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ICP: AES-GCM: Unify gcm_init_ctx() and gmac_init_ctx()
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gmac_init_ctx() duplicates most of the code in gcm_int_ctx() while
it just needs to set its own IV length and AAD tag length.

Introduce gcm_init_ctx_impl() which handles the GCM and GMAC
differences while reusing the duplicated code.

While here, fix a flaw where the AVX implementation would accept a
context using a byte swapped key schedule which it could not
handle. Also constify the IV and AAD pointers passed to
gcm_init{,_avx}().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes openzfs#14529
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@AttilaFueloep @lundman
AttilaFueloep authored and lundman committed Mar 16, 2023
1 parent 9d2d88b commit d24567b
Showing 1 changed file with 103 additions and 104 deletions.
207 changes: 103 additions & 104 deletions module/icp/algs/modes/gcm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
*/

#include <sys/zfs_context.h>
#include <sys/cmn_err.h>
#include <modes/modes.h>
#include <sys/crypto/common.h>
#include <sys/crypto/icp.h>
Expand All @@ -49,6 +50,11 @@
static uint32_t icp_gcm_impl = IMPL_FASTEST;
static uint32_t user_sel_impl = IMPL_FASTEST;

static inline int gcm_init_ctx_impl(boolean_t, gcm_ctx_t *, char *, size_t,
int (*)(const void *, const uint8_t *, uint8_t *),
void (*)(uint8_t *, uint8_t *),
void (*)(uint8_t *, uint8_t *));

#ifdef CAN_USE_GCM_ASM
/* Does the architecture we run on support the MOVBE instruction? */
boolean_t gcm_avx_can_use_movbe = B_FALSE;
Expand All @@ -71,7 +77,7 @@ static int gcm_mode_encrypt_contiguous_blocks_avx(gcm_ctx_t *, char *, size_t,

static int gcm_encrypt_final_avx(gcm_ctx_t *, crypto_data_t *, size_t);
static int gcm_decrypt_final_avx(gcm_ctx_t *, crypto_data_t *, size_t);
static int gcm_init_avx(gcm_ctx_t *, unsigned char *, size_t, unsigned char *,
static int gcm_init_avx(gcm_ctx_t *, const uint8_t *, size_t, const uint8_t *,
size_t, size_t);
#endif /* ifdef CAN_USE_GCM_ASM */

Expand Down Expand Up @@ -478,7 +484,7 @@ gcm_validate_args(CK_AES_GCM_PARAMS *gcm_param)
}

static void
gcm_format_initial_blocks(uchar_t *iv, ulong_t iv_len,
gcm_format_initial_blocks(const uint8_t *iv, ulong_t iv_len,
gcm_ctx_t *ctx, size_t block_size,
void (*copy_block)(uint8_t *, uint8_t *),
void (*xor_block)(uint8_t *, uint8_t *))
Expand Down Expand Up @@ -527,8 +533,8 @@ gcm_format_initial_blocks(uchar_t *iv, ulong_t iv_len,
}

static int
gcm_init(gcm_ctx_t *ctx, unsigned char *iv, size_t iv_len,
unsigned char *auth_data, size_t auth_data_len, size_t block_size,
gcm_init(gcm_ctx_t *ctx, const uint8_t *iv, size_t iv_len,
const uint8_t *auth_data, size_t auth_data_len, size_t block_size,
int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
void (*copy_block)(uint8_t *, uint8_t *),
void (*xor_block)(uint8_t *, uint8_t *))
Expand Down Expand Up @@ -587,40 +593,82 @@ gcm_init(gcm_ctx_t *ctx, unsigned char *iv, size_t iv_len,
/*
* The following function is called at encrypt or decrypt init time
* for AES GCM mode.
*
* Init the GCM context struct. Handle the cycle and avx implementations here.
*/
int
gcm_init_ctx(gcm_ctx_t *gcm_ctx, char *param, size_t block_size,
int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
void (*copy_block)(uint8_t *, uint8_t *),
void (*xor_block)(uint8_t *, uint8_t *))
{
int rv;
return (gcm_init_ctx_impl(B_FALSE, gcm_ctx, param, block_size,
encrypt_block, copy_block, xor_block));
}

