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Fix Blake2 oversized key path #10447

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Merged
SparkiDev merged 1 commit into from
May 12, 2026
Merged

Fix Blake2 oversized key path #10447

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18 changes: 9 additions & 9 deletions wolfcrypt/src/blake2b.c
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Original file line number Diff line number Diff line change
Expand Up @@ -501,6 +501,8 @@ int wc_Blake2bHmacInit(Blake2b* b2b, const byte* key, size_t key_len)
if (key == NULL)
return BAD_FUNC_ARG;

XMEMSET(x_key, 0, sizeof(x_key));

if (key_len > BLAKE2B_BLOCKBYTES) {
ret = wc_InitBlake2b(b2b, BLAKE2B_OUTBYTES);
if (ret == 0)
Expand All @@ -509,9 +511,6 @@ int wc_Blake2bHmacInit(Blake2b* b2b, const byte* key, size_t key_len)
ret = wc_Blake2bFinal(b2b, x_key, 0);
} else {
XMEMCPY(x_key, key, key_len);
if (key_len < BLAKE2B_BLOCKBYTES) {
XMEMSET(x_key + key_len, 0, BLAKE2B_BLOCKBYTES - key_len);
}
}

if (ret == 0) {
Expand Down Expand Up @@ -541,6 +540,7 @@ int wc_Blake2bHmacFinal(Blake2b* b2b, const byte* key, size_t key_len,
byte* out, size_t out_len)
{
byte x_key[BLAKE2B_BLOCKBYTES];
Blake2b keyHash;
int i;
int ret = 0;

Expand All @@ -550,17 +550,17 @@ int wc_Blake2bHmacFinal(Blake2b* b2b, const byte* key, size_t key_len,
if (out_len != BLAKE2B_OUTBYTES)
return BUFFER_E;

XMEMSET(x_key, 0, sizeof(x_key));

if (key_len > BLAKE2B_BLOCKBYTES) {
ret = wc_InitBlake2b(b2b, BLAKE2B_OUTBYTES);
ret = wc_InitBlake2b(&keyHash, BLAKE2B_OUTBYTES);
if (ret == 0)
ret = wc_Blake2bUpdate(b2b, key, (word32)key_len);
ret = wc_Blake2bUpdate(&keyHash, key, (word32)key_len);
if (ret == 0)
ret = wc_Blake2bFinal(b2b, x_key, 0);
ret = wc_Blake2bFinal(&keyHash, x_key, 0);
ForceZero(&keyHash, sizeof(keyHash));
} else {
XMEMCPY(x_key, key, key_len);
if (key_len < BLAKE2B_BLOCKBYTES) {
XMEMSET(x_key + key_len, 0, BLAKE2B_BLOCKBYTES - key_len);
}
}

if (ret == 0) {
Expand Down
18 changes: 9 additions & 9 deletions wolfcrypt/src/blake2s.c
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Original file line number Diff line number Diff line change
Expand Up @@ -498,6 +498,8 @@ int wc_Blake2sHmacInit(Blake2s* b2s, const byte* key, size_t key_len)
if (key == NULL)
return BAD_FUNC_ARG;

XMEMSET(x_key, 0, sizeof(x_key));

if (key_len > BLAKE2S_BLOCKBYTES) {
ret = wc_InitBlake2s(b2s, BLAKE2S_OUTBYTES);
if (ret == 0)
Expand All @@ -506,9 +508,6 @@ int wc_Blake2sHmacInit(Blake2s* b2s, const byte* key, size_t key_len)
ret = wc_Blake2sFinal(b2s, x_key, 0);
} else {
XMEMCPY(x_key, key, key_len);
if (key_len < BLAKE2S_BLOCKBYTES) {
XMEMSET(x_key + key_len, 0, BLAKE2S_BLOCKBYTES - key_len);
}
}

if (ret == 0) {
Expand Down Expand Up @@ -538,6 +537,7 @@ int wc_Blake2sHmacFinal(Blake2s* b2s, const byte* key, size_t key_len,
byte* out, size_t out_len)
{
byte x_key[BLAKE2S_BLOCKBYTES];
Blake2s keyHash;
int i;
int ret = 0;

