Fix LMS crash

Signed-off-by: Norman Ashley <[email protected]>
open-quantum-safe · Nov 19, 2024 · 764f62d · 764f62d
1 parent 507d030
commit 764f62d
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Showing 2 changed files with 10 additions and 10 deletions.
diff --git a/src/sig_stfl/lms/external/hss_alloc.c b/src/sig_stfl/lms/external/hss_alloc.c
@@ -164,11 +164,11 @@ struct hss_working_key *allocate_working_key(
     /* Assign the memory target to a *signed* variable; signed so that it */
     /* can take on negative values meaningfully (to account for cases where */
     /* we are "overbudget") */
-    unsigned long mem_target;
+    signed long mem_target;
     if (memory_target > LONG_MAX) {
         mem_target = LONG_MAX;
     } else {
-        mem_target = (unsigned long)memory_target;
+        mem_target = (signed long)memory_target;
     }
 #if 0
 signed long initial_mem_target = mem_target; /* DEBUG HACK */
@@ -179,7 +179,7 @@ signed long initial_mem_target = mem_target; /* DEBUG HACK */
         info->error_code = hss_error_out_of_memory;
         return NULL;
     }
-    mem_target -= (unsigned long)sizeof(*w) + MALLOC_OVERHEAD;
+    mem_target -= (signed long)sizeof(*w) + MALLOC_OVERHEAD;
     unsigned i;
     w->levels = levels;
     w->status = hss_error_key_uninitialized; /* Not usable until we see a */
@@ -221,13 +221,13 @@ signed long initial_mem_target = mem_target; /* DEBUG HACK */
             info->error_code = hss_error_out_of_memory;
             return 0;
         }
-        mem_target -= (unsigned long)w->signed_pk_len[i] + MALLOC_OVERHEAD;
+        mem_target -= (signed long)w->signed_pk_len[i] + MALLOC_OVERHEAD;
     }
     w->signature_len = signature_len;
 
     /* Also account for the overhead for the stack allocation (the memory */
     /* used by the stack will be accounted as a part of the tree level size */
-     mem_target -= (unsigned long)MALLOC_OVERHEAD;
+     mem_target -= (signed long)MALLOC_OVERHEAD;
 
     /*
      * Plot out how many subtree sizes we have at each level.  We start by
@@ -306,7 +306,7 @@ signed long initial_mem_target = mem_target; /* DEBUG HACK */
                        level_height[i], hash_size[i], &subtree_levels[i],
                         &stack_used );
 
-        mem_target -= (unsigned long)mem;
+        mem_target -= (signed long)mem;
         stack_usage += stack_used;
     }
 
@@ -362,7 +362,7 @@ signed long initial_mem_target = mem_target; /* DEBUG HACK */
             /* This is a signed type so that the comparison works as */
             /* expected if mem_target is negative */
         size_t stack_used;
-        unsigned long mem = (unsigned long)compute_level_memory_usage(i, j,
+        signed long mem = (unsigned long)compute_level_memory_usage(i, j,
                        level_height[i], hash_size[i], &subtree_levels[i],
                        &stack_used );
             /* # of sublevels this would have */

diff --git a/src/sig_stfl/lms/external/hss_sign.c b/src/sig_stfl/lms/external/hss_sign.c
@@ -594,8 +594,8 @@ bool hss_generate_signature(
     unsigned merkle_levels_below = 0;
     int switch_merkle = w->levels;
     struct merkle_level *tree;
-    for (i = w->levels; i>=1; i--, merkle_levels_below += tree->level) {
-        tree = w->tree[i-1];
+    for (i = w->levels-1; i>=1; i--, merkle_levels_below += tree->level) {
+        tree = w->tree[i];
 
         if (0 == (cur_count & (((sequence_t)1 << (merkle_levels_below + tree->level))-1))) {
             /* We exhausted this tree */
@@ -608,7 +608,7 @@ bool hss_generate_signature(
             }
 
             /* Remember we'll need to switch to the NEXT_TREE */
-            switch_merkle = i-1;
+            switch_merkle = i;
             continue;
         }