/*
* The following function is called at encrypt or decrypt init time
* for AES GMAC mode.
*/
int
gmac_init_ctx(gcm_ctx_t *gcm_ctx, char *param, size_t block_size,
int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
void (*copy_block)(uint8_t *, uint8_t *),
void (*xor_block)(uint8_t *, uint8_t *))
{
return (gcm_init_ctx_impl(B_TRUE, gcm_ctx, param, block_size,
encrypt_block, copy_block, xor_block));
}

/*
* Init the GCM context struct. Handle the cycle and avx implementations here.
* Initialization of a GMAC context differs slightly from a GCM context.
*/
static inline int
gcm_init_ctx_impl(boolean_t gmac_mode, gcm_ctx_t *gcm_ctx, char *param,
size_t block_size, int (*encrypt_block)(const void *, const uint8_t *,
uint8_t *), void (*copy_block)(uint8_t *, uint8_t *),
void (*xor_block)(uint8_t *, uint8_t *))
{
CK_AES_GCM_PARAMS *gcm_param;
int rv = CRYPTO_SUCCESS;
size_t tag_len, iv_len;

if (param != NULL) {
gcm_param = (CK_AES_GCM_PARAMS *)(void *)param;

if ((rv = gcm_validate_args(gcm_param)) != 0) {
return (rv);
}
if (gmac_mode == B_FALSE) {
/* GCM mode. */
if ((rv = gcm_validate_args(gcm_param)) != 0) {
return (rv);
}
gcm_ctx->gcm_flags |= GCM_MODE;

gcm_ctx->gcm_tag_len = gcm_param->ulTagBits;
gcm_ctx->gcm_tag_len >>= 3;
size_t tbits = gcm_param->ulTagBits;
tag_len = CRYPTO_BITS2BYTES(tbits);
iv_len = gcm_param->ulIvLen;
} else {
/* GMAC mode. */
gcm_ctx->gcm_flags |= GMAC_MODE;
tag_len = CRYPTO_BITS2BYTES(AES_GMAC_TAG_BITS);
iv_len = AES_GMAC_IV_LEN;
}
gcm_ctx->gcm_tag_len = tag_len;
gcm_ctx->gcm_processed_data_len = 0;

/* these values are in bits */
gcm_ctx->gcm_len_a_len_c[0]
= htonll(CRYPTO_BYTES2BITS(gcm_param->ulAADLen));

rv = CRYPTO_SUCCESS;
gcm_ctx->gcm_flags |= GCM_MODE;
} else {
return (CRYPTO_MECHANISM_PARAM_INVALID);
}

const uint8_t *iv = (const uint8_t *)gcm_param->pIv;
const uint8_t *aad = (const uint8_t *)gcm_param->pAAD;
size_t aad_len = gcm_param->ulAADLen;

#ifdef CAN_USE_GCM_ASM
boolean_t needs_bswap =
((aes_key_t *)gcm_ctx->gcm_keysched)->ops->needs_byteswap;

if (GCM_IMPL_READ(icp_gcm_impl) != IMPL_CYCLE) {
gcm_ctx->gcm_use_avx = GCM_IMPL_USE_AVX;
} else {
Expand All @@ -629,96 +677,41 @@ gcm_init_ctx(gcm_ctx_t *gcm_ctx, char *param, size_t block_size,
* non-avx contexts alternately.
*/
gcm_ctx->gcm_use_avx = gcm_toggle_avx();
/*
* We don't handle byte swapped key schedules in the avx
* code path.
*/
aes_key_t *ks = (aes_key_t *)gcm_ctx->gcm_keysched;
if (ks->ops->needs_byteswap == B_TRUE) {

/* The avx impl. doesn't handle byte swapped key schedules. */
if (gcm_ctx->gcm_use_avx == B_TRUE && needs_bswap == B_TRUE) {
gcm_ctx->gcm_use_avx = B_FALSE;
}
/* Use the MOVBE and the BSWAP variants alternately. */
if (gcm_ctx->gcm_use_avx == B_TRUE &&
/*
* If this is a GCM context, use the MOVBE and the BSWAP
* variants alternately. GMAC contexts code paths do not
* use the MOVBE instruction.
*/
if (gcm_ctx->gcm_use_avx == B_TRUE && gmac_mode == B_FALSE &&
zfs_movbe_available() == B_TRUE) {
(void) atomic_toggle_boolean_nv(
(volatile boolean_t *)&gcm_avx_can_use_movbe);
}
}
/* Allocate Htab memory as needed. */
if (gcm_ctx->gcm_use_avx == B_TRUE) {
size_t htab_len = gcm_simd_get_htab_size(gcm_ctx->gcm_use_avx);

