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authorDavid Kalnischkies <david@kalnischkies.de>2016-08-28 12:58:20 +0200
committerDavid Kalnischkies <david@kalnischkies.de>2016-08-29 09:22:25 +0200
commit4ff5e237d5685be187a75c563b86e80ea3e7cc01 (patch)
tree697f8b969cd205b6e28d441866bdfed38ee2b5b8 /apt-pkg
parent6a68315e938eb2611806658828ecea86805822e7 (diff)
randomize acquire order for same type index files
Without randomizing the order in which we download the index files we leak needlessly information to the mirrors of which architecture is native or foreign on this system. More importantly, we leak the order in which description translations will be used which in most cases will e.g. have the native tongue first. Note that the leak effect in practice is limited as apt detects if a file it wants to download is already available in the latest version from a previous download and does not query the server in such cases. Combined with the fact that Translation files are usually updated infrequently and not all at the same time, so a mirror can never be sure if it got asked about all files the user wants.
Diffstat (limited to 'apt-pkg')
-rw-r--r--apt-pkg/acquire-item.cc18
1 files changed, 18 insertions, 0 deletions
diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
index 91d7a3eae..0e1614330 100644
--- a/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@ -46,6 +46,7 @@
#include <ctime>
#include <sstream>
#include <numeric>
+#include <random>
#include <apti18n.h>
/*}}}*/
@@ -1340,6 +1341,23 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify) /*{{{*/
if (hasReleaseFile && verify == false)
hasHashes = std::any_of(IndexTargets.begin(), IndexTargets.end(),
[&](IndexTarget const &Target) { return TransactionManager->MetaIndexParser->Exists(Target.MetaKey); });
+ if (_config->FindB("Acquire::IndexTargets::Randomized", true) && likely(IndexTargets.empty() == false))
+ {
+ /* For fallback handling and to have some reasonable progress information
+ we can't randomize everything, but at least the order in the same type
+ can be as we shouldn't be telling the mirrors (and everyone else watching)
+ which is native/foreign arch, specific order of preference of translations, … */
+ auto range_start = IndexTargets.begin();
+ std::random_device rd;
+ std::default_random_engine g(rd());
+ do {
+ auto const type = range_start->Option(IndexTarget::CREATED_BY);
+ auto const range_end = std::find_if_not(range_start, IndexTargets.end(),
+ [&type](IndexTarget const &T) { return type == T.Option(IndexTarget::CREATED_BY); });
+ std::shuffle(range_start, range_end, g);
+ range_start = range_end;
+ } while (range_start != IndexTargets.end());
+ }
for (auto&& Target: IndexTargets)
{
// if we have seen a target which is created-by a target this one here is declared a