/*
- * Modified to interface to the Linux kernel
+ * VMAC: Message Authentication Code using Universal Hashing
+ *
+ * Reference: https://tools.ietf.org/html/draft-krovetz-vmac-01
+ *
* Copyright (c) 2009, Intel Corporation.
+ * Copyright (c) 2018, Google Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* Place - Suite 330, Boston, MA 02111-1307 USA.
*/
-/* --------------------------------------------------------------------------
- * VMAC and VHASH Implementation by Ted Krovetz (tdk@acm.org) and Wei Dai.
- * This implementation is herby placed in the public domain.
- * The authors offers no warranty. Use at your own risk.
- * Please send bug reports to the authors.
- * Last modified: 17 APR 08, 1700 PDT
- * ----------------------------------------------------------------------- */
+/*
+ * Derived from:
+ * VMAC and VHASH Implementation by Ted Krovetz (tdk@acm.org) and Wei Dai.
+ * This implementation is herby placed in the public domain.
+ * The authors offers no warranty. Use at your own risk.
+ * Last modified: 17 APR 08, 1700 PDT
+ */
+#include <asm/unaligned.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <asm/byteorder.h>
#include <crypto/scatterwalk.h>
-#include <crypto/vmac.h>
#include <crypto/internal/hash.h>
/*
+ * User definable settings.
+ */
+#define VMAC_TAG_LEN 64
+#define VMAC_KEY_SIZE 128/* Must be 128, 192 or 256 */
+#define VMAC_KEY_LEN (VMAC_KEY_SIZE/8)
+#define VMAC_NHBYTES 128/* Must 2^i for any 3 < i < 13 Standard = 128*/
+
+/* per-transform (per-key) context */
+struct vmac_tfm_ctx {
+ struct crypto_cipher *cipher;
+ u64 nhkey[(VMAC_NHBYTES/8)+2*(VMAC_TAG_LEN/64-1)];
+ u64 polykey[2*VMAC_TAG_LEN/64];
+ u64 l3key[2*VMAC_TAG_LEN/64];
+};
+
+/* per-request context */
+struct vmac_desc_ctx {
+ union {
+ u8 partial[VMAC_NHBYTES]; /* partial block */
+ __le64 partial_words[VMAC_NHBYTES / 8];
+ };
+ unsigned int partial_size; /* size of the partial block */
+ bool first_block_processed;
+ u64 polytmp[2*VMAC_TAG_LEN/64]; /* running total of L2-hash */
+};
+
+/*
* Constants and masks
*/
#define UINT64_C(x) x##ULL
} while (0)
#endif
-static void vhash_abort(struct vmac_ctx *ctx)
-{
- ctx->polytmp[0] = ctx->polykey[0] ;
- ctx->polytmp[1] = ctx->polykey[1] ;
- ctx->first_block_processed = 0;
-}
-
static u64 l3hash(u64 p1, u64 p2, u64 k1, u64 k2, u64 len)
{
u64 rh, rl, t, z = 0;
return rl;
}
-static void vhash_update(const unsigned char *m,
- unsigned int mbytes, /* Pos multiple of VMAC_NHBYTES */
- struct vmac_ctx *ctx)
+/* L1 and L2-hash one or more VMAC_NHBYTES-byte blocks */
+static void vhash_blocks(const struct vmac_tfm_ctx *tctx,
+ struct vmac_desc_ctx *dctx,
+ const __le64 *mptr, unsigned int blocks)
{
- u64 rh, rl, *mptr;
- const u64 *kptr = (u64 *)ctx->nhkey;
- int i;
- u64 ch, cl;
- u64 pkh = ctx->polykey[0];
- u64 pkl = ctx->polykey[1];
-
