); \
+ putchar('\n'); \
+ ok = 0; \
+ } \
+ \
+ pre##_gcminit(&ctx, &key, (octet *)v[1].buf, v[1].len); \
+ \
+ buf_init(&b, d.buf, d.sz); \
+ i = *ip; \
+ msz = v[4].len; \
+ if (i == -1) i = msz; \
+ if (i > msz) continue; \
+ p = (octet *)v[4].buf; \
+ while (msz) { \
+ if (i > msz) i = msz; \
+ if (pre##_gcmdecrypt(&ctx, p, i, &b)) { \
+ puts("!! gcmdecrypt reports failure"); \
+ win = 0; goto fail_dec; \
+ } \
+ p += i; msz -= i; \
+ } \
+ \
+ win = pre##_gcmdecryptdone(&ctx, &aad, &b, \
+ (octet *)v[5].buf, v[5].len); \
+ if (win < 0) { \
+ puts("!! gcmdecryptdone reports failure"); \
+ goto fail_dec; \
+ } \
+ d.len = BLEN(&b); \
+ \
+ if (d.len != v[3].len || !win || \
+ memcmp(d.buf, v[3].buf, v[3].len) != 0) { \
+ fail_dec: \
+ printf("\nfail decrypt:\n\tstep = %i", *ip); \
+ fputs("\n\tkey = ", stdout); type_hex.dump(&v[0], stdout); \
+ fputs("\n\tnonce = ", stdout); type_hex.dump(&v[1], stdout); \
+ fputs("\n\theader = ", stdout); type_hex.dump(&v[2], stdout); \
+ fputs("\n\tciphertext = ", stdout); type_hex.dump(&v[4], stdout); \
+ fputs("\n\texp pt = ", stdout); type_hex.dump(&v[3], stdout); \
+ fputs("\n\tcalc pt = ", stdout); type_hex.dump(&d, stdout); \
+ fputs("\n\ttag = ", stdout); type_hex.dump(&v[5], stdout); \
+ printf("\n\tverify %s", win ? "ok" : "FAILED"); \
+ putchar('\n'); \
+ ok = 0; \
+ } \
+ } \
+ \
+ dstr_destroy(&d); dstr_destroy(&t); \
+ return (ok); \
+} \
+ \
+static test_chunk aeaddefs[] = { \
+ { name "-gcm", gcmverify, \
+ { &type_hex, &type_hex, &type_hex, &type_hex, \
+ &type_hex, &type_hex, 0 } }, \
+ { 0, 0, { 0 } } \
+}; \
+ \
+int main(int argc, char *argv[]) \
+{ \
+ ego(argv[0]); \
+ test_run(argc, argv, aeaddefs, SRCDIR"/t/" fname); \
+ return (0); \
+}
+
+#else
+# define GCM_TESTX(PRE, pre, name, fname)
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
~mdw / catacomb / blobdiff