From b7565c8bb9124be47bac62eddbace2bb852e623e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lubo=C5=A1=20Uhliarik?= Date: Wed, 23 Oct 2024 21:58:22 +0200 Subject: [PATCH] Resolves: RHEL-64426 - TCP_MISS_ABORTED/100 erros when uploading --- squid-6.10-large-upload-buffer-dies.patch | 117 ++++++++++++++++++++++ squid.spec | 7 +- 2 files changed, 123 insertions(+), 1 deletion(-) create mode 100644 squid-6.10-large-upload-buffer-dies.patch diff --git a/squid-6.10-large-upload-buffer-dies.patch b/squid-6.10-large-upload-buffer-dies.patch new file mode 100644 index 0000000..459d528 --- /dev/null +++ b/squid-6.10-large-upload-buffer-dies.patch @@ -0,0 +1,117 @@ +From 4d6dd3ddba5e850a42c86d8233735165a371c31c Mon Sep 17 00:00:00 2001 +From: Alex Rousskov +Date: Sun, 1 Sep 2024 00:39:34 +0000 +Subject: [PATCH] Bug 5405: Large uploads fill request buffer and die (#1887) + + maybeMakeSpaceAvailable: request buffer full + ReadNow: ... size 0, retval 0, errno 0 + terminateAll: 1/1 after ERR_CLIENT_GONE/WITH_CLIENT + %Ss=TCP_MISS_ABORTED + +This bug is triggered by a combination of the following two conditions: + +* HTTP client upload fills Squid request buffer faster than it is + drained by an origin server, cache_peer, or REQMOD service. The buffer + accumulates 576 KB (default 