From 5481fd8af692b7e24b4e904b115ea6a1f80e6a0b Mon Sep 17 00:00:00 2001
From: SomberNight <somber.night@protonmail.com>
Date: Mon, 26 Oct 2020 02:07:30 +0100
Subject: [PATCH] interface: validate field order in
 "mempool.get_fee_histogram" response

---
 electrum/interface.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/electrum/interface.py b/electrum/interface.py
index f3a862a6d..de2364549 100644
--- a/electrum/interface.py
+++ b/electrum/interface.py
@@ -993,9 +993,13 @@ class Interface(Logger):
         res = await self.session.send_request('mempool.get_fee_histogram')
         # check response
         assert_list_or_tuple(res)
+        prev_fee = float('inf')
         for fee, s in res:
             assert_non_negative_int_or_float(fee)
             assert_non_negative_integer(s)
+            if fee >= prev_fee:  # check monotonicity
+                raise RequestCorrupted(f'fees must be in decreasing order')
+            prev_fee = fee
         return res
 
     async def get_server_banner(self) -> str: