kris/xmss-KAT-generator
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Adhere to more strict storage bounds

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Joost Rijneveld 2015-08-26 15:53:50 +02:00
parent 5d469d118f
commit a33aef699c
1 changed files with 9 additions and 6 deletions
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15
xmss_fast.c
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@ -95,11 +95,11 @@ typedef struct{
// TODO these data structures need to be non-global (especially for xmss_mt)
unsigned char STACK[(H-K-1)*N];
unsigned int STACKOFFSET = 0;
unsigned char STACKLEVELS[H];
unsigned char STACKLEVELS[H-K-1];
unsigned char AUTH[H*N];
unsigned char KEEP[H*N]; // this can be H / 2 + 1 rather than H, but that makes it more tedious to index
treehash_inst TREEHASH[H];
unsigned char KEEP[(H >> 1)*N];
treehash_inst TREEHASH[H-K];
unsigned char RETAIN[((1 << K) - K - 1) * N];
/**
@ -435,8 +435,13 @@ static void compute_authpath_wots_fast(unsigned char *root, unsigned char *authp
}
}
if (tau > 0) {
memcpy(buf, AUTH + (tau-1) * n, n);
// we need to do this before refreshing KEEP to prevent overwriting
memcpy(buf + n, KEEP + ((tau-1) >> 1) * n, n);
}
if (!((leaf_idx >> (tau + 1)) & 1) && (tau < h - 1)) {
memcpy(KEEP + tau*n, AUTH + tau*n, n);
memcpy(KEEP + (tau >> 1)*n, AUTH + tau*n, n);
}
if (tau == 0) {
SET_LTREE_ADDRESS(ltree_addr,leaf_idx);
@ -446,8 +451,6 @@ static void compute_authpath_wots_fast(unsigned char *root, unsigned char *authp
else {
SET_NODE_TREE_HEIGHT(node_addr, (tau-1));
SET_NODE_TREE_INDEX(node_addr, leaf_idx >> tau);
memcpy(buf, AUTH + (tau-1) * n, n);
memcpy(buf + n, KEEP + (tau-1) * n, n);
hash_2n_n(AUTH + tau * n, buf, pub_seed, node_addr, n);
for (i = 0; i < tau; i++) {
if (i < h - k) {