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wolfcrypt/src/wc_xmss_impl.c: guided by clang-tidy 20.0.0_pre20250104…
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…, add some error-checking to wc_xmss_bds_state_load() and wc_xmss_bds_state_store(), but ultimately, suppress a pair of stubborn apparently-false "function call argument is an uninitialized value" warnings, one in wc_xmss_bds_state_store() and one in wc_xmss_sign().
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@douzzer
douzzer committed Jan 7, 2025
1 parent 78c4a04 commit 8c32238
Showing 1 changed file with 32 additions and 18 deletions.
50 changes: 32 additions & 18 deletions wolfcrypt/src/wc_xmss_impl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2675,7 +2675,7 @@ static void wc_xmss_bds_state_free(BdsState* bds)
* @param [out] bds BDS states.
* @param [out] wots_sigs WOTS signatures when XMSS^MT.
*/
static void wc_xmss_bds_state_load(const XmssState* state, byte* sk,
static int wc_xmss_bds_state_load(const XmssState* state, byte* sk,
BdsState* bds, byte** wots_sigs)
{
const XmssParams* params = state->params;
Expand All @@ -2689,6 +2689,9 @@ static void wc_xmss_bds_state_load(const XmssState* state, byte* sk,
/* Skip past standard SK = idx || wots_sk || SK_PRF || root || SEED; */
sk += params->idx_len + 4 * n;

if (2 * (int)params->d - 1 < 0)
return WC_FAILURE;

for (i = 0; i < 2 * (int)params->d - 1; i++) {
/* Set pointers into SK. */
bds[i].stack = sk;
Expand All @@ -2715,6 +2718,8 @@ static void wc_xmss_bds_state_load(const XmssState* state, byte* sk,
if (wots_sigs != NULL) {
*wots_sigs = sk;
}

return 0;
}

/* Store the BDS state into the secret/private key.
Expand All @@ -2723,7 +2728,7 @@ static void wc_xmss_bds_state_load(const XmssState* state, byte* sk,
* @param [in, out] sk Secret/private key.
* @param [in] bds BDS states.
*/
static void wc_xmss_bds_state_store(const XmssState* state, byte* sk,
static int wc_xmss_bds_state_store(const XmssState* state, byte* sk,
BdsState* bds)
{
int i;
Expand All @@ -2743,15 +2748,20 @@ static void wc_xmss_bds_state_store(const XmssState* state, byte* sk,
/* Ignore standard SK = idx || wots_sk || SK_PRF || root || SEED; */
sk += params->idx_len + 4 * n;

if (2 * (int)params->d - 1 < 0)
return WC_FAILURE;

for (i = 0; i < 2 * (int)params->d - 1; i++) {
/* Skip pointers into sk. */
sk += skip;
/* Save values - big-endian encoded. */
c32to24(bds[i].next, sk);
c32to24(bds[i].next, sk); /* NOLINT(clang-analyzer-core.CallAndMessage) */
sk += 3;
sk[0] = bds[i].offset;
sk += 1;
}

return 0;
}

/********************************************
Expand Down Expand Up @@ -3297,6 +3307,10 @@ int wc_xmss_keygen(XmssState* state, const unsigned char* seed,
if (ret == 0)
#endif
{
/* Setup pointers into sk - assumes sk is initialized to zeros. */
ret = wc_xmss_bds_state_load(state, sk, bds, NULL);
}
if (ret == 0) {
/* Offsets into seed. */
const byte* seed_priv = seed;
const byte* seed_pub = seed + 2 * n;
Expand All @@ -3306,9 +3320,6 @@ int wc_xmss_keygen(XmssState* state, const unsigned char* seed,
/* Offsets into public key. */
byte* pk_seed = pk + n;

/* Setup pointers into sk - assumes sk is initialized to zeros. */
wc_xmss_bds_state_load(state, sk, bds, NULL);

/* Set first index to 0 in private key. idx_len always 4. */
*sk_idx = 0;
/* Set private key seed and private key for PRF in to private key. */
Expand All @@ -3333,7 +3344,7 @@ int wc_xmss_keygen(XmssState* state, const unsigned char* seed,
XMEMCPY(sk_root, pk_root, 2 * n);

