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WOLFSSL_AES_CBC_LENGTH_CHECKS: add gated logic to aes.c wc_AesCbc{En,De}crypt() to return BAD_LENGTH_E when input length is not a multiple of AES_BLOCK_SIZE; add gated tests of new functionality in test_wc_AesCbcEncryptDecrypt(); fix first encrypt-decrypt-memcmp in test_wc_AesCbcEncryptDecrypt() to span all of test vector and extend test vector length to be block-multiple; add ungated logic in platform-specific wc_AesCbc{En,De}crypt() routines to return with early success when blocks == 0 (also mitigates buffer overrun on short (less-than-AES_BLOCK_SIZE) input); add BAD_LENGTH_E error code; update documentation.

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This commit is contained in:
Daniel Pouzzner
2021-03-25 17:52:01 -05:00
parent f201d65459
commit 5d9ee97530
5 changed files with 168 additions and 25 deletions
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132
wolfcrypt/src/aes.c
View File

@@ -3085,8 +3085,16 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
int wc_AesCbcEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
int ret = 0;
word32 blocks = (sz / AES_BLOCK_SIZE);
CRYP_HandleTypeDef hcryp;
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
ret = wc_Stm32_Aes_Init(aes, &hcryp);
if (ret != 0)
@@ -3135,8 +3143,16 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
int wc_AesCbcDecrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
int ret = 0;
word32 blocks = (sz / AES_BLOCK_SIZE);
CRYP_HandleTypeDef hcryp;
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
ret = wc_Stm32_Aes_Init(aes, &hcryp);
if (ret != 0)
@@ -3191,10 +3207,18 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
{
int ret;
word32 *iv;
word32 blocks = (sz / AES_BLOCK_SIZE);
CRYP_InitTypeDef cryptInit;
CRYP_KeyInitTypeDef keyInit;
CRYP_IVInitTypeDef ivInit;
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
ret = wc_Stm32_Aes_Init(aes, &cryptInit, &keyInit);
if (ret != 0)
@@ -3266,10 +3290,18 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
{
int ret;
word32 *iv;
word32 blocks = (sz / AES_BLOCK_SIZE);
CRYP_InitTypeDef cryptInit;
CRYP_KeyInitTypeDef keyInit;
CRYP_IVInitTypeDef ivInit;
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
ret = wc_Stm32_Aes_Init(aes, &cryptInit, &keyInit);
if (ret != 0)
@@ -3363,6 +3395,12 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
if ((pi == NULL) || (po == NULL))
return BAD_FUNC_ARG; /*wrong pointer*/
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
wc_LockMutex(&Mutex_AesSEC);
/* Set descriptor for SEC */
@@ -3388,16 +3426,24 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
secDesc->pointer7 = NULL;
secDesc->nextDescriptorPtr = NULL;
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
size = AES_BUFFER_SIZE;
#endif
while (sz) {
secDesc->header = descHeader;
XMEMCPY(secReg, aes->reg, AES_BLOCK_SIZE);
if ((sz % AES_BUFFER_SIZE) == sz) {
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
sz -= AES_BUFFER_SIZE;
#else
if (sz < AES_BUFFER_SIZE) {
size = sz;
sz = 0;
} else {
size = AES_BUFFER_SIZE;
sz -= AES_BUFFER_SIZE;
}
#endif
secDesc->length4 = size;
secDesc->length5 = size;
@@ -3463,6 +3509,14 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
byte *iv, *enc_key;
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
iv = (byte*)aes->reg;
enc_key = (byte*)aes->key;
@@ -3492,8 +3546,16 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
word32 keySize;
status_t status;
byte* iv, *dec_key;
word32 blocks = (sz / AES_BLOCK_SIZE);
byte temp_block[AES_BLOCK_SIZE];
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
iv = (byte*)aes->reg;
dec_key = (byte*)aes->key;
@@ -3527,9 +3589,17 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
{
int i;
int offset = 0;
word32 blocks = (sz / AES_BLOCK_SIZE);
byte *iv;
byte temp_block[AES_BLOCK_SIZE];
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
iv = (byte*)aes->reg;
@@ -3555,9 +3625,17 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
{
int i;
int offset = 0;
word32 blocks = (sz / AES_BLOCK_SIZE);
byte* iv;
byte temp_block[AES_BLOCK_SIZE];
word32 blocks = (sz / AES_BLOCK_SIZE);
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
if (blocks == 0)
return 0;
iv = (byte*)aes->reg;
@@ -3586,9 +3664,16 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
{
int ret;
if (sz == 0)
return 0;
/* hardware fails on input that is not a multiple of AES block size */
if (sz % AES_BLOCK_SIZE != 0) {
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
return BAD_LENGTH_E;
#else
return BAD_FUNC_ARG;
#endif
}
ret = wc_Pic32AesCrypt(
@@ -3609,9 +3694,16 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
int ret;
byte scratch[AES_BLOCK_SIZE];
if (sz == 0)
return 0;
/* hardware fails on input that is not a multiple of AES block size */
if (sz % AES_BLOCK_SIZE != 0) {
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
return BAD_LENGTH_E;
#else
return BAD_FUNC_ARG;
#endif
}
XMEMCPY(scratch, in + sz - AES_BLOCK_SIZE, AES_BLOCK_SIZE);
@@ -3666,7 +3758,7 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
/* Software AES - CBC Encrypt */
int wc_AesCbcEncrypt(Aes* aes, byte* out, const byte* in, word32 sz)
{
word32 blocks = (sz / AES_BLOCK_SIZE);
word32 blocks;
if (aes == NULL || out == NULL || in == NULL) {
return BAD_FUNC_ARG;
@@ -3675,6 +3767,14 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
if (sz == 0) {
return 0;
}
blocks = sz / AES_BLOCK_SIZE;
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
if (sz % AES_BLOCK_SIZE) {
return BAD_LENGTH_E;
}
#endif
#ifdef WOLFSSL_IMXRT_DCP
/* Implemented in wolfcrypt/src/port/nxp/dcp_port.c */
if (aes->keylen == 16)
@@ -3779,14 +3879,23 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
{
word32 blocks;
if (aes == NULL || out == NULL || in == NULL
|| sz % AES_BLOCK_SIZE != 0) {
if (aes == NULL || out == NULL || in == NULL) {
return BAD_FUNC_ARG;
}
if (sz == 0) {
return 0;
}
blocks = sz / AES_BLOCK_SIZE;
if (sz % AES_BLOCK_SIZE) {
#ifdef WOLFSSL_AES_CBC_LENGTH_CHECKS
return BAD_LENGTH_E;
#else
return BAD_FUNC_ARG;
#endif
}
#ifdef WOLFSSL_IMXRT_DCP
/* Implemented in wolfcrypt/src/port/nxp/dcp_port.c */
if (aes->keylen == 16)
@@ -3856,7 +3965,6 @@ int wc_AesSetIV(Aes* aes, const byte* iv)
}
#endif
blocks = sz / AES_BLOCK_SIZE;
while (blocks--) {
XMEMCPY(aes->tmp, in, AES_BLOCK_SIZE);
wc_AesDecrypt(aes, (byte*)aes->tmp, out);

3
wolfcrypt/src/error.c
View File

@@ -527,6 +527,9 @@ const char* wc_GetErrorString(int error)
case MISSING_KEY:
return "Required key not set";
case BAD_LENGTH_E:
return "Value of length parameter is invalid.";
default:
return "unknown error number";