odd v2 plot k-sizes are not valid (#19933)

Author: arvidn

chia/_tests/core/custom_types/test_proof_of_space.py

@@ -14,6 +14,7 @@
 from chia.types.blockchain_format.proof_of_space import (
     calculate_plot_difficulty,
     calculate_prefix_bits,
+    check_plot_size,
     passes_plot_filter,
     verify_and_get_quality_string,
 )
@@ -221,6 +222,34 @@ def test_calculate_plot_difficulty(height: uint32, difficulty: uint8) -> None:
     assert calculate_plot_difficulty(DEFAULT_CONSTANTS, height) == difficulty
 
 
+@pytest.mark.parametrize(
+    "size, valid",
+    [
+        (PlotSize.make_v1(31), False),  # too small
+        (PlotSize.make_v1(32), True),
+        (PlotSize.make_v1(33), True),
+        (PlotSize.make_v1(34), True),
+        (PlotSize.make_v1(35), True),
+        (PlotSize.make_v1(36), True),
+        (PlotSize.make_v1(37), True),
+        (PlotSize.make_v1(49), True),
+        (PlotSize.make_v1(50), True),
+        (PlotSize.make_v1(51), False),  # too large
+        (PlotSize.make_v2(26), False),  # too small
+        (PlotSize.make_v2(27), False),  # too small (and odd)
+        (PlotSize.make_v2(28), True),
+        (PlotSize.make_v2(29), False),  # odd
+        (PlotSize.make_v2(30), True),
+        (PlotSize.make_v2(31), False),  # odd
+        (PlotSize.make_v2(32), True),
+        (PlotSize.make_v2(33), False),  # too large (and odd)
+        (PlotSize.make_v2(34), False),  # too large
+    ],
+)
+def test_check_plot_size(size: PlotSize, valid: bool) -> None:
+    assert check_plot_size(DEFAULT_CONSTANTS, size) == valid
+
+
 class TestProofOfSpace:
     @pytest.mark.parametrize("prefix_bits", [DEFAULT_CONSTANTS.NUMBER_ZERO_BITS_PLOT_FILTER_V1, 8, 7, 6, 5, 1, 0])
     def test_can_create_proof(self, prefix_bits: int, seeded_random: random.Random) -> None:

chia/types/blockchain_format/proof_of_space.py

@@ -50,6 +50,9 @@ def check_plot_size(constants: ConsensusConstants, ps: PlotSize) -> bool:
     if size_v2 > constants.MAX_PLOT_SIZE_V2:
         log.error("Plot size is higher than the maximum")
         return False
+    if (size_v2 & 1) == 1:
+        log.error("Plot size is odd")
+        return False
     return True