- if (!mbytes)
- return;
-
- BUG_ON(mbytes % VMAC_NHBYTES);
-
- mptr = (u64 *)m;
- i = mbytes / VMAC_NHBYTES; /* Must be non-zero */
-
- ch = ctx->polytmp[0];
- cl = ctx->polytmp[1];
-
- if (!ctx->first_block_processed) {
- ctx->first_block_processed = 1;
+ const u64 *kptr = tctx->nhkey;
+ const u64 pkh = tctx->polykey[0];
+ const u64 pkl = tctx->polykey[1];
+ u64 ch = dctx->polytmp[0];
+ u64 cl = dctx->polytmp[1];
+ u64 rh, rl;
+
+ if (!dctx->first_block_processed) {
+ dctx->first_block_processed = true;
nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
rh &= m62;
ADD128(ch, cl, rh, rl);
mptr += (VMAC_NHBYTES/sizeof(u64));
- i--;
+ blocks--;
}
- while (i--) {
+ while (blocks--) {
nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
rh &= m62;
poly_step(ch, cl, pkh, pkl, rh, rl);
mptr += (VMAC_NHBYTES/sizeof(u64));
}
- ctx->polytmp[0] = ch;
- ctx->polytmp[1] = cl;
+ dctx->polytmp[0] = ch;
+ dctx->polytmp[1] = cl;
}
-static u64 vhash(unsigned char m[], unsigned int mbytes,
- u64 *tagl, struct vmac_ctx *ctx)
+static int vmac_setkey(struct crypto_shash *tfm,
+ const u8 *key, unsigned int keylen)
{
- u64 rh, rl, *mptr;
- const u64 *kptr = (u64 *)ctx->nhkey;
- int i, remaining;
- u64 ch, cl;
- u64 pkh = ctx->polykey[0];
- u64 pkl = ctx->polykey[1];
-
- mptr = (u64 *)m;
- i = mbytes / VMAC_NHBYTES;
- remaining = mbytes % VMAC_NHBYTES;
-
- if (ctx->first_block_processed) {
- ch = ctx->polytmp[0];
- cl = ctx->polytmp[1];
- } else if (i) {
- nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, ch, cl);
- ch &= m62;
- ADD128(ch, cl, pkh, pkl);
- mptr += (VMAC_NHBYTES/sizeof(u64));
- i--;
- } else if (remaining) {
- nh_16(mptr, kptr, 2*((remaining+15)/16), ch, cl);
- ch &= m62;
- ADD128(ch, cl, pkh, pkl);
- mptr += (VMAC_NHBYTES/sizeof(u64));
- goto do_l3;
- } else {/* Empty String */
- ch = pkh; cl = pkl;
- goto do_l3;
- }
-
- while (i--) {
- nh_vmac_nhbytes(mptr, kptr, VMAC_NHBYTES/8, rh, rl);
- rh &= m62;
- poly_step(ch, cl, pkh, pkl, rh, rl);
- mptr += (VMAC_NHBYTES/sizeof(u64));
- }
- if (remaining) {
- nh_16(mptr, kptr, 2*((remaining+15)/16), rh, rl);
- rh &= m62;
- poly_step(ch, cl, pkh, pkl, rh, rl);
- }
-
-do_l3:
- vhash_abort(ctx);
- remaining *= 8;
- return l3hash(ch, cl, ctx->l3key[0], ctx->l3key[1], remaining);
-}
+ struct vmac_tfm_ctx *tctx = crypto_shash_ctx(tfm);
+ __be64 out[2];
+ u8 in[16] = { 0 };
+ unsigned int i;
+ int err;
-static u64 vmac(unsigned char m[], unsigned int mbytes,
- const unsigned char n[16], u64 *tagl,
- struct vmac_ctx_t *ctx)
-{
- u64 *in_n, *out_p;
- u64 p, h;
- int i;
-
- in_n = ctx->__vmac_ctx.cached_nonce;
- out_p = ctx->__vmac_ctx.cached_aes;
-
- i = n[15] & 1;
- if ((*(u64 *)(n+8) != in_n[1]) || (*(u64 *)(n) != in_n[0])) {
- in_n[0] = *(u64 *)(n);
- in_n[1] = *(u64 *)(n+8);
- ((unsigned char *)in_n)[15] &= 0xFE;
- crypto_cipher_encrypt_one(ctx->child,
