[v5 PATCH 7/7] crypto: stm32 - Save and restore between each request

From: Herbert Xu
Date: Sat Mar 04 2023 - 04:38:05 EST

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The Crypto API hashing paradigm requires the hardware state to
be exported between *each* request because multiple unrelated
hashes may be processed concurrently.

The stm32 hardware is capable of producing the hardware hashing
state but it was only doing it in the export function. This is
not only broken for export as you can't export a kernel pointer
and reimport it, but it also means that concurrent hashing was
fundamentally broken.

Fix this by moving the saving and restoring of hardware hash
state between each and every hashing request.

Also change the emptymsg check in stm32_hash_copy_hash to rely
on whether we have any existing hash state, rather than whether
this particular update request is empty.

Fixes: 8a1012d3f2ab ("crypto: stm32 - Support for STM32 HASH module")
Reported-by: Li kunyu <kunyu@xxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---

drivers/crypto/stm32/stm32-hash.c | 172 +++++++++++++-------------------------
1 file changed, 62 insertions(+), 110 deletions(-)

diff --git a/drivers/crypto/stm32/stm32-hash.c b/drivers/crypto/stm32/stm32-hash.c
index fd9189472235..85da2aa93017 100644
--- a/drivers/crypto/stm32/stm32-hash.c
+++ b/drivers/crypto/stm32/stm32-hash.c
@@ -95,6 +95,7 @@
#define HASH_FLAGS_SHA1 BIT(19)
#define HASH_FLAGS_SHA224 BIT(20)
#define HASH_FLAGS_SHA256 BIT(21)
+#define HASH_FLAGS_EMPTY BIT(22)
#define HASH_FLAGS_HMAC BIT(23)

#define HASH_OP_UPDATE 1
@@ -134,7 +135,7 @@ struct stm32_hash_state {
u8 buffer[HASH_BUFLEN] __aligned(4);

/* hash state */
- u32 *hw_context;
+ u32 hw_context[3 + HASH_CSR_REGISTER_NUMBER];
};

struct stm32_hash_request_ctx {
@@ -314,8 +315,11 @@ static void stm32_hash_write_ctrl(struct stm32_hash_dev *hdev, int bufcnt)
* On the Ux500 we need to set a special flag to indicate that
* the message is zero length.
*/
- if (hdev->pdata->ux500 && bufcnt == 0)
+ if (hdev->pdata->ux500 && bufcnt == 0 &&
+ (state->flags & HASH_FLAGS_FINAL)) {
reg |= HASH_CR_UX500_EMPTYMSG;
+ state->flags |= HASH_FLAGS_EMPTY;
+ }

if (!hdev->polled)
stm32_hash_write(hdev, HASH_IMR, HASH_DCIE);
@@ -419,7 +423,9 @@ static int stm32_hash_update_cpu(struct stm32_hash_dev *hdev)
{
struct stm32_hash_request_ctx *rctx = ahash_request_ctx(hdev->req);
struct stm32_hash_state *state = &rctx->state;
+ u32 *preg = state->hw_context;
int bufcnt, err = 0, final;
+ int i;

dev_dbg(hdev->dev, "%s flags %x\n", __func__, state->flags);

@@ -440,9 +446,24 @@ static int stm32_hash_update_cpu(struct stm32_hash_dev *hdev)
if (final) {
bufcnt = state->bufcnt;
state->bufcnt = 0;
- err = stm32_hash_xmit_cpu(hdev, state->buffer, bufcnt, 1);
+ return stm32_hash_xmit_cpu(hdev, state->buffer, bufcnt, 1);
}

+ if (!(hdev->flags & HASH_FLAGS_INIT))
+ return 0;
+
+ if (stm32_hash_wait_busy(hdev))
+ return -ETIMEDOUT;
+
+ if (!hdev->pdata->ux500)
+ *preg++ = stm32_hash_read(hdev, HASH_IMR);
+ *preg++ = stm32_hash_read(hdev, HASH_STR);
+ *preg++ = stm32_hash_read(hdev, HASH_CR);
+ for (i = 0; i < HASH_CSR_REGISTER_NUMBER; i++)
+ *preg++ = stm32_hash_read(hdev, HASH_CSR(i));
+
+ state->flags |= HASH_FLAGS_INIT;
+
return err;
}

@@ -824,7 +845,7 @@ static void stm32_hash_copy_hash(struct ahash_request *req)
__be32 *hash = (void *)rctx->digest;
unsigned int i, hashsize;