Expand All @@ -547,17 +547,17 @@ int wc_Blake2sHmacFinal(Blake2s* b2s, const byte* key, size_t key_len,
if (out_len != BLAKE2S_OUTBYTES)
return BUFFER_E;

XMEMSET(x_key, 0, sizeof(x_key));

if (key_len > BLAKE2S_BLOCKBYTES) {
ret = wc_InitBlake2s(b2s, BLAKE2S_OUTBYTES);
ret = wc_InitBlake2s(&keyHash, BLAKE2S_OUTBYTES);
if (ret == 0)
ret = wc_Blake2sUpdate(b2s, key, (word32)key_len);
ret = wc_Blake2sUpdate(&keyHash, key, (word32)key_len);
if (ret == 0)
ret = wc_Blake2sFinal(b2s, x_key, 0);
ret = wc_Blake2sFinal(&keyHash, x_key, 0);
ForceZero(&keyHash, sizeof(keyHash));
} else {
XMEMCPY(x_key, key, key_len);
if (key_len < BLAKE2S_BLOCKBYTES) {
XMEMSET(x_key + key_len, 0, BLAKE2S_BLOCKBYTES - key_len);
}
}

if (ret == 0) {
Expand Down
46 changes: 46 additions & 0 deletions wolfcrypt/test/test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5188,6 +5188,31 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t blake2b_hmac_test(void)
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);

{
byte long_key[BLAKE2B_BLOCKBYTES + 72];
static const byte expected_long[] = {
0xb5, 0x17, 0xd2, 0x26, 0xcb, 0x6c, 0xa2, 0x09,
0xd2, 0x56, 0x30, 0xa2, 0x55, 0xe9, 0xfa, 0xfb,
0x1e, 0x0f, 0xbf, 0x60, 0x00, 0xbd, 0x44, 0x09,
0xb7, 0xf6, 0x25, 0x75, 0x90, 0x80, 0xb1, 0xde,
0x72, 0xa5, 0x8a, 0x15, 0x95, 0xd2, 0x49, 0x8d,
0x4c, 0xdc, 0xc8, 0x68, 0x68, 0xa5, 0x07, 0x62,
0x10, 0x64, 0x0b, 0x20, 0x0b, 0xe0, 0xb0, 0xb2,
0x13, 0xf4, 0x2d, 0x42, 0x15, 0x7a, 0x5c, 0xd6,
};
int i;

for (i = 0; i < (int)sizeof(long_key); ++i)
long_key[i] = (byte)i;

ret = wc_Blake2bHmac(message2, sizeof(message2),
long_key, sizeof(long_key), out, sizeof(out));
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);
if (XMEMCMP(out, expected_long, sizeof(out)) != 0)
return WC_TEST_RET_ENC_NC;
}

return 0;
}
#endif /* HAVE_BLAKE2B */
Expand Down Expand Up @@ -5326,6 +5351,27 @@ WOLFSSL_TEST_SUBROUTINE wc_test_ret_t blake2s_hmac_test(void)
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);

{
byte long_key[BLAKE2S_BLOCKBYTES + 36];
static const byte expected_long[] = {
0x1a, 0xd0, 0x73, 0xd7, 0xba, 0xab, 0x55, 0x83,
0x26, 0xa8, 0xc2, 0x71, 0xf2, 0x1a, 0xdf, 0x3e,
0x28, 0x57, 0x14, 0x49, 0x3a, 0x26, 0x33, 0xe7,
0x7f, 0xf4, 0xca, 0x1a, 0xfd, 0xa3, 0xe0, 0xd9,
};
int i;

for (i = 0; i < (int)sizeof(long_key); ++i)
long_key[i] = (byte)i;

ret = wc_Blake2sHmac(message2, sizeof(message2),
long_key, sizeof(long_key), out, sizeof(out));
if (ret != 0)
return WC_TEST_RET_ENC_EC(ret);
if (XMEMCMP(out, expected_long, sizeof(out)) != 0)
return WC_TEST_RET_ENC_NC;
}

return 0;
}
#endif /* HAVE_BLAKE2S */
Expand Down
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