/* Store BDS state back into secret/private key. */
wc_xmss_bds_state_store(state, sk, bds);
ret = wc_xmss_bds_state_store(state, sk, bds);
}

#ifdef WOLFSSL_SMALL_STACK
Expand Down Expand Up @@ -3412,8 +3423,9 @@ int wc_xmss_sign(XmssState* state, const unsigned char* m, word32 mlen,
#endif
{
/* Load the BDS state from secret/private key. */
wc_xmss_bds_state_load(state, sk, bds, NULL);

ret = wc_xmss_bds_state_load(state, sk, bds, NULL);
}
if (ret == 0) {
/* Copy the index into the signature data: Sig = idx_sig || ... */
*((word32*)sig) = *((word32*)sk);
/* Read index from the secret key. */
Expand Down Expand Up @@ -3468,7 +3480,7 @@ int wc_xmss_sign(XmssState* state, const unsigned char* m, word32 mlen,
if (ret == 0) {
sig += params->wots_sig_len;
/* Add authentication path (auth) and calc new root. */
XMEMCPY(sig, bds->authPath, h * n);
XMEMCPY(sig, bds->authPath, h * n); /* NOLINT(clang-analyzer-core.CallAndMessage) */
ret = state->ret;
}

Expand All @@ -3490,7 +3502,7 @@ int wc_xmss_sign(XmssState* state, const unsigned char* m, word32 mlen,
}
if (ret == 0) {
/* Store BDS state back into secret/private key. */
wc_xmss_bds_state_store(state, sk, bds);
ret = wc_xmss_bds_state_store(state, sk, bds);
}

#ifdef WOLFSSL_SMALL_STACK
Expand Down Expand Up @@ -3580,14 +3592,15 @@ int wc_xmssmt_keygen(XmssState* state, const unsigned char* seed,

/* Allocate memory for BDS states and tree hash instances. */
ret = wc_xmss_bds_state_alloc(params, &bds);
if (ret == 0) {
/* Load the BDS state from secret/private key. */
ret = wc_xmss_bds_state_load(state, sk, bds, &wots_sigs);
}
if (ret == 0) {
/* Offsets into seed. */
const byte* seed_priv = seed;
const byte* seed_pub = seed + 2 * params->n;

/* Load the BDS state from secret/private key. */
wc_xmss_bds_state_load(state, sk, bds, &wots_sigs);

/* Set first index to 0 in private key. */
XMEMSET(sk, 0, params->idx_len);
/* Set private key seed and private key for PRF in to private key. */
Expand Down Expand Up @@ -3630,7 +3643,7 @@ int wc_xmssmt_keygen(XmssState* state, const unsigned char* seed,
XMEMCPY(sk_root, pk_root, 2 * n);

/* Store BDS state back into secret/private key. */
wc_xmss_bds_state_store(state, sk, bds);
ret = wc_xmss_bds_state_store(state, sk, bds);
}

/* Dispose of allocated data of BDS states. */
Expand Down Expand Up @@ -4000,8 +4013,9 @@ int wc_xmssmt_sign(XmssState* state, const unsigned char* m, word32 mlen,
ret = wc_xmss_bds_state_alloc(params, &bds);
if (ret == 0) {
/* Load the BDS state from secret/private key. */
wc_xmss_bds_state_load(state, sk, bds, &wots_sigs);

ret = wc_xmss_bds_state_load(state, sk, bds, &wots_sigs);
}
if (ret == 0) {
/* Copy the index into the signature data: Sig_MT = idx_sig. */
XMEMCPY(sig_mt, sk, idx_len);

Expand Down Expand Up @@ -4032,7 +4046,7 @@ int wc_xmssmt_sign(XmssState* state, const unsigned char* m, word32 mlen,

if (ret == 0) {
/* Store BDS state back into secret/private key. */
wc_xmss_bds_state_store(state, sk, bds);
ret = wc_xmss_bds_state_store(state, sk, bds);
}

/* Dispose of allocated data of BDS states. */
Expand Down

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