Export and import interfaces save and restore partial transformation
states. The partial states were being stored and restored in struct
sha1_state for sha1/hmac(sha1) transformations and sha256_state for
sha256/hmac(sha256) transformations.This led to a bunch of corner cases
where improper state was being stored and restored. A few of the corner
cases that turned up during testing are:

- wrong byte_count restored if export/import is called twice without h/w
transaction in between
- wrong buflen restored back if the pending buffer
length is exactly the block size.
- wrong state restored if buffer length is 0.

To fix these issues, save and restore the partial transformation state
using the newly introduced qce_sha_saved_state struct. This ensures that
all the pieces required to properly restart the transformation is captured
and restored back

Signed-off-by: Thara Gopinath <thara.gopin...@linaro.org>
---

v1->v2:
        - Introduced custom struct qce_sha_saved_state to store and
          restore partial sha transformation. v1 was re-using
          qce_sha_reqctx to save and restore partial states and this
          could lead to potential memcpy issues around pointer copying.

 drivers/crypto/qce/sha.c | 122 +++++++++++----------------------------
 1 file changed, 34 insertions(+), 88 deletions(-)

diff --git a/drivers/crypto/qce/sha.c b/drivers/crypto/qce/sha.c
index 61c418c12345..08aed03e2b59 100644
--- a/drivers/crypto/qce/sha.c
+++ b/drivers/crypto/qce/sha.c
@@ -12,9 +12,15 @@
 #include "core.h"
 #include "sha.h"
 
-/* crypto hw padding constant for first operation */
-#define SHA_PADDING            64
-#define SHA_PADDING_MASK       (SHA_PADDING - 1)
+struct qce_sha_saved_state {
+       u8 pending_buf[QCE_SHA_MAX_BLOCKSIZE];
+       u8 partial_digest[QCE_SHA_MAX_DIGESTSIZE];
+       __be32 byte_count[2];
+       unsigned int pending_buflen;
+       unsigned int flags;
+       u64 count;
+       bool first_blk;
+};
 
 static LIST_HEAD(ahash_algs);
 
@@ -139,97 +145,37 @@ static int qce_ahash_init(struct ahash_request *req)
 
 static int qce_ahash_export(struct ahash_request *req, void *out)
 {
-       struct crypto_ahash *ahash = crypto_ahash_reqtfm(req);
        struct qce_sha_reqctx *rctx = ahash_request_ctx(req);
-       unsigned long flags = rctx->flags;
-       unsigned int digestsize = crypto_ahash_digestsize(ahash);
-       unsigned int blocksize =
-                       crypto_tfm_alg_blocksize(crypto_ahash_tfm(ahash));
-
-       if (IS_SHA1(flags) || IS_SHA1_HMAC(flags)) {
-               struct sha1_state *out_state = out;
-
-               out_state->count = rctx->count;
-               qce_cpu_to_be32p_array((__be32 *)out_state->state,
-                                      rctx->digest, digestsize);
-               memcpy(out_state->buffer, rctx->buf, blocksize);
-       } else if (IS_SHA256(flags) || IS_SHA256_HMAC(flags)) {
-               struct sha256_state *out_state = out;
-
-               out_state->count = rctx->count;
-               qce_cpu_to_be32p_array((__be32 *)out_state->state,
-                                      rctx->digest, digestsize);
-               memcpy(out_state->buf, rctx->buf, blocksize);
-       } else {
-               return -EINVAL;
-       }
-
-       return 0;
-}
-
-static int qce_import_common(struct ahash_request *req, u64 in_count,
-                            const u32 *state, const u8 *buffer, bool hmac)
-{
-       struct crypto_ahash *ahash = crypto_ahash_reqtfm(req);
-       struct qce_sha_reqctx *rctx = ahash_request_ctx(req);
-       unsigned int digestsize = crypto_ahash_digestsize(ahash);
-       unsigned int blocksize;
-       u64 count = in_count;
-
-       blocksize = crypto_tfm_alg_blocksize(crypto_ahash_tfm(ahash));
-       rctx->count = in_count;
-       memcpy(rctx->buf, buffer, blocksize);
-
-       if (in_count <= blocksize) {
-               rctx->first_blk = 1;
-       } else {
-               rctx->first_blk = 0;
-               /*
-                * For HMAC, there is a hardware padding done when first block
-                * is set. Therefore the byte_count must be incremened by 64
-                * after the first block operation.
-                */
-               if (hmac)
-                       count += SHA_PADDING;
-       }
+       struct qce_sha_saved_state *export_state = out;
 
