Merge pull request wolfSSL#55 from danielinux/wrapping-in-sack-reordering

Use correct comparison in SACK reordering to avoid wrapping errors

Author: gasbytes

src/test/unit/unit.c

@@ -10237,6 +10237,21 @@ START_TEST(test_tcp_sort_sack_blocks_swaps_out_of_order)
 }
 END_TEST
 
+START_TEST(test_tcp_sort_sack_blocks_wrap_order)
+{
+    struct tcp_sack_block blocks[2];
+
+    blocks[0].left = 0x00000010U;
+    blocks[0].right = 0x00000020U;
+    blocks[1].left = 0xFFFFFFF0U;
+    blocks[1].right = 0xFFFFFFF8U;
+
+    tcp_sort_sack_blocks(blocks, 2);
+    ck_assert_uint_eq(blocks[0].left, 0xFFFFFFF0U);
+    ck_assert_uint_eq(blocks[1].left, 0x00000010U);
+}
+END_TEST
+
 START_TEST(test_tcp_merge_sack_blocks_adjacent_and_disjoint)
 {
     struct tcp_sack_block blocks[3];
@@ -10255,6 +10270,23 @@ START_TEST(test_tcp_merge_sack_blocks_adjacent_and_disjoint)
 }
 END_TEST
 
+START_TEST(test_tcp_merge_sack_blocks_wrap_order)
+{
+    struct tcp_sack_block blocks[2];
+    uint8_t merged;
+
+    blocks[0].left = 0x00000010U;
+    blocks[0].right = 0x00000020U;
+    blocks[1].left = 0xFFFFFFF0U;
+    blocks[1].right = 0xFFFFFFF8U;
+
+    merged = tcp_merge_sack_blocks(blocks, 2);
+    ck_assert_uint_eq(merged, 2U);
+    ck_assert_uint_eq(blocks[0].left, 0xFFFFFFF0U);
+    ck_assert_uint_eq(blocks[1].left, 0x00000010U);
+}
+END_TEST
+
 START_TEST(test_tcp_recv_tracks_holes_and_sack_blocks)
 {
     struct wolfIP s;
@@ -17393,7 +17425,9 @@ Suite *wolf_suite(void)
     tcase_add_test(tc_utils, test_tcp_build_ack_options_does_not_write_past_returned_len);
     tcase_add_test(tc_utils, test_tcp_build_ack_options_omits_ts_when_not_negotiated);
     tcase_add_test(tc_utils, test_tcp_sort_sack_blocks_swaps_out_of_order);
+    tcase_add_test(tc_utils, test_tcp_sort_sack_blocks_wrap_order);
     tcase_add_test(tc_utils, test_tcp_merge_sack_blocks_adjacent_and_disjoint);
+    tcase_add_test(tc_utils, test_tcp_merge_sack_blocks_wrap_order);
     tcase_add_test(tc_utils, test_tcp_recv_tracks_holes_and_sack_blocks);
     tcase_add_test(tc_utils, test_tcp_rebuild_rx_sack_right_edge_wraps);
     tcase_add_test(tc_utils, test_tcp_consume_ooo_wrap_trim_and_promote);

src/wolfip.c

@@ -1887,7 +1887,7 @@ static void tcp_sort_sack_blocks(struct tcp_sack_block *blocks, uint8_t count)
     /* Small fixed-size sort (n <= 4) to normalize interval order before merge. */
     for (i = 0; i < count; i++) {
         for (j = (uint8_t)(i + 1); j < count; j++) {
-            if (blocks[j].left < blocks[i].left) {
+            if (tcp_seq_lt(blocks[j].left, blocks[i].left)) {
                 struct tcp_sack_block tmp = blocks[i];
                 blocks[i] = blocks[j];
                 blocks[j] = tmp;
@@ -1907,8 +1907,8 @@ static uint8_t tcp_merge_sack_blocks(struct tcp_sack_block *blocks, uint8_t coun
      * - gap: keep as separate ranges */
     tcp_sort_sack_blocks(blocks, count);
     for (i = 1; i < count; i++) {
-        if (blocks[i].left < blocks[out].right) {
-            if (blocks[i].right > blocks[out].right)
+        if (tcp_seq_lt(blocks[i].left, blocks[out].right)) {
+            if (!tcp_seq_leq(blocks[i].right, blocks[out].right))
                 blocks[out].right = blocks[i].right;
         } else if (blocks[i].left == blocks[out].right) {
             blocks[out].right = blocks[i].right;