[tor-commits] [tor/master] Fix ntohs() that should have been htons()

[nickm at torproject.org]

commit 3b646bf887f95c7f26ca05fb7fb3af10806b1328
Author: Nick Mathewson <nickm at torproject.org>
Date:   Fri Aug 4 12:17:53 2017 -0400

    Fix ntohs() that should have been htons()
    
    Fixes bug 23106; bugfix on 0.2.4.8-alpha.
    
    Fortunately, we only support big-endian and little-endian platforms,
    and on both of those, hton*() and ntoh*() behave the same.  And if
    we did start to support middle endian systems (haha, no), most of
    _those_ have hton*(x) == ntoh*(x) too.
---
 changes/bug23106 | 5 +++++
 src/or/onion.c   | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/changes/bug23106 b/changes/bug23106
new file mode 100644
index 000000000..d4ced15f8
--- /dev/null
+++ b/changes/bug23106
@@ -0,0 +1,5 @@
+  o Minor bugfixes (code correctness):
+    - Call htons() in extend_cell_format() for encoding a 16-bit
+      value. Previously we used ntohs(), which happens to behave the
+      same on all the platforms we support, but which isn't really
+      correct. Fixes bug 23106; bugfix on 0.2.4.8-alpha.
diff --git a/src/or/onion.c b/src/or/onion.c
index a98b97cb1..7e1e89df1 100644
--- a/src/or/onion.c
+++ b/src/or/onion.c
@@ -1219,7 +1219,7 @@ extend_cell_format(uint8_t *command_out, uint16_t *len_out,
       *command_out = RELAY_COMMAND_EXTEND;
       *len_out = 6 + TAP_ONIONSKIN_CHALLENGE_LEN + DIGEST_LEN;
       set_uint32(p, tor_addr_to_ipv4n(&cell_in->orport_ipv4.addr));
-      set_uint16(p+4, ntohs(cell_in->orport_ipv4.port));
+      set_uint16(p+4, htons(cell_in->orport_ipv4.port));
       if (cell_in->create_cell.handshake_type == ONION_HANDSHAKE_TYPE_NTOR) {
         memcpy(p+6, NTOR_CREATE_MAGIC, 16);
         memcpy(p+22, cell_in->create_cell.onionskin, NTOR_ONIONSKIN_LEN);