- (unsigned char *)out_p, (unsigned char *)in_n);
-
- ((unsigned char *)in_n)[15] |= (unsigned char)(1-i);
+ if (keylen != VMAC_KEY_LEN) {
+ crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
}
- p = be64_to_cpup(out_p + i);
- h = vhash(m, mbytes, (u64 *)0, &ctx->__vmac_ctx);
- return le64_to_cpu(p + h);
-}
-static int vmac_set_key(unsigned char user_key[], struct vmac_ctx_t *ctx)
-{
- u64 in[2] = {0}, out[2];
- unsigned i;
- int err = 0;
-
- err = crypto_cipher_setkey(ctx->child, user_key, VMAC_KEY_LEN);
+ err = crypto_cipher_setkey(tctx->cipher, key, keylen);
if (err)
return err;
/* Fill nh key */
- ((unsigned char *)in)[0] = 0x80;
- for (i = 0; i < sizeof(ctx->__vmac_ctx.nhkey)/8; i += 2) {
- crypto_cipher_encrypt_one(ctx->child,
- (unsigned char *)out, (unsigned char *)in);
- ctx->__vmac_ctx.nhkey[i] = be64_to_cpup(out);
- ctx->__vmac_ctx.nhkey[i+1] = be64_to_cpup(out+1);
- ((unsigned char *)in)[15] += 1;
+ in[0] = 0x80;
+ for (i = 0; i < ARRAY_SIZE(tctx->nhkey); i += 2) {
+ crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
+ tctx->nhkey[i] = be64_to_cpu(out[0]);
+ tctx->nhkey[i+1] = be64_to_cpu(out[1]);
+ in[15]++;
}
/* Fill poly key */
- ((unsigned char *)in)[0] = 0xC0;
- in[1] = 0;
- for (i = 0; i < sizeof(ctx->__vmac_ctx.polykey)/8; i += 2) {
- crypto_cipher_encrypt_one(ctx->child,
- (unsigned char *)out, (unsigned char *)in);
- ctx->__vmac_ctx.polytmp[i] =
- ctx->__vmac_ctx.polykey[i] =
- be64_to_cpup(out) & mpoly;
- ctx->__vmac_ctx.polytmp[i+1] =
- ctx->__vmac_ctx.polykey[i+1] =
- be64_to_cpup(out+1) & mpoly;
- ((unsigned char *)in)[15] += 1;
+ in[0] = 0xC0;
+ in[15] = 0;
+ for (i = 0; i < ARRAY_SIZE(tctx->polykey); i += 2) {
+ crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
+ tctx->polykey[i] = be64_to_cpu(out[0]) & mpoly;
+ tctx->polykey[i+1] = be64_to_cpu(out[1]) & mpoly;
+ in[15]++;
}
/* Fill ip key */
- ((unsigned char *)in)[0] = 0xE0;
- in[1] = 0;
- for (i = 0; i < sizeof(ctx->__vmac_ctx.l3key)/8; i += 2) {
+ in[0] = 0xE0;
+ in[15] = 0;
+ for (i = 0; i < ARRAY_SIZE(tctx->l3key); i += 2) {
do {
- crypto_cipher_encrypt_one(ctx->child,
- (unsigned char *)out, (unsigned char *)in);
- ctx->__vmac_ctx.l3key[i] = be64_to_cpup(out);
- ctx->__vmac_ctx.l3key[i+1] = be64_to_cpup(out+1);
- ((unsigned char *)in)[15] += 1;
- } while (ctx->__vmac_ctx.l3key[i] >= p64
- || ctx->__vmac_ctx.l3key[i+1] >= p64);
+ crypto_cipher_encrypt_one(tctx->cipher, (u8 *)out, in);
+ tctx->l3key[i] = be64_to_cpu(out[0]);
+ tctx->l3key[i+1] = be64_to_cpu(out[1]);
+ in[15]++;
+ } while (tctx->l3key[i] >= p64 || tctx->l3key[i+1] >= p64);
}
- /* Invalidate nonce/aes cache and reset other elements */
- ctx->__vmac_ctx.cached_nonce[0] = (u64)-1; /* Ensure illegal nonce */
- ctx->__vmac_ctx.cached_nonce[1] = (u64)0; /* Ensure illegal nonce */
- ctx->__vmac_ctx.first_block_processed = 0;