if (htab_len == 0) {
return (CRYPTO_MECHANISM_PARAM_INVALID);
}
gcm_ctx->gcm_htab_len = htab_len;
gcm_ctx->gcm_Htable =
kmem_alloc(htab_len, KM_SLEEP);

if (gcm_ctx->gcm_Htable == NULL) {
return (CRYPTO_HOST_MEMORY);
}
}
/* Avx and non avx context initialization differs from here on. */
if (gcm_ctx->gcm_use_avx == B_FALSE) {
#endif /* ifdef CAN_USE_GCM_ASM */
if (gcm_init(gcm_ctx, gcm_param->pIv, gcm_param->ulIvLen,
gcm_param->pAAD, gcm_param->ulAADLen, block_size,
encrypt_block, copy_block, xor_block) != 0) {
rv = CRYPTO_MECHANISM_PARAM_INVALID;
}
#ifdef CAN_USE_GCM_ASM
} else {
if (gcm_init_avx(gcm_ctx, gcm_param->pIv, gcm_param->ulIvLen,
gcm_param->pAAD, gcm_param->ulAADLen, block_size) != 0) {
rv = CRYPTO_MECHANISM_PARAM_INVALID;
}
}
#endif /* ifdef CAN_USE_GCM_ASM */

return (rv);
}

int
gmac_init_ctx(gcm_ctx_t *gcm_ctx, char *param, size_t block_size,
int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
void (*copy_block)(uint8_t *, uint8_t *),
void (*xor_block)(uint8_t *, uint8_t *))
{
int rv;
CK_AES_GMAC_PARAMS *gmac_param;

if (param != NULL) {
gmac_param = (CK_AES_GMAC_PARAMS *)(void *)param;

gcm_ctx->gcm_tag_len = CRYPTO_BITS2BYTES(AES_GMAC_TAG_BITS);
gcm_ctx->gcm_processed_data_len = 0;

/* these values are in bits */
gcm_ctx->gcm_len_a_len_c[0]
= htonll(CRYPTO_BYTES2BITS(gmac_param->ulAADLen));

rv = CRYPTO_SUCCESS;
gcm_ctx->gcm_flags |= GMAC_MODE;
} else {
return (CRYPTO_MECHANISM_PARAM_INVALID);
}

#ifdef CAN_USE_GCM_ASM
/*
* Handle the "cycle" implementation by creating avx and non avx
* contexts alternately.
* We don't handle byte swapped key schedules in the avx code path,
* still they could be created by the aes generic implementation.
* Make sure not to use them since we'll corrupt data if we do.
*/
if (GCM_IMPL_READ(icp_gcm_impl) != IMPL_CYCLE) {
gcm_ctx->gcm_use_avx = GCM_IMPL_USE_AVX;
} else {
gcm_ctx->gcm_use_avx = gcm_toggle_avx();
}
/* We don't handle byte swapped key schedules in the avx code path. */
aes_key_t *ks = (aes_key_t *)gcm_ctx->gcm_keysched;
if (ks->ops->needs_byteswap == B_TRUE) {
if (gcm_ctx->gcm_use_avx == B_TRUE && needs_bswap == B_TRUE) {
gcm_ctx->gcm_use_avx = B_FALSE;

cmn_err_once(CE_WARN,
"ICP: Can't use the aes generic or cycle implementations "
"in combination with the gcm avx implementation!");
cmn_err_once(CE_WARN,
"ICP: Falling back to a compatible implementation, "
"aes-gcm performance will likely be degraded.");
cmn_err_once(CE_WARN,
"ICP: Choose at least the x86_64 aes implementation to "
"restore performance.");
}

/* Allocate Htab memory as needed. */
if (gcm_ctx->gcm_use_avx == B_TRUE) {
size_t htab_len = gcm_simd_get_htab_size(gcm_ctx->gcm_use_avx);
Expand All @@ -734,19 +727,17 @@ gmac_init_ctx(gcm_ctx_t *gcm_ctx, char *param, size_t block_size,
return (CRYPTO_HOST_MEMORY);
}
}

