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Improved fix for STM32 hashing on U5

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This commit is contained in:
David Garske 2023-05-01 11:31:58 -07:00
parent 73b3f9c01a
commit 7576380635
2 changed files with 43 additions and 23 deletions
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50
wolfcrypt/src/port/st/stm32.c
View File

@ -234,7 +234,7 @@ static void wc_Stm32_Hash_Data(STM32_HASH_Context* stmCtx, word32 len)
if (len > stmCtx->buffLen)
len = stmCtx->buffLen;
/* calculate number of 32-bit blocks */
/* calculate number of 32-bit blocks - round up */
blocks = ((len + STM32_HASH_REG_SIZE-1) / STM32_HASH_REG_SIZE);
#ifdef DEBUG_STM32_HASH
printf("STM DIN %d blocks\n", blocks);
@ -268,17 +268,16 @@ int wc_Stm32_Hash_Update(STM32_HASH_Context* stmCtx, word32 algo,
byte* local = (byte*)stmCtx->buffer;
int wroteToFifo = 0;
const word32 fifoSz = (STM32_HASH_FIFO_SIZE * STM32_HASH_REG_SIZE);
if (blockSize > fifoSz)
blockSize = fifoSz;
word32 chunkSz;
#ifdef DEBUG_STM32_HASH
printf("STM Hash Update: algo %x, len %d, blockSz %d\n",
algo, len, blockSize);
#endif
(void)blockSize;
/* check that internal buffLen is valid */
if (stmCtx->buffLen > blockSize) {
if (stmCtx->buffLen > (word32)sizeof(stmCtx->buffer)) {
return BUFFER_E;
}
@ -288,37 +287,44 @@ int wc_Stm32_Hash_Update(STM32_HASH_Context* stmCtx, word32 algo,
/* restore hash context or init as new hash */
wc_Stm32_Hash_RestoreContext(stmCtx, algo);
chunkSz = fifoSz;
#ifdef STM32_HASH_FIFO_WORKAROUND
/* if FIFO already has bytes written then fill remainder first */
if (stmCtx->fifoBytes > 0) {
chunkSz -= stmCtx->fifoBytes;
stmCtx->fifoBytes = 0;
}
#endif
/* write blocks to FIFO */
while (len) {
word32 fillBlockSz = blockSize, add;
/* if FIFO already has bytes written then fill remainder first */
if (stmCtx->fifoBytes > 0) {
fillBlockSz -= stmCtx->fifoBytes;
stmCtx->fifoBytes = 0;
}
add = min(len, fillBlockSz - stmCtx->buffLen);
word32 add = min(len, chunkSz - stmCtx->buffLen);
XMEMCPY(&local[stmCtx->buffLen], data, add);
stmCtx->buffLen += add;
data += add;
len -= add;
if (len > 0 && stmCtx->buffLen == fillBlockSz) {
#ifdef STM32_HASH_FIFO_WORKAROUND
/* We cannot leave the FIFO full and do save/restore
* the last must be large enough to flush block from FIFO */
if (stmCtx->buffLen + len <= fifoSz * 2) {
chunkSz = fifoSz + STM32_HASH_REG_SIZE;
}
#endif
if (len >= 0 && stmCtx->buffLen == chunkSz) {
wc_Stm32_Hash_Data(stmCtx, stmCtx->buffLen);
wroteToFifo = 1;
#ifdef STM32_HASH_FIFO_WORKAROUND
if (chunkSz > fifoSz)
stmCtx->fifoBytes = chunkSz - fifoSz;
chunkSz = fifoSz;
#endif
}
}
if (wroteToFifo) {
#ifdef STM32_HASH_FIFO_WORKAROUND
/* If we wrote a block send one more 32-bit to FIFO to trigger start.
* The save/restore feature cannot leave 16 deep FIFO filled. */
wc_Stm32_Hash_Data(stmCtx, 4);
stmCtx->fifoBytes += 4;
#endif
/* make sure hash operation is done */
ret = wc_Stm32_Hash_WaitDone(stmCtx);

16
wolfssl/wolfcrypt/port/st/stm32.h
View File

@ -74,10 +74,22 @@
#if (defined(WOLFSSL_STM32U5) || defined(WOLFSSL_STM32H5) || \
defined(WOLFSSL_STM32H7)) && !defined(NO_STM32_HASH_FIFO_WORKAROUND)
/* workaround for hash FIFO to write one extra to finalize */
/* RM: Message Data Feeding: Data are entered into the HASH
* one 32-bit word at a time, by writing them into the HASH_DIN register.
* The current contents of the HASH_DIN register are transferred to the
* 16 words input FIFO each time the register is written with new data.
* Hence HASH_DIN and the FIFO form a seventeen 32-bit words length FIFO. */
#undef STM32_HASH_BUFFER_SIZE
#define STM32_HASH_BUFFER_SIZE 17
#undef STM32_HASH_FIFO_WORKAROUND
#define STM32_HASH_FIFO_WORKAROUND
#endif
#ifndef STM32_HASH_BUFFER_SIZE
#define STM32_HASH_BUFFER_SIZE STM32_HASH_FIFO_SIZE
#endif
/* STM32 Hash Context */
typedef struct {
@ -88,11 +100,13 @@ typedef struct {
uint32_t HASH_CSR[HASH_CR_SIZE];
/* Hash state / buffers */
word32 buffer[STM32_HASH_FIFO_SIZE]; /* partial word buffer */
word32 buffer[STM32_HASH_BUFFER_SIZE]; /* partial word buffer */
word32 buffLen; /* partial word remain */
word32 loLen; /* total update bytes
(only lsb 6-bits is used for nbr valid bytes in last word) */
#ifdef STM32_HASH_FIFO_WORKAROUND
int fifoBytes; /* number of currently filled FIFO bytes */
#endif
} STM32_HASH_Context;