-
- return err;
+ return 0;
}
-static int vmac_setkey(struct crypto_shash *parent,
- const u8 *key, unsigned int keylen)
+static int vmac_init(struct shash_desc *desc)
{
- struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
+ const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+ struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
- if (keylen != VMAC_KEY_LEN) {
- crypto_shash_set_flags(parent, CRYPTO_TFM_RES_BAD_KEY_LEN);
- return -EINVAL;
- }
-
- return vmac_set_key((u8 *)key, ctx);
-}
-
-static int vmac_init(struct shash_desc *pdesc)
-{
+ dctx->partial_size = 0;
+ dctx->first_block_processed = false;
+ memcpy(dctx->polytmp, tctx->polykey, sizeof(dctx->polytmp));
return 0;
}
-static int vmac_update(struct shash_desc *pdesc, const u8 *p,
- unsigned int len)
+static int vmac_update(struct shash_desc *desc, const u8 *p, unsigned int len)
{
- struct crypto_shash *parent = pdesc->tfm;
- struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
- int expand;
- int min;
-
- expand = VMAC_NHBYTES - ctx->partial_size > 0 ?
- VMAC_NHBYTES - ctx->partial_size : 0;
-
- min = len < expand ? len : expand;
-
- memcpy(ctx->partial + ctx->partial_size, p, min);
- ctx->partial_size += min;
-
- if (len < expand)
- return 0;
-
- vhash_update(ctx->partial, VMAC_NHBYTES, &ctx->__vmac_ctx);
- ctx->partial_size = 0;
-
- len -= expand;
- p += expand;
+ const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+ struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
+ unsigned int n;
+
+ if (dctx->partial_size) {
+ n = min(len, VMAC_NHBYTES - dctx->partial_size);
+ memcpy(&dctx->partial[dctx->partial_size], p, n);
+ dctx->partial_size += n;
+ p += n;
+ len -= n;
+ if (dctx->partial_size == VMAC_NHBYTES) {
+ vhash_blocks(tctx, dctx, dctx->partial_words, 1);
+ dctx->partial_size = 0;
+ }
+ }
- if (len % VMAC_NHBYTES) {
- memcpy(ctx->partial, p + len - (len % VMAC_NHBYTES),
- len % VMAC_NHBYTES);
- ctx->partial_size = len % VMAC_NHBYTES;
+ if (len >= VMAC_NHBYTES) {
+ n = round_down(len, VMAC_NHBYTES);
+ /* TODO: 'p' may be misaligned here */
+ vhash_blocks(tctx, dctx, (const __le64 *)p, n / VMAC_NHBYTES);
+ p += n;
+ len -= n;
}
- vhash_update(p, len - len % VMAC_NHBYTES, &ctx->__vmac_ctx);
+ if (len) {
+ memcpy(dctx->partial, p, len);
+ dctx->partial_size = len;
+ }
return 0;
}
-static int vmac_final(struct shash_desc *pdesc, u8 *out)
+static u64 vhash_final(const struct vmac_tfm_ctx *tctx,
+ struct vmac_desc_ctx *dctx)
{
- struct crypto_shash *parent = pdesc->tfm;
- struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
- vmac_t mac;
- u8 nonce[16] = {};
-
- /* vmac() ends up accessing outside the array bounds that
- * we specify. In appears to access up to the next 2-word
- * boundary. We'll just be uber cautious and zero the
- * unwritten bytes in the buffer.
