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Fix to resolve STM32 hash FIFO. Simplify logic for ensuring FIFO gets filled before doing a save/restore. ZD 18294

pull/7787/head
David Garske 2024-07-24 16:06:04 -07:00
parent 6a26569ddc
commit 42403a526e
3 changed files with 17 additions and 52 deletions
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41
wolfcrypt/src/port/st/stm32.c
View File

@ -303,12 +303,11 @@ int wc_Stm32_Hash_Update(STM32_HASH_Context* stmCtx, word32 algo,
int ret = 0;
byte* local = (byte*)stmCtx->buffer;
int wroteToFifo = 0;
const word32 fifoSz = (STM32_HASH_FIFO_SIZE * STM32_HASH_REG_SIZE);
word32 chunkSz;
#ifdef DEBUG_STM32_HASH
printf("STM Hash Update: algo %x, len %d, blockSz %d\n",
algo, len, blockSize);
printf("STM Hash Update: algo %x, len %d, buffLen %d, fifoBytes %d\n",
algo, len, stmCtx->buffLen, stmCtx->fifoBytes);
#endif
(void)blockSize;
@ -323,40 +322,27 @@ 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 add = min(len, chunkSz - stmCtx->buffLen);
word32 add;
/* fill the FIFO plus one additional to flush the block */
chunkSz = ((STM32_HASH_FIFO_SIZE + 1) * STM32_HASH_REG_SIZE);
/* account for extra bytes in the FIFO (use mask 0x3F to get remain) */
chunkSz -= (stmCtx->fifoBytes &
((STM32_HASH_FIFO_SIZE * STM32_HASH_REG_SIZE)-1));
add = min(len, chunkSz - stmCtx->buffLen);
XMEMCPY(&local[stmCtx->buffLen], data, add);
stmCtx->buffLen += add;
data += add;
len -= add;
#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 (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
stmCtx->fifoBytes += chunkSz;
}
}
@ -380,7 +366,8 @@ int wc_Stm32_Hash_Final(STM32_HASH_Context* stmCtx, word32 algo,
int ret = 0;
#ifdef DEBUG_STM32_HASH
printf("STM Hash Final: algo %x, digestSz %d\n", algo, digestSize);
printf("STM Hash Final: algo %x, digestSz %d, buffLen %d, fifoBytes %d\n",
algo, digestSize, stmCtx->buffLen, stmCtx->fifoBytes);
#endif
/* turn on hash clock */

2
wolfcrypt/src/sha256.c
View File

@ -2496,7 +2496,7 @@ int wc_Sha256GetHash(wc_Sha256* sha256, byte* hash)
ret = wc_Sha256Copy(sha256, tmpSha256);
if (ret == 0) {
ret = wc_Sha256Final(tmpSha256, hash);
wc_Sha256Free(tmpSha256); /* TODO move outside brackets? */
wc_Sha256Free(tmpSha256);
}

26
wolfssl/wolfcrypt/port/st/stm32.h
View File

@ -71,26 +71,6 @@
#define STM32_HASH_REG_SIZE 4
#define STM32_HASH_FIFO_SIZE 16 /* FIFO is 16 deep 32-bits wide */
#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 {
/* Context switching registers */
@ -100,13 +80,11 @@ typedef struct {
uint32_t HASH_CSR[HASH_CR_SIZE];
/* Hash state / buffers */
word32 buffer[STM32_HASH_BUFFER_SIZE]; /* partial word buffer */
word32 buffer[STM32_HASH_FIFO_SIZE+1]; /* 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
word32 fifoBytes; /* number of currently filled FIFO bytes */
} STM32_HASH_Context;