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Fix PEM input validation and zeroize sensitive key buffers #10231

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Merged
SparkiDev merged 3 commits into from
Apr 17, 2026
+36 −3
Merged

Fix PEM input validation and zeroize sensitive key buffers #10231

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bdebcfc
reject negative pemSz in PEM-to-DER APIs
JeremiahM37 Apr 15, 2026
897ce55
zero HMAC-DRBG K and V in deterministic k
JeremiahM37 Apr 15, 2026
e182645
zero PKCS12 key bag buffers before free
JeremiahM37 Apr 15, 2026
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14 changes: 14 additions & 0 deletions tests/api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11869,6 +11869,10 @@ static int test_wc_CertPemToDer(void)
(int)cert_dersz, CERT_TYPE), WC_NO_ERR_TRACE(BAD_FUNC_ARG));
ExpectIntEQ(wc_CertPemToDer(cert_buf, (int)cert_sz, cert_der, -1,
CERT_TYPE), WC_NO_ERR_TRACE(BAD_FUNC_ARG));
ExpectIntEQ(wc_CertPemToDer(cert_buf, -1, cert_der, (int)cert_dersz,
CERT_TYPE), WC_NO_ERR_TRACE(BAD_FUNC_ARG));
ExpectIntEQ(wc_CertPemToDer(cert_buf, 0, cert_der, (int)cert_dersz,
CERT_TYPE), WC_NO_ERR_TRACE(BAD_FUNC_ARG));

if (cert_der != NULL)
free(cert_der);
Expand Down Expand Up @@ -11925,6 +11929,12 @@ static int test_wc_KeyPemToDer(void)
ExpectIntEQ(wc_KeyPemToDer(cert_buf, cert_sz, (byte*)&cert_der, 0, ""),
WC_NO_ERR_TRACE(BAD_FUNC_ARG));

/* Bad arg: negative or zero pemSz */
ExpectIntEQ(wc_KeyPemToDer(cert_buf, -1, (byte*)&cert_der, cert_sz, ""),
WC_NO_ERR_TRACE(BAD_FUNC_ARG));
ExpectIntEQ(wc_KeyPemToDer(cert_buf, 0, (byte*)&cert_der, cert_sz, ""),
WC_NO_ERR_TRACE(BAD_FUNC_ARG));

/* Test normal operation */
cert_dersz = cert_sz; /* DER will be smaller than PEM */
ExpectNotNull(cert_der = (byte*)malloc((size_t)cert_dersz));
Expand Down Expand Up @@ -11968,6 +11978,10 @@ static int test_wc_PubKeyPemToDer(void)
ExpectIntEQ(load_file(key, &cert_buf, &cert_sz), 0);
cert_dersz = cert_sz; /* DER will be smaller than PEM */
ExpectNotNull(cert_der = (byte*)malloc(cert_dersz));
ExpectIntEQ(wc_PubKeyPemToDer(cert_buf, -1, cert_der, (int)cert_dersz),
WC_NO_ERR_TRACE(BAD_FUNC_ARG));
ExpectIntEQ(wc_PubKeyPemToDer(cert_buf, 0, cert_der, (int)cert_dersz),
WC_NO_ERR_TRACE(BAD_FUNC_ARG));
ExpectIntGE(wc_PubKeyPemToDer(cert_buf, (int)cert_sz, cert_der,
(int)cert_dersz), 0);
if (cert_der != NULL) {
Expand Down
6 changes: 3 additions & 3 deletions wolfcrypt/src/asn.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24322,7 +24322,7 @@ int wc_KeyPemToDer(const unsigned char* pem, int pemSz,

WOLFSSL_ENTER("wc_KeyPemToDer");

if (pem == NULL || (buff != NULL && buffSz <= 0)) {
if (pem == NULL || (buff != NULL && buffSz <= 0) || pemSz <= 0) {
WOLFSSL_MSG("Bad pem der args");
return BAD_FUNC_ARG;
}
Expand Down Expand Up @@ -24373,7 +24373,7 @@ int wc_CertPemToDer(const unsigned char* pem, int pemSz,

WOLFSSL_ENTER("wc_CertPemToDer");

if (pem == NULL || buff == NULL || buffSz <= 0) {
if (pem == NULL || buff == NULL || buffSz <= 0 || pemSz <= 0) {
WOLFSSL_MSG("Bad pem der args");
return BAD_FUNC_ARG;
}
Expand Down Expand Up @@ -24420,7 +24420,7 @@ int wc_PubKeyPemToDer(const unsigned char* pem, int pemSz,

WOLFSSL_ENTER("wc_PubKeyPemToDer");

if (pem == NULL || (buff != NULL && buffSz <= 0)) {
if (pem == NULL || (buff != NULL && buffSz <= 0) || pemSz <= 0) {
WOLFSSL_MSG("Bad pem der args");
return BAD_FUNC_ARG;
}
Expand Down
9 changes: 9 additions & 0 deletions wolfcrypt/src/ecc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7666,6 +7666,11 @@ int wc_ecc_gen_deterministic_k(const byte* hash, word32 hashSz,
/* 3.2 c. Set K = 0x00 0x00 ... */
XMEMSET(K, 0x00, KSz);

#ifdef WOLFSSL_CHECK_MEM_ZERO
wc_MemZero_Add("wc_ecc_gen_deterministic_k K", K, KSz);
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JeremiahM37 marked this conversation as resolved.
wc_MemZero_Add("wc_ecc_gen_deterministic_k V", V, VSz);
#endif

if (ret == 0) {
ret = mp_init(z1); /* always init z1 and free z1 */
}
Expand Down Expand Up @@ -7808,6 +7813,8 @@ int wc_ecc_gen_deterministic_k(const byte* hash, word32 hashSz,
}

