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mbedTLS SHA: Fix cloning of SHA-384 digests

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Hardware unit only reads 384 bits of state for SHA-384 LOAD,
which is enough for final digest but not enough if you plan to
resume digest in software.
This commit is contained in:
Angus Gratton 2016-11-25 19:07:19 +11:00
parent a902e2a9de
commit 88b264cfce
3 changed files with 12 additions and 5 deletions
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4
components/esp32/hwcrypto/sha.c
View file

@ -82,7 +82,7 @@ inline static size_t sha_engine_index(esp_sha_type type) {
}
}
/* Return state & digest length (in bytes) for a given SHA type */
/* Return digest length (in bytes) for a given SHA type */
inline static size_t sha_length(esp_sha_type type) {
switch(type) {
case SHA1:
@ -90,7 +90,7 @@ inline static size_t sha_length(esp_sha_type type) {
case SHA2_256:
return 32;
case SHA2_384:
return 64;
return 48;
case SHA2_512:
return 64;
default:

7
components/esp32/include/hwcrypto/sha.h
View file

@ -113,11 +113,14 @@ void esp_sha_block(esp_sha_type sha_type, const void *data_block, bool is_first_
* value that is read is the SHA digest (in big endian
* format). Otherwise, the value that is read is an interim SHA state.
*
* @note If sha_type is SHA2_384, only 48 bytes of state will be read.
* This is enough for the final SHA2_384 digest, but if you want the
* interim SHA-384 state (to continue digesting) then pass SHA2_512 instead.
*
* @param sha_type SHA algorithm in use.
*
* @param state Pointer to a memory buffer to hold the SHA state. Size
* is 20 bytes (SHA1), 64 bytes (SHA2_256), or 128 bytes (SHA2_384 or
* SHA2_512).
* is 20 bytes (SHA1), 32 bytes (SHA2_256), 48 bytes (SHA2_384) or 64 bytes (SHA2_512).
*
*/
void esp_sha_read_digest_state(esp_sha_type sha_type, void *digest_state);

6
components/mbedtls/port/esp_sha512.c
View file

@ -121,8 +121,12 @@ void mbedtls_sha512_clone( mbedtls_sha512_context *dst,
if (src->mode == ESP_MBEDTLS_SHA512_HARDWARE) {
/* Copy hardware digest state out to cloned state,
which will be a software digest.
Always read 512 bits of state, even for SHA-384
(SHA-384 state is identical to SHA-512, only
digest is truncated.)
*/
esp_sha_read_digest_state(sha_type(dst), dst->state);
esp_sha_read_digest_state(SHA2_512, dst->state);
dst->mode = ESP_MBEDTLS_SHA512_SOFTWARE;
}
}