From be4685ab7b6acc8ba0d383a6ae27453566046228 Mon Sep 17 00:00:00 2001
From: "Lesmiscore (Naoya Ozaki)" <nao20010128@gmail.com>
Date: Sat, 19 Mar 2022 10:15:01 +0900
Subject: [PATCH] [http] Reject broken range before request (#3079)

* And fix filesize estimate for byterange downloads

Closes #2001
Authored by: Lesmiscore, Jules-A, pukkandan
---
 yt_dlp/downloader/http.py | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/yt_dlp/downloader/http.py b/yt_dlp/downloader/http.py
index c2a57726ec..8e096b76b5 100644
--- a/yt_dlp/downloader/http.py
+++ b/yt_dlp/downloader/http.py
@@ -18,6 +18,7 @@
     parse_http_range,
     sanitized_Request,
     ThrottledDownload,
+    try_get,
     write_xattr,
     XAttrMetadataError,
     XAttrUnavailableError,
@@ -55,7 +56,6 @@ class DownloadContext(dict):
 
         ctx.open_mode = 'wb'
         ctx.resume_len = 0
-        ctx.data_len = None
         ctx.block_size = self.params.get('buffersize', 1024)
         ctx.start_time = time.time()
         ctx.chunk_size = None
@@ -102,6 +102,8 @@ def establish_connection():
                 if ctx.is_resume:
                     self.report_resuming_byte(ctx.resume_len)
                 ctx.open_mode = 'ab'
+            elif req_start is not None:
+                range_start = req_start
             elif ctx.chunk_size > 0:
                 range_start = 0
             else:
@@ -118,11 +120,16 @@ def establish_connection():
             else:
                 range_end = None
 
-            if range_end and ctx.data_len is not None and range_end >= ctx.data_len:
-                range_end = ctx.data_len - 1
-            has_range = range_start is not None
-            ctx.has_range = has_range
+            if try_get(None, lambda _: range_start > range_end):
+                ctx.resume_len = 0
+                ctx.open_mode = 'wb'
+                raise RetryDownload(Exception(f'Conflicting range. (start={range_start} > end={range_end})'))
+
+            if try_get(None, lambda _: range_end >= ctx.content_len):
+                range_end = ctx.content_len - 1
+
             request = sanitized_Request(url, request_data, headers)
+            has_range = range_start is not None
             if has_range:
                 set_range(request, range_start, range_end)
             # Establish connection
@@ -146,7 +153,8 @@ def establish_connection():
                             or content_range_end == range_end
                             or content_len < range_end)
                         if accept_content_len:
-                            ctx.data_len = content_len
+                            ctx.content_len = content_len
+                            ctx.data_len = min(content_len, req_end or content_len) - (req_start or 0)
                             return
                     # Content-Range is either not present or invalid. Assuming remote webserver is
                     # trying to send the whole file, resume is not possible, so wiping the local file
@@ -154,8 +162,7 @@ def establish_connection():
                     self.report_unable_to_resume()
                     ctx.resume_len = 0
                     ctx.open_mode = 'wb'
-                ctx.data_len = int_or_none(ctx.data.info().get('Content-length', None))
-                return
+                ctx.data_len = ctx.content_len = int_or_none(ctx.data.info().get('Content-length', None))
             except (compat_urllib_error.HTTPError, ) as err:
                 if err.code == 416:
                     # Unable to resume (requested range not satisfiable)
@@ -331,7 +338,7 @@ def retry(e):
                 elif speed:
                     throttle_start = None
 
-            if not is_test and ctx.chunk_size and ctx.data_len is not None and byte_counter < ctx.data_len:
+            if not is_test and ctx.chunk_size and ctx.content_len is not None and byte_counter < ctx.content_len:
                 ctx.resume_len = byte_counter
                 # ctx.block_size = block_size
                 raise NextFragment()