- if (hdev->pdata->broken_emptymsg && !req->nbytes)
+ if (hdev->pdata->broken_emptymsg && (state->flags & HASH_FLAGS_EMPTY))
return stm32_hash_emptymsg_fallback(req);

switch (state->flags & HASH_FLAGS_ALGO_MASK) {
@@ -874,11 +895,6 @@ static void stm32_hash_finish_req(struct ahash_request *req, int err)
if (!err && (HASH_FLAGS_FINAL & hdev->flags)) {
stm32_hash_copy_hash(req);
err = stm32_hash_finish(req);
- hdev->flags &= ~(HASH_FLAGS_FINAL | HASH_FLAGS_CPU |
- HASH_FLAGS_INIT | HASH_FLAGS_DMA_READY |
- HASH_FLAGS_OUTPUT_READY | HASH_FLAGS_HMAC |
- HASH_FLAGS_HMAC_INIT | HASH_FLAGS_HMAC_FINAL |
- HASH_FLAGS_HMAC_KEY);
}

pm_runtime_mark_last_busy(hdev->dev);
@@ -887,66 +903,54 @@ static void stm32_hash_finish_req(struct ahash_request *req, int err)
crypto_finalize_hash_request(hdev->engine, req, err);
}

-static int stm32_hash_hw_init(struct stm32_hash_dev *hdev,
- struct stm32_hash_request_ctx *rctx)
-{
- pm_runtime_get_sync(hdev->dev);
-
- if (!(HASH_FLAGS_INIT & hdev->flags)) {
- stm32_hash_write(hdev, HASH_CR, HASH_CR_INIT);
- stm32_hash_write(hdev, HASH_STR, 0);
- stm32_hash_write(hdev, HASH_DIN, 0);
- stm32_hash_write(hdev, HASH_IMR, 0);
- }
-
- return 0;
-}
-
-static int stm32_hash_one_request(struct crypto_engine *engine, void *areq);
-static int stm32_hash_prepare_req(struct crypto_engine *engine, void *areq);
-
static int stm32_hash_handle_queue(struct stm32_hash_dev *hdev,
struct ahash_request *req)
{
return crypto_transfer_hash_request_to_engine(hdev->engine, req);
}

-static int stm32_hash_prepare_req(struct crypto_engine *engine, void *areq)
+static int stm32_hash_one_request(struct crypto_engine *engine, void *areq)
{
struct ahash_request *req = container_of(areq, struct ahash_request,
base);
struct stm32_hash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ struct stm32_hash_request_ctx *rctx = ahash_request_ctx(req);
struct stm32_hash_dev *hdev = stm32_hash_find_dev(ctx);
- struct stm32_hash_request_ctx *rctx;
+ struct stm32_hash_state *state = &rctx->state;
+ int err = 0;

if (!hdev)
return -ENODEV;

- hdev->req = req;
-
- rctx = ahash_request_ctx(req);
-
dev_dbg(hdev->dev, "processing new req, op: %lu, nbytes %d\n",
rctx->op, req->nbytes);

- return stm32_hash_hw_init(hdev, rctx);
-}
+ pm_runtime_get_sync(hdev->dev);

-static int stm32_hash_one_request(struct crypto_engine *engine, void *areq)
-{
- struct ahash_request *req = container_of(areq, struct ahash_request,
- base);
- struct stm32_hash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
- struct stm32_hash_dev *hdev = stm32_hash_find_dev(ctx);
- struct stm32_hash_request_ctx *rctx;
- int err = 0;
+ hdev->req = req;
+ hdev->flags = 0;
+
+ if (state->flags & HASH_FLAGS_INIT) {
+ u32 *preg = rctx->state.hw_context;
+ u32 reg;
+ int i;
+
+ if (!hdev->pdata->ux500)
+ stm32_hash_write(hdev, HASH_IMR, *preg++);
+ stm32_hash_write(hdev, HASH_STR, *preg++);
+ stm32_hash_write(hdev, HASH_CR, *preg);
+ reg = *preg++ | HASH_CR_INIT;
+ stm32_hash_write(hdev, HASH_CR, reg);

- if (!hdev)
- return -ENODEV;
+ for (i = 0; i < HASH_CSR_REGISTER_NUMBER; i++)
+ stm32_hash_write(hdev, HASH_CSR(i), *preg++);

- hdev->req = req;
+ hdev->flags |= HASH_FLAGS_INIT;

- rctx = ahash_request_ctx(req);
+ if (state->flags & HASH_FLAGS_HMAC)
+ hdev->flags |= HASH_FLAGS_HMAC |
+ HASH_FLAGS_HMAC_KEY;
+ }

if (rctx->op == HASH_OP_UPDATE)
err = stm32_hash_update_req(hdev);
@@ -1034,34 +1038,8 @@ static int stm32_hash_digest(struct ahash_request *req)
static int stm32_hash_export(struct ahash_request *req, void *out)
{
struct stm32_hash_request_ctx *rctx = ahash_request_ctx(req);
- struct stm32_hash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
- struct stm32_hash_dev *hdev = stm32_hash_find_dev(ctx);
- struct stm32_hash_state *state = &rctx->state;
- u32 *preg;
- unsigned int i;
- int ret;
-
- pm_runtime_get_sync(hdev->dev);
-
- ret = stm32_hash_wait_busy(hdev);
- if (ret)
- return ret;
-
- state->hw_context = kmalloc_array(3 + HASH_CSR_REGISTER_NUMBER,
- sizeof(u32), GFP_KERNEL);
- preg = state->hw_context;