-       rctx->byte_count[0] = (__force __be32)(count & ~SHA_PADDING_MASK);
-       rctx->byte_count[1] = (__force __be32)(count >> 32);
-       qce_cpu_to_be32p_array((__be32 *)rctx->digest, (const u8 *)state,
-                              digestsize);
-       rctx->buflen = (unsigned int)(in_count & (blocksize - 1));
+       memcpy(export_state->pending_buf, rctx->buf, rctx->buflen);
+       memcpy(export_state->partial_digest, rctx->digest,
+              sizeof(rctx->digest));
+       memcpy(export_state->byte_count, rctx->byte_count, 2);
+       export_state->pending_buflen = rctx->buflen;
+       export_state->count = rctx->count;
+       export_state->first_blk = rctx->first_blk;
+       export_state->flags = rctx->flags;
 
        return 0;
 }
 
 static int qce_ahash_import(struct ahash_request *req, const void *in)
 {
-       struct qce_sha_reqctx *rctx;
-       unsigned long flags;
-       bool hmac;
-       int ret;
-
-       ret = qce_ahash_init(req);
-       if (ret)
-               return ret;
-
-       rctx = ahash_request_ctx(req);
-       flags = rctx->flags;
-       hmac = IS_SHA_HMAC(flags);
-
-       if (IS_SHA1(flags) || IS_SHA1_HMAC(flags)) {
-               const struct sha1_state *state = in;
-
-               ret = qce_import_common(req, state->count, state->state,
-                                       state->buffer, hmac);
-       } else if (IS_SHA256(flags) || IS_SHA256_HMAC(flags)) {
-               const struct sha256_state *state = in;
+       struct qce_sha_reqctx *rctx = ahash_request_ctx(req);
+       struct qce_sha_saved_state *import_state = in;
 
-               ret = qce_import_common(req, state->count, state->state,
-                                       state->buf, hmac);
-       }
+       memset(rctx, 0, sizeof(*rctx));
+       rctx->count = import_state->count;
+       rctx->buflen = import_state->pending_buflen;
+       rctx->first_blk = import_state->first_blk;
+       rctx->flags = import_state->flags;
+       memcpy(rctx->buf, import_state->pending_buf, rctx->buflen);
+       memcpy(rctx->digest, import_state->partial_digest,
+              sizeof(rctx->digest));
+       memcpy(rctx->byte_count, import_state->byte_count, 2);
 
-       return ret;
+       return 0;
 }
 
 static int qce_ahash_update(struct ahash_request *req)
@@ -450,7 +396,7 @@ static const struct qce_ahash_def ahash_def[] = {
                .drv_name       = "sha1-qce",
                .digestsize     = SHA1_DIGEST_SIZE,
                .blocksize      = SHA1_BLOCK_SIZE,
-               .statesize      = sizeof(struct sha1_state),
+               .statesize      = sizeof(struct qce_sha_saved_state),
                .std_iv         = std_iv_sha1,
        },
        {
@@ -459,7 +405,7 @@ static const struct qce_ahash_def ahash_def[] = {
                .drv_name       = "sha256-qce",
                .digestsize     = SHA256_DIGEST_SIZE,
                .blocksize      = SHA256_BLOCK_SIZE,
-               .statesize      = sizeof(struct sha256_state),
+               .statesize      = sizeof(struct qce_sha_saved_state),
                .std_iv         = std_iv_sha256,
        },
        {
@@ -468,7 +414,7 @@ static const struct qce_ahash_def ahash_def[] = {
                .drv_name       = "hmac-sha1-qce",
                .digestsize     = SHA1_DIGEST_SIZE,
                .blocksize      = SHA1_BLOCK_SIZE,
-               .statesize      = sizeof(struct sha1_state),
+               .statesize      = sizeof(struct qce_sha_saved_state),
                .std_iv         = std_iv_sha1,
        },
        {
@@ -477,7 +423,7 @@ static const struct qce_ahash_def ahash_def[] = {
                .drv_name       = "hmac-sha256-qce",
                .digestsize     = SHA256_DIGEST_SIZE,
                .blocksize      = SHA256_BLOCK_SIZE,
-               .statesize      = sizeof(struct sha256_state),
+               .statesize      = sizeof(struct qce_sha_saved_state),
                .std_iv         = std_iv_sha256,
        },
 };
-- 
2.25.1

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