/* Avx and non avx context initialization differs from here on. */
if (gcm_ctx->gcm_use_avx == B_FALSE) {
#endif /* ifdef CAN_USE_GCM_ASM */
if (gcm_init(gcm_ctx, gmac_param->pIv, AES_GMAC_IV_LEN,
gmac_param->pAAD, gmac_param->ulAADLen, block_size,
encrypt_block, copy_block, xor_block) != 0) {
#endif /* ifdef CAN_USE_GCM_ASM */
if (gcm_init(gcm_ctx, iv, iv_len, aad, aad_len, block_size,
encrypt_block, copy_block, xor_block) != CRYPTO_SUCCESS) {
rv = CRYPTO_MECHANISM_PARAM_INVALID;
}
#ifdef CAN_USE_GCM_ASM
} else {
if (gcm_init_avx(gcm_ctx, gmac_param->pIv, AES_GMAC_IV_LEN,
gmac_param->pAAD, gmac_param->ulAADLen, block_size) != 0) {
if (gcm_init_avx(gcm_ctx, iv, iv_len, aad, aad_len,
block_size) != CRYPTO_SUCCESS) {
rv = CRYPTO_MECHANISM_PARAM_INVALID;
}
}
Expand Down Expand Up @@ -1189,6 +1180,8 @@ gcm_mode_encrypt_contiguous_blocks_avx(gcm_ctx_t *ctx, char *data,
int rv = CRYPTO_SUCCESS;

ASSERT(block_size == GCM_BLOCK_LEN);
ASSERT3S(((aes_key_t *)ctx->gcm_keysched)->ops->needs_byteswap, ==,
B_FALSE);
/*
* If the last call left an incomplete block, try to fill
* it first.
Expand Down Expand Up @@ -1333,6 +1326,8 @@ gcm_encrypt_final_avx(gcm_ctx_t *ctx, crypto_data_t *out, size_t block_size)
int rv;

ASSERT(block_size == GCM_BLOCK_LEN);
ASSERT3S(((aes_key_t *)ctx->gcm_keysched)->ops->needs_byteswap, ==,
B_FALSE);

if (out->cd_length < (rem_len + ctx->gcm_tag_len)) {
return (CRYPTO_DATA_LEN_RANGE);
Expand Down Expand Up @@ -1388,6 +1383,8 @@ gcm_decrypt_final_avx(gcm_ctx_t *ctx, crypto_data_t *out, size_t block_size)
{
ASSERT3U(ctx->gcm_processed_data_len, ==, ctx->gcm_pt_buf_len);
ASSERT3U(block_size, ==, 16);
ASSERT3S(((aes_key_t *)ctx->gcm_keysched)->ops->needs_byteswap, ==,
B_FALSE);

size_t chunk_size = (size_t)GCM_CHUNK_SIZE_READ;
size_t pt_len = ctx->gcm_processed_data_len - ctx->gcm_tag_len;
Expand Down Expand Up @@ -1493,18 +1490,20 @@ gcm_decrypt_final_avx(gcm_ctx_t *ctx, crypto_data_t *out, size_t block_size)
* initial counter block.
*/
static int
gcm_init_avx(gcm_ctx_t *ctx, unsigned char *iv, size_t iv_len,
unsigned char *auth_data, size_t auth_data_len, size_t block_size)
gcm_init_avx(gcm_ctx_t *ctx, const uint8_t *iv, size_t iv_len,
const uint8_t *auth_data, size_t auth_data_len, size_t block_size)
{
uint8_t *cb = (uint8_t *)ctx->gcm_cb;
uint64_t *H = ctx->gcm_H;
const void *keysched = ((aes_key_t *)ctx->gcm_keysched)->encr_ks.ks32;
int aes_rounds = ((aes_key_t *)ctx->gcm_keysched)->nr;
uint8_t *datap = auth_data;
const uint8_t *datap = auth_data;
size_t chunk_size = (size_t)GCM_CHUNK_SIZE_READ;
size_t bleft;

ASSERT(block_size == GCM_BLOCK_LEN);
ASSERT3S(((aes_key_t *)ctx->gcm_keysched)->ops->needs_byteswap, ==,
B_FALSE);

/* Init H (encrypt zero block) and create the initial counter block. */
memset(ctx->gcm_ghash, 0, sizeof (ctx->gcm_ghash));
Expand Down

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