From 68ef46d836637a07e01255aeb54303c2ecd8f981 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Petr=20=C5=A0tetiar?= <ynezz@true.cz>
Date: Thu, 19 Nov 2020 16:32:46 +0100
Subject: [PATCH] download: handle possibly invalid local tarballs
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Currently it's assumed, that already downloaded tarballs are always
fine, so no checksum checking is performed and the tarball is used even
if it might be corrupted.

From now on, we're going to always check the downloaded tarballs before
considering them valid.

Steps to reproduce:

 1. Remove cached tarball

   rm dl/libubox-2020-08-06-9e52171d.tar.xz

 2. Download valid tarball again

   make package/libubox/download

 3. Invalidate the tarball

   sed -i 's/PKG_MIRROR_HASH:=../PKG_MIRROR_HASH:=ff/' package/libs/libubox/Makefile

 4. Now compile with corrupt tarball source

   make package/libubox/{clean,compile}

Signed-off-by: Petr Å tetiar <ynezz@true.cz>
(cherry picked from commit 4e19cbc553350b8146985367ba46514cf50e3393)
---
 include/host-build.mk |  2 ++
 include/package.mk    |  2 ++
 scripts/download.pl   | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/include/host-build.mk b/include/host-build.mk
index 827ea6bbfb..79a9b1f8d6 100644
--- a/include/host-build.mk
+++ b/include/host-build.mk
@@ -184,6 +184,8 @@ ifndef DUMP
     clean-build: host-clean-build
   endif
 
+  $(DL_DIR)/$(FILE): FORCE
+
   $(_host_target)host-prepare: $(HOST_STAMP_PREPARED)
   $(_host_target)host-configure: $(HOST_STAMP_CONFIGURED)
   $(_host_target)host-compile: $(HOST_STAMP_BUILT) $(HOST_STAMP_INSTALLED)
diff --git a/include/package.mk b/include/package.mk
index c541f6edf7..f6aa5ea8d0 100644
--- a/include/package.mk
+++ b/include/package.mk
@@ -185,6 +185,8 @@ define Build/CoreTargets
   $(call Build/Autoclean)
   $(call DefaultTargets)
 
+  $(DL_DIR)/$(FILE): FORCE
+
   download:
 	$(foreach hook,$(Hooks/Download),
 		$(call $(hook))$(sep)
diff --git a/scripts/download.pl b/scripts/download.pl
index 13fd5c8d8d..44a24b8d6f 100755
--- a/scripts/download.pl
+++ b/scripts/download.pl
@@ -271,6 +271,24 @@ foreach my $mirror (@ARGV) {
 
 push @mirrors, 'https://librecmc.org/librecmc/downloads/sources/v1.5';
 
+if (-f "$target/$filename") {
+	$hash_cmd and do {
+		if (system("cat '$target/$filename' | $hash_cmd > '$target/$filename.hash'")) {
+			die "Failed to generate hash for $filename\n";
+		}
+
+		my $sum = `cat "$target/$filename.hash"`;
+		$sum =~ /^(\w+)\s*/ or die "Could not generate file hash\n";
+		$sum = $1;
+
+		exit 0 if $sum eq $file_hash;
+
+		die "Hash of the local file $filename does not match (file: $sum, requested: $file_hash) - deleting download.\n";
+		unlink "$target/$filename";
+		cleanup();
+	};
+}
+
 while (!-f "$target/$filename") {
 	my $mirror = shift @mirrors;
 	$mirror or die "No more mirrors to try - giving up.\n";
-- 
2.25.1