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hs_pow_solve: use equix_solve more efficiently

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This was apparently misinterpreting "zero solutions" as an error
instead of just moving on to the next nonce. Additionally, equix
could have been returning up to 8 solutions and we would only
give one of those a chance to succeed.

Signed-off-by: Micah Elizabeth Scott <beth@torproject.org>
This commit is contained in:
Micah Elizabeth Scott 2023-03-01 16:46:25 -08:00
parent 0e271dda77
commit 557eb81486
1 changed files with 24 additions and 35 deletions
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59
src/feature/hs/hs_pow.c
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@ -146,46 +146,35 @@ hs_pow_solve(const hs_pow_desc_params_t *pow_params,
challenge = build_equix_challenge(pow_params->seed, nonce, effort);
ctx = equix_alloc(EQUIX_CTX_SOLVE);
equix_solution solution[EQUIX_MAX_SOLS];
equix_solution solutions[EQUIX_MAX_SOLS];
/* We'll do a maximum of the nonce size iterations here which is the maximum
* number of nonce we can try in an attempt to find a valid solution. */
log_notice(LD_REND, "Solving proof of work (effort %u)", effort);
for (uint64_t i = 0; i < UINT64_MAX; i++) {
/* Calculate S = equix_solve(C || N || E) */
if (!equix_solve(ctx, challenge, HS_POW_CHALLENGE_LEN, solution)) {
ret = -1;
goto end;
}
const equix_solution *sol = &solution[0];
for (;;) {
/* Calculate solutions to S = equix_solve(C || N || E), */
int count = equix_solve(ctx, challenge, HS_POW_CHALLENGE_LEN, solutions);
for (int i = 0; i < count; i++) {
const equix_solution *sol = &solutions[i];
equix_result result = equix_verify(ctx, challenge,
HS_POW_CHALLENGE_LEN, sol);
if (result != EQUIX_OK) {
/* Go again with a new nonce. */
increment_and_set_nonce(&nonce, challenge);
continue;
/* Check an Equi-X solution against the effort threshold */
if (validate_equix_challenge(challenge, sol, effort)) {
/* Store the nonce N. */
pow_solution_out->nonce = nonce;
/* Store the effort E. */
pow_solution_out->effort = effort;
/* We only store the first 4 bytes of the seed C. */
pow_solution_out->seed_head = get_uint32(pow_params->seed);
/* Store the solution S */
memcpy(&pow_solution_out->equix_solution, sol,
sizeof(pow_solution_out->equix_solution));
/* Indicate success and we are done. */
ret = 0;
goto end;
}
}
/* Validate the challenge against the solution. */
if (validate_equix_challenge(challenge, sol, effort)) {
/* Store the nonce N. */
pow_solution_out->nonce = nonce;
/* Store the effort E. */
pow_solution_out->effort = effort;
/* We only store the first 4 bytes of the seed C. */
pow_solution_out->seed_head = get_uint32(pow_params->seed);
/* Store the solution S */
memcpy(&pow_solution_out->equix_solution, sol,
sizeof(pow_solution_out->equix_solution));
/* Indicate success and we are done. */
ret = 0;
break;
}
/* Did not pass the R * E <= UINT32_MAX check. Increment the nonce and
* try again. */
/* No solutions for this nonce and/or none that passed the effort
* threshold, increment and try again. */
increment_and_set_nonce(&nonce, challenge);
}