- if (!hdev->pdata->ux500)
- *preg++ = stm32_hash_read(hdev, HASH_IMR);
- *preg++ = stm32_hash_read(hdev, HASH_STR);
- *preg++ = stm32_hash_read(hdev, HASH_CR);
- for (i = 0; i < HASH_CSR_REGISTER_NUMBER; i++)
- *preg++ = stm32_hash_read(hdev, HASH_CSR(i));
-
- pm_runtime_mark_last_busy(hdev->dev);
- pm_runtime_put_autosuspend(hdev->dev);
-
- memcpy(out, rctx, sizeof(*rctx));
+ memcpy(out, &rctx->state, sizeof(rctx->state));

return 0;
}
@@ -1069,33 +1047,9 @@ static int stm32_hash_export(struct ahash_request *req, void *out)
static int stm32_hash_import(struct ahash_request *req, const void *in)
{
struct stm32_hash_request_ctx *rctx = ahash_request_ctx(req);
- struct stm32_hash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
- struct stm32_hash_dev *hdev = stm32_hash_find_dev(ctx);
- struct stm32_hash_state *state = &rctx->state;
- const u32 *preg = in;
- u32 reg;
- unsigned int i;
-
- memcpy(rctx, in, sizeof(*rctx));
-
- preg = state->hw_context;
-
- pm_runtime_get_sync(hdev->dev);
-
- if (!hdev->pdata->ux500)
- stm32_hash_write(hdev, HASH_IMR, *preg++);
- stm32_hash_write(hdev, HASH_STR, *preg++);
- stm32_hash_write(hdev, HASH_CR, *preg);
- reg = *preg++ | HASH_CR_INIT;
- stm32_hash_write(hdev, HASH_CR, reg);
-
- for (i = 0; i < HASH_CSR_REGISTER_NUMBER; i++)
- stm32_hash_write(hdev, HASH_CSR(i), *preg++);
-
- pm_runtime_mark_last_busy(hdev->dev);
- pm_runtime_put_autosuspend(hdev->dev);

- kfree(state->hw_context);
+ stm32_hash_init(req);
+ memcpy(&rctx->state, in, sizeof(rctx->state));

return 0;
}
@@ -1152,8 +1106,6 @@ static int stm32_hash_cra_init_algs(struct crypto_tfm *tfm,
ctx->flags |= HASH_FLAGS_HMAC;

ctx->enginectx.op.do_one_request = stm32_hash_one_request;
- ctx->enginectx.op.prepare_request = stm32_hash_prepare_req;
- ctx->enginectx.op.unprepare_request = NULL;

return stm32_hash_init_fallback(tfm);
}
@@ -1245,7 +1197,7 @@ static struct ahash_alg algs_md5[] = {
.import = stm32_hash_import,
.halg = {
.digestsize = MD5_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "md5",
.cra_driver_name = "stm32-md5",
@@ -1272,7 +1224,7 @@ static struct ahash_alg algs_md5[] = {
.setkey = stm32_hash_setkey,
.halg = {
.digestsize = MD5_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "hmac(md5)",
.cra_driver_name = "stm32-hmac-md5",
@@ -1301,7 +1253,7 @@ static struct ahash_alg algs_sha1[] = {
.import = stm32_hash_import,
.halg = {
.digestsize = SHA1_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "sha1",
.cra_driver_name = "stm32-sha1",
@@ -1328,7 +1280,7 @@ static struct ahash_alg algs_sha1[] = {
.setkey = stm32_hash_setkey,
.halg = {
.digestsize = SHA1_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "hmac(sha1)",
.cra_driver_name = "stm32-hmac-sha1",
@@ -1357,7 +1309,7 @@ static struct ahash_alg algs_sha224[] = {
.import = stm32_hash_import,
.halg = {
.digestsize = SHA224_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "sha224",
.cra_driver_name = "stm32-sha224",
@@ -1384,7 +1336,7 @@ static struct ahash_alg algs_sha224[] = {
.import = stm32_hash_import,
.halg = {
.digestsize = SHA224_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "hmac(sha224)",
.cra_driver_name = "stm32-hmac-sha224",
@@ -1413,7 +1365,7 @@ static struct ahash_alg algs_sha256[] = {
.import = stm32_hash_import,
.halg = {
.digestsize = SHA256_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "sha256",
.cra_driver_name = "stm32-sha256",
@@ -1440,7 +1392,7 @@ static struct ahash_alg algs_sha256[] = {
.setkey = stm32_hash_setkey,
.halg = {
.digestsize = SHA256_DIGEST_SIZE,
- .statesize = sizeof(struct stm32_hash_request_ctx),
+ .statesize = sizeof(struct stm32_hash_state),
.base = {
.cra_name = "hmac(sha256)",
.cra_driver_name = "stm32-hmac-sha256",

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