ee41743258
a Denial of Service attack against Cache Manager error responses
32 lines
1.3 KiB
Diff
32 lines
1.3 KiB
Diff
commit 8fcff9c09824b18628f010d26a04247f6a6cbcb8
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Author: Alex Rousskov <rousskov@measurement-factory.com>
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Date: Sun Nov 12 09:33:20 2023 +0000
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Do not update StoreEntry expiration after errorAppendEntry() (#1580)
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errorAppendEntry() is responsible for setting entry expiration times,
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which it does by calling StoreEntry::storeErrorResponse() that calls
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StoreEntry::negativeCache().
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This change was triggered by a vulnerability report by Joshua Rogers at
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https://megamansec.github.io/Squid-Security-Audit/cache-uaf.html where
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it was filed as "Use-After-Free in Cache Manager Errors". The reported
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"use after free" vulnerability was unknowingly addressed by 2022 commit
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1fa761a that removed excessively long "reentrant" store_client calls
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responsible for the disappearance of the properly locked StoreEntry in
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this (and probably other) contexts.
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diff --git a/src/cache_manager.cc b/src/cache_manager.cc
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index 8055ece..fdcc9cf 100644
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--- a/src/cache_manager.cc
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+++ b/src/cache_manager.cc
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@@ -323,7 +323,6 @@ CacheManager::Start(const Comm::ConnectionPointer &client, HttpRequest * request
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const auto err = new ErrorState(ERR_INVALID_URL, Http::scNotFound, request);
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err->url = xstrdup(entry->url());
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errorAppendEntry(entry, err);
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- entry->expires = squid_curtime;
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return;
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}
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