hs_pow: Update for equix API to fix issue 40794

This change adapts the hs_pow layer and unit tests to API changes
in hashx and equix which modify the fault recovery responsibilities
and reporting behaivor.

This and the corresponding implementation changes in hashx and equix
form the fix for #40794, both solving the segfault and giving hashx a
way to report those failures up the call chain without them being
mistaken for a different error (unusable seed) that would warrant a
retry.

To handle these new late compiler failures with a minimum of fuss or
inefficiency, the failover is delegated to the internals of hashx and
tor needs only pass in a EQUIX_CTX_TRY_COMPILE flag to get the behavior
that tor was previously responsible for implementing.

Signed-off-by: Micah Elizabeth Scott <beth@torproject.org>

3 files changed, 49 insertions, 53 deletions

diff --git a/src/test/test_crypto.c b/src/test/test_crypto.c
index 926d4178c1..db5a2db650 100644
--- a/src/test/test_crypto.c
+++ b/src/test/test_crypto.c
@@ -2982,9 +2982,9 @@ test_crypto_hashx(void *arg)
   static const struct {
     hashx_type type;
   } variations[] = {
-    { HASHX_INTERPRETED },
+    { HASHX_TYPE_INTERPRETED },
 #if defined(_M_X64) || defined(__x86_64__) || defined(__aarch64__)
-    { HASHX_COMPILED },
+    { HASHX_TYPE_COMPILED },
 #endif
   };
 
@@ -3013,12 +3013,12 @@ test_crypto_hashx(void *arg)
       ctx = hashx_alloc(variations[vari_i].type);
 
       tt_ptr_op(ctx, OP_NE, NULL);
-      tt_ptr_op(ctx, OP_NE, HASHX_NOTSUPP);
       retval = hashx_make(ctx, seed_literal, seed_len);
-      tt_int_op(retval, OP_EQ, 1);
+      tt_int_op(retval, OP_EQ, HASHX_OK);
 
       memset(out_actual, 0xa5, sizeof out_actual);
-      hashx_exec(ctx, hash_input, out_actual);
+      retval = hashx_exec(ctx, hash_input, out_actual);
+      tt_int_op(retval, OP_EQ, HASHX_OK);
       tt_mem_op(out_actual, OP_EQ, out_expected, sizeof out_actual);
     }
   }
diff --git a/src/test/test_crypto_slow.c b/src/test/test_crypto_slow.c
index 5ffd199813..23bc7a852f 100644
--- a/src/test/test_crypto_slow.c
+++ b/src/test/test_crypto_slow.c
@@ -636,14 +636,21 @@ test_crypto_equix(void *arg)
   static const struct {
     equix_ctx_flags flags;
     equix_result expected;
+    equix_solution_flags sol_flags;
   } variations[] = {
-    {0, EQUIX_OK},
-    {0, EQUIX_ORDER},
-    {0, EQUIX_PARTIAL_SUM},
+    {0, EQUIX_OK, 0},
+    {0, EQUIX_FAIL_ORDER, 0},
+    {0, EQUIX_FAIL_PARTIAL_SUM, 0},
 #if defined(_M_X64) || defined(__x86_64__) || defined(__aarch64__)
-    {EQUIX_CTX_COMPILE, EQUIX_OK},
-    {EQUIX_CTX_COMPILE, EQUIX_ORDER},
-    {EQUIX_CTX_COMPILE, EQUIX_PARTIAL_SUM},
+    { EQUIX_CTX_MUST_COMPILE, EQUIX_OK,
+      EQUIX_SOLVER_DID_USE_COMPILER
+    },
+    { EQUIX_CTX_MUST_COMPILE, EQUIX_FAIL_ORDER,
+      EQUIX_SOLVER_DID_USE_COMPILER
+    },
+    { EQUIX_CTX_MUST_COMPILE, EQUIX_FAIL_PARTIAL_SUM,
+      EQUIX_SOLVER_DID_USE_COMPILER
+    },
 #endif
   };
 
@@ -659,48 +666,42 @@ test_crypto_equix(void *arg)
 
     for (unsigned vari_i = 0; vari_i < num_variations; vari_i++) {
       const equix_ctx_flags flags = variations[vari_i].flags;
+      const equix_solution_flags sol_flags = variations[vari_i].sol_flags;
       const equix_result expected = variations[vari_i].expected;
 
-      equix_solution sols_actual[EQUIX_MAX_SOLS];
+      equix_solutions_buffer output;
       equix_ctx *solve_ctx = NULL, *verify_ctx = NULL;
 
       solve_ctx = equix_alloc(EQUIX_CTX_SOLVE | flags);
       tt_ptr_op(solve_ctx, OP_NE, NULL);
-      tt_ptr_op(solve_ctx, OP_NE, EQUIX_NOTSUPP);
 