ForceZero(x, MAX_ECC_BYTES);
ForceZero(K, WC_MAX_DIGEST_SIZE);
ForceZero(V, WC_MAX_DIGEST_SIZE);
#ifdef WOLFSSL_SMALL_STACK
XFREE(z1, heap, DYNAMIC_TYPE_ECC_BUFFER);
XFREE(x, heap, DYNAMIC_TYPE_PRIVATE_KEY);
Expand All @@ -7816,6 +7823,8 @@ int wc_ecc_gen_deterministic_k(const byte* hash, word32 hashSz,
XFREE(h1, heap, DYNAMIC_TYPE_DIGEST);
#elif defined(WOLFSSL_CHECK_MEM_ZERO)
wc_MemZero_Check(x, MAX_ECC_BYTES);
wc_MemZero_Check(K, WC_MAX_DIGEST_SIZE);
wc_MemZero_Check(V, WC_MAX_DIGEST_SIZE);
#endif

return ret;
Expand Down
10 changes: 10 additions & 0 deletions wolfcrypt/src/pkcs12.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1976,6 +1976,7 @@ static int wc_PKCS12_create_key_bag(WC_PKCS12* pkcs12, WC_RNG* rng,
word32 sz;
word32 i;
word32 tmpSz;
word32 tmpAllocSz;
int ret;

/* get max size for shrouded key */
Expand Down Expand Up @@ -2014,6 +2015,7 @@ static int wc_PKCS12_create_key_bag(WC_PKCS12* pkcs12, WC_RNG* rng,
}

/* shroud key */
tmpAllocSz = length;
tmp = (byte*)XMALLOC(length, heap, DYNAMIC_TYPE_TMP_BUFFER);
if (tmp == NULL) {
return MEMORY_E;
Expand All @@ -2022,11 +2024,13 @@ static int wc_PKCS12_create_key_bag(WC_PKCS12* pkcs12, WC_RNG* rng,
ret = wc_PKCS12_shroud_key(pkcs12, rng, tmp, &length, key, keySz,
algo, pass, passSz, iter);
if (ret < 0) {
ForceZero(tmp, tmpAllocSz);
XFREE(tmp, heap, DYNAMIC_TYPE_TMP_BUFFER);
return ret;
}
length = (word32)ret;
XMEMCPY(out + idx, tmp, (size_t)length);
ForceZero(tmp, tmpAllocSz);
XFREE(tmp, heap, DYNAMIC_TYPE_TMP_BUFFER);
totalSz += length;

Expand Down Expand Up @@ -2357,6 +2361,7 @@ static byte* PKCS12_create_key_content(WC_PKCS12* pkcs12, int nidKey,
{
byte* keyBuf;
word32 keyBufSz = 0;
word32 keyBufAllocSz = 0;
byte* keyCi = NULL;
word32 tmpSz;
int ret;
Expand Down Expand Up @@ -2406,6 +2411,7 @@ static byte* PKCS12_create_key_content(WC_PKCS12* pkcs12, int nidKey,

/* account for sequence around bag */
keyBufSz += MAX_SEQ_SZ;
keyBufAllocSz = keyBufSz;
keyBuf = (byte*)XMALLOC(keyBufSz, heap, DYNAMIC_TYPE_TMP_BUFFER);
if (keyBuf == NULL) {
WOLFSSL_MSG("Memory error creating keyBuf buffer");
Expand All @@ -2415,6 +2421,7 @@ static byte* PKCS12_create_key_content(WC_PKCS12* pkcs12, int nidKey,
ret = wc_PKCS12_create_key_bag(pkcs12, rng, keyBuf + MAX_SEQ_SZ, &keyBufSz,
key, keySz, algo, iter, pass, (int)passSz);
if (ret < 0) {
ForceZero(keyBuf, keyBufAllocSz);
XFREE(keyBuf, heap, DYNAMIC_TYPE_TMP_BUFFER);
WOLFSSL_MSG("Error creating key bag");
return NULL;
Expand All @@ -2437,18 +2444,21 @@ static byte* PKCS12_create_key_content(WC_PKCS12* pkcs12, int nidKey,
ret = wc_PKCS12_encrypt_content(pkcs12, rng, NULL, keyCiSz,
NULL, keyBufSz, algo, pass, (int)passSz, iter, WC_PKCS12_DATA);
if (ret != WC_NO_ERR_TRACE(LENGTH_ONLY_E)) {
ForceZero(keyBuf, keyBufAllocSz);
XFREE(keyBuf, heap, DYNAMIC_TYPE_TMP_BUFFER);
WOLFSSL_MSG("Error getting key encrypt content size");
return NULL;
}
keyCi = (byte*)XMALLOC(*keyCiSz, heap, DYNAMIC_TYPE_TMP_BUFFER);
if (keyCi == NULL) {
ForceZero(keyBuf, keyBufAllocSz);
XFREE(keyBuf, heap, DYNAMIC_TYPE_TMP_BUFFER);
return NULL;
}

ret = wc_PKCS12_encrypt_content(pkcs12, rng, keyCi, keyCiSz,
keyBuf, keyBufSz, algo, pass, (int)passSz, iter, WC_PKCS12_DATA);
ForceZero(keyBuf, keyBufAllocSz);
XFREE(keyBuf, heap, DYNAMIC_TYPE_TMP_BUFFER);
if (ret < 0 ) {
XFREE(keyCi, heap, DYNAMIC_TYPE_TMP_BUFFER);
Expand Down
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