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Merged
toddouska merged 4 commits into from
Apr 30, 2020
Merged

check on tag length for AES-CCM #2930

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231c488
check on tag length for AES-CCM
JacobBarthelmeh Apr 20, 2020
c85a53c
add macro guard for fips and selftest builds
JacobBarthelmeh Apr 27, 2020
b73e52f
move AES-CCM tag check into a local function
JacobBarthelmeh Apr 28, 2020
505fbed
fix AES-CCM tag size check on decryption
JacobBarthelmeh Apr 29, 2020
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29 changes: 29 additions & 0 deletions wolfcrypt/src/aes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6970,6 +6970,21 @@ int wc_AesCcmSetKey(Aes* aes, const byte* key, word32 keySz)
return wc_AesSetKey(aes, key, keySz, NULL, AES_ENCRYPTION);
}


/* Checks if the tag size is an accepted value based on RFC 3610 section 2
* returns 0 if tag size is ok
*/
int wc_AesCcmCheckTagSize(int sz)
{
/* values here are from RFC 3610 section 2 */
if (sz != 4 && sz != 6 && sz != 8 && sz != 10 && sz != 12 && sz != 14
&& sz != 16) {
WOLFSSL_MSG("Bad auth tag size AES-CCM");
return BAD_FUNC_ARG;
}
return 0;
}

#ifdef WOLFSSL_ARMASM
/* implementation located in wolfcrypt/src/port/arm/armv8-aes.c */

Expand All @@ -6996,6 +7011,10 @@ int wc_AesCcmEncrypt(Aes* aes, byte* out, const byte* in, word32 inSz,
|| authTag == NULL || nonceSz < 7 || nonceSz > 13)
return BAD_FUNC_ARG;

if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

key = (byte*)aes->key;

status = wc_AesGetKeySize(aes, &keySize);
Expand Down Expand Up @@ -7184,6 +7203,11 @@ int wc_AesCcmEncrypt(Aes* aes, byte* out, const byte* in, word32 inSz,
authTagSz > AES_BLOCK_SIZE)
return BAD_FUNC_ARG;

/* sanity check on tag size */
if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

XMEMSET(A, 0, sizeof(A));
XMEMCPY(B+1, nonce, nonceSz);
lenSz = AES_BLOCK_SIZE - 1 - (byte)nonceSz;
Expand Down Expand Up @@ -7280,6 +7304,11 @@ int wc_AesCcmDecrypt(Aes* aes, byte* out, const byte* in, word32 inSz,
authTagSz > AES_BLOCK_SIZE)
return BAD_FUNC_ARG;

/* sanity check on tag size */
if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

o = out;
oSz = inSz;
XMEMCPY(B+1, nonce, nonceSz);
Expand Down
8 changes: 8 additions & 0 deletions wolfcrypt/src/port/arm/armv8-aes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4438,6 +4438,10 @@ int wc_AesCcmEncrypt(Aes* aes, byte* out, const byte* in, word32 inSz,
|| authTag == NULL || nonceSz < 7 || nonceSz > 13)
return BAD_FUNC_ARG;

if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

XMEMCPY(B+1, nonce, nonceSz);
lenSz = AES_BLOCK_SIZE - 1 - (byte)nonceSz;
B[0] = (authInSz > 0 ? 64 : 0)
Expand Down Expand Up @@ -4506,6 +4510,10 @@ int wc_AesCcmDecrypt(Aes* aes, byte* out, const byte* in, word32 inSz,
|| authTag == NULL || nonceSz < 7 || nonceSz > 13)
return BAD_FUNC_ARG;

if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

o = out;
oSz = inSz;
XMEMCPY(B+1, nonce, nonceSz);
Expand Down
8 changes: 8 additions & 0 deletions wolfcrypt/src/port/caam/caam_aes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -497,6 +497,10 @@ int wc_AesCcmEncrypt(Aes* aes, byte* out,
authTagSz > AES_BLOCK_SIZE)
return BAD_FUNC_ARG;

if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

if (wc_AesGetKeySize(aes, &keySz) != 0) {
return BAD_FUNC_ARG;
}
Expand Down Expand Up @@ -576,6 +580,10 @@ int wc_AesCcmDecrypt(Aes* aes, byte* out,
authTagSz > AES_BLOCK_SIZE)
return BAD_FUNC_ARG;

if (wc_AesCcmCheckTagSize(authTagSz) != 0) {
return BAD_FUNC_ARG;
}

if (wc_AesGetKeySize(aes, &keySz) != 0) {
return BAD_FUNC_ARG;
}
Expand Down
14 changes: 14 additions & 0 deletions wolfcrypt/test/test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9157,6 +9157,20 @@ int aesccm_test(void)
return -6313;
#endif

#if !defined(HAVE_FIPS) && !defined(HAVE_SELFTEST)
/* test fail on invalid IV sizes */
result = wc_AesCcmSetKey(&enc, k, sizeof(k));
if (result != 0)
return -6314;

/* AES-CCM encrypt and decrypt both use AES encrypt internally */
result = wc_AesCcmEncrypt(&enc, c2, p, sizeof(c2), iv, sizeof(iv),
t2, 1, a, sizeof(a));
if (result == 0) {
return -6315;
}
#endif

return 0;
}
#endif /* HAVE_AESCCM WOLFSSL_AES_128 */
Expand Down
1 change: 1 addition & 0 deletions wolfssl/wolfcrypt/aes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -369,6 +369,7 @@ WOLFSSL_API int wc_AesEcbDecrypt(Aes* aes, byte* out,
word32 cSz, byte* s, word32 sSz);
#endif /* HAVE_AESGCM */
#ifdef HAVE_AESCCM
WOLFSSL_LOCAL int wc_AesCcmCheckTagSize(int sz);
WOLFSSL_API int wc_AesCcmSetKey(Aes* aes, const byte* key, word32 keySz);
WOLFSSL_API int wc_AesCcmEncrypt(Aes* aes, byte* out,
const byte* in, word32 inSz,
Expand Down