       /* Solve phase: Make sure the test vector matches */
-      memset(sols_actual, 0xa5, sizeof sols_actual);
-      int retval = equix_solve(solve_ctx, challenge_literal,
-                               challenge_len, sols_actual);
-      tt_int_op(retval, OP_EQ, num_sols);
-      tt_mem_op(sols_actual, OP_EQ, sols_expected,
+      memset(&output, 0xa5, sizeof output);
+      equix_result result;
+      result = equix_solve(solve_ctx, challenge_literal,
+                           challenge_len, &output);
+      tt_int_op(result, OP_EQ, EQUIX_OK);
+      tt_int_op(output.count, OP_EQ, num_sols);
+      tt_int_op(output.flags, OP_EQ, sol_flags);
+      tt_mem_op(output.sols, OP_EQ, sols_expected,
                 num_sols * sizeof(equix_solution));
 
       verify_ctx = equix_alloc(EQUIX_CTX_VERIFY | flags);
       tt_ptr_op(verify_ctx, OP_NE, NULL);
-      tt_ptr_op(verify_ctx, OP_NE, EQUIX_NOTSUPP);
 
       /* Use each solution for positive and negative tests of verify */
       for (size_t sol_i = 0; sol_i < num_sols; sol_i++) {
-        equix_result result;
         equix_idx tmp_idx;
-        equix_solution *sol = &sols_actual[sol_i];
-
-        switch (expected) {
-          case EQUIX_ORDER:
-            /* Swap two otherwise valid indices, to trigger an order error */
-            tmp_idx = sol->idx[0];
-            sol->idx[0] = sol->idx[1];
-            sol->idx[1] = tmp_idx;
-            break;
-          case EQUIX_FINAL_SUM:
-          case EQUIX_PARTIAL_SUM:
-            /* Most changes to the solution will cause a partial sum error */
-            sol->idx[0]++;
-            break;
-          case EQUIX_OK:
-          case EQUIX_CHALLENGE:
-            break;
+        equix_solution *sol = &output.sols[sol_i];
+
+        if (expected == EQUIX_FAIL_ORDER) {
+          /* Swap two otherwise valid indices, to trigger an order error */
+          tmp_idx = sol->idx[0];
+          sol->idx[0] = sol->idx[1];
+          sol->idx[1] = tmp_idx;
+        } else if (expected == EQUIX_FAIL_PARTIAL_SUM) {
+          /* Most changes to the solution will cause a partial sum error */
+          sol->idx[0]++;
         }
 
         result = equix_verify(verify_ctx, challenge_literal,
diff --git a/src/test/test_sandbox.c b/src/test/test_sandbox.c
index a28c9b6e41..64182ecc91 100644
--- a/src/test/test_sandbox.c
+++ b/src/test/test_sandbox.c
@@ -315,32 +315,27 @@ test_sandbox_crypto_equix(void *arg)
     {{ 0x62c5, 0x86d1, 0x5752, 0xe1f0, 0x12da, 0x8f33, 0x7336, 0xf161 }},
   };
 
-  equix_solution sols_actual[EQUIX_MAX_SOLS] = { 0 };
+  equix_solutions_buffer output;
   equix_ctx *solve_ctx = NULL, *verify_ctx = NULL;
 
-  /* TODO: A subsequent change will modify these flags to use an auto fallback
-   *       that will be built into our fork of equix. (This implements a
-   *       performant and low-complexity way to share the generated program
-   *       state during fallback instead of re-generating it.)
-   */
-  solve_ctx = equix_alloc(EQUIX_CTX_SOLVE | EQUIX_CTX_COMPILE);
+  solve_ctx = equix_alloc(EQUIX_CTX_SOLVE | EQUIX_CTX_TRY_COMPILE);
   tt_ptr_op(solve_ctx, OP_NE, NULL);
-  tt_ptr_op(solve_ctx, OP_NE, EQUIX_NOTSUPP);
 
-  int retval = equix_solve(solve_ctx, challenge_literal,
-                           challenge_len, sols_actual);
-  tt_int_op(retval, OP_EQ, num_sols);
-  tt_mem_op(sols_actual, OP_EQ, sols_expected,
+  equix_result result;
+  memset(&output, 0xEE, sizeof output);
+  result = equix_solve(solve_ctx, challenge_literal, challenge_len, &output);
+  tt_int_op(result, OP_EQ, EQUIX_OK);
+  tt_int_op(output.count, OP_EQ, num_sols);
+  tt_int_op(output.flags, OP_EQ, 0); /* EQUIX_SOLVER_DID_USE_COMPILER unset */
+  tt_mem_op(output.sols, OP_EQ, sols_expected,
             num_sols * sizeof(equix_solution));
 
-  verify_ctx = equix_alloc(EQUIX_CTX_VERIFY | EQUIX_CTX_COMPILE);
+  verify_ctx = equix_alloc(EQUIX_CTX_VERIFY | EQUIX_CTX_TRY_COMPILE);
   tt_ptr_op(verify_ctx, OP_NE, NULL);
-  tt_ptr_op(verify_ctx, OP_NE, EQUIX_NOTSUPP);
 
   /* Test one of the solutions randomly */
-  equix_result result;
   const unsigned sol_i = crypto_rand_int(num_sols);
-  equix_solution *sol = &sols_actual[sol_i];
+  equix_solution *sol = &output.sols[sol_i];
 
   result = equix_verify(verify_ctx, challenge_literal,
                         challenge_len, sol);