Description: ytdl_hook: whitelist protocols from urls retrieved from youtube-dl
 This patch is a combination of these upstream commits:
 - e6e6b0dcc7e9 ("ytdl_hook: whitelist protocols from urls retrieved from
   youtube-dl")
 - f8263e82cc74 ("ytdl_hook: move url_is_safe earlier in code")
 - ce42a965330d ("ytdl_hook: fix safe url checking with EDL urls")
 .
 jcowgill: backported to 0.27
 Fixes CVE-2018-6360
Author: Ricardo Constantino <wiiaboo@gmail.com>
Bug: https://github.com/mpv-player/mpv/issues/5456
Bug-Debian: https://bugs.debian.org/888654
Applied-Upstream: v0.29
---
This patch header follows DEP-3: http://dep.debian.net/deps/dep3/

--- a/player/lua/ytdl_hook.lua
+++ b/player/lua/ytdl_hook.lua
@@ -15,6 +15,18 @@ local ytdl = {
 
 local chapter_list = {}
 
+function Set (t)
+    local set = {}
+    for _, v in pairs(t) do set[v] = true end
+    return set
+end
+
+local safe_protos = Set {
+    "http", "https", "ftp", "ftps",
+    "rtmp", "rtmps", "rtmpe", "rtmpt", "rtmpts", "rtmpte",
+    "data"
+}
+
 local function exec(args)
     local ret = utils.subprocess({args = args})
     return ret.status, ret.stdout, ret
@@ -71,6 +83,15 @@ local function edl_escape(url)
     return "%" .. string.len(url) .. "%" .. url
 end
 
+local function url_is_safe(url)
+    local proto = type(url) == "string" and url:match("^(.+)://") or nil
+    local safe = proto and safe_protos[proto]
+    if not safe then
+        msg.error(("Ignoring potentially unsafe url: '%s'"):format(url))
+    end
+    return safe
+end
+
 local function time_to_secs(time_string)
     local ret
 
@@ -182,6 +203,9 @@ local function edl_track_joined(fragment
 
     for i = offset, #fragments do
         local fragment = fragments[i]
+        if not url_is_safe(join_url(base, fragment)) then
+            return nil
+        end
         table.insert(parts, edl_escape(join_url(base, fragment)))
         if fragment.duration then
             parts[#parts] =
@@ -201,6 +225,9 @@ local function add_single_video(json)
             edl_track = edl_track_joined(track.fragments,
                 track.protocol, json.is_live,
                 track.fragment_base_url)
+            if not edl_track and not url_is_safe(track.url) then
+                return
+            end
             if track.acodec and track.acodec ~= "none" then
                 -- audio track
                 mp.commandv("audio-add",
@@ -217,6 +244,9 @@ local function add_single_video(json)
         edl_track = edl_track_joined(json.fragments, json.protocol,
             json.is_live, json.fragment_base_url)
 
+        if not edl_track and not url_is_safe(json.url) then
+            return
+        end
         -- normal video or single track
         streamurl = edl_track or json.url
         set_http_headers(json.http_headers)
@@ -408,6 +438,10 @@ mp.add_hook("on_load", 10, function ()
 
                 msg.debug("EDL: " .. playlist)
 
+                if not playlist then
+                    return
+                end
+
                 -- can't change the http headers for each entry, so use the 1st
                 if json.entries[1] then
                     set_http_headers(json.entries[1].http_headers)
@@ -475,7 +509,9 @@ mp.add_hook("on_load", 10, function ()
                         site = entry["webpage_url"]
                     end
 
-                    playlist = playlist .. "ytdl://" .. site .. "\n"
+                    if url_is_safe(site) then
+                        playlist = playlist .. "ytdl://" .. site .. "\n"
+                    end
                 end
 
                 mp.set_property("stream-open-filename", "memory://" .. playlist)