- */
- if (ctx->partial_size) {
- memset(ctx->partial + ctx->partial_size, 0,
- VMAC_NHBYTES - ctx->partial_size);
+ unsigned int partial = dctx->partial_size;
+ u64 ch = dctx->polytmp[0];
+ u64 cl = dctx->polytmp[1];
+
+ /* L1 and L2-hash the final block if needed */
+ if (partial) {
+ /* Zero-pad to next 128-bit boundary */
+ unsigned int n = round_up(partial, 16);
+ u64 rh, rl;
+
+ memset(&dctx->partial[partial], 0, n - partial);
+ nh_16(dctx->partial_words, tctx->nhkey, n / 8, rh, rl);
+ rh &= m62;
+ if (dctx->first_block_processed)
+ poly_step(ch, cl, tctx->polykey[0], tctx->polykey[1],
+ rh, rl);
+ else
+ ADD128(ch, cl, rh, rl);
}
- mac = vmac(ctx->partial, ctx->partial_size, nonce, NULL, ctx);
- memcpy(out, &mac, sizeof(vmac_t));
- memzero_explicit(&mac, sizeof(vmac_t));
- memset(&ctx->__vmac_ctx, 0, sizeof(struct vmac_ctx));
- ctx->partial_size = 0;
+
+ /* L3-hash the 128-bit output of L2-hash */
+ return l3hash(ch, cl, tctx->l3key[0], tctx->l3key[1], partial * 8);
+}
+
+static int vmac_final(struct shash_desc *desc, u8 *out)
+{
+ const struct vmac_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
+ struct vmac_desc_ctx *dctx = shash_desc_ctx(desc);
+ static const u8 nonce[16] = {}; /* TODO: this is insecure */
+ union {
+ u8 bytes[16];
+ __be64 pads[2];
+ } block;
+ int index;
+ u64 hash, pad;
+
+ /* Finish calculating the VHASH of the message */
+ hash = vhash_final(tctx, dctx);
+
+ /* Generate pseudorandom pad by encrypting the nonce */
+ memcpy(&block, nonce, 16);
+ index = block.bytes[15] & 1;
+ block.bytes[15] &= ~1;
+ crypto_cipher_encrypt_one(tctx->cipher, block.bytes, block.bytes);
+ pad = be64_to_cpu(block.pads[index]);
+
+ /* The VMAC is the sum of VHASH and the pseudorandom pad */
+ put_unaligned_le64(hash + pad, out);
return 0;
}
static int vmac_init_tfm(struct crypto_tfm *tfm)
{
- struct crypto_cipher *cipher;
- struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
- struct vmac_ctx_t *ctx = crypto_tfm_ctx(tfm);
+ struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
+ struct crypto_cipher *cipher;
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
- ctx->child = cipher;
+ tctx->cipher = cipher;
return 0;
}
static void vmac_exit_tfm(struct crypto_tfm *tfm)
{
- struct vmac_ctx_t *ctx = crypto_tfm_ctx(tfm);
- crypto_free_cipher(ctx->child);
+ struct vmac_tfm_ctx *tctx = crypto_tfm_ctx(tfm);
+
+ crypto_free_cipher(tctx->cipher);
}
static int vmac_create(struct crypto_template *tmpl, struct rtattr **tb)
if (IS_ERR(alg))
return PTR_ERR(alg);
+ err = -EINVAL;
+ if (alg->cra_blocksize != 16)
+ goto out_put_alg;
+
inst = shash_alloc_instance("vmac", alg);
err = PTR_ERR(inst);
if (IS_ERR(inst))
inst->alg.base.cra_blocksize = alg->cra_blocksize;
inst->alg.base.cra_alignmask = alg->cra_alignmask;
- inst->alg.digestsize = sizeof(vmac_t);
- inst->alg.base.cra_ctxsize = sizeof(struct vmac_ctx_t);
+ inst->alg.base.cra_ctxsize = sizeof(struct vmac_tfm_ctx);
inst->alg.base.cra_init = vmac_init_tfm;
inst->alg.base.cra_exit = vmac_exit_tfm;
+ inst->alg.descsize = sizeof(struct vmac_desc_ctx);
+ inst->alg.digestsize = VMAC_TAG_LEN / 8;
inst->alg.init = vmac_init;
inst->alg.update = vmac_update;
inst->alg.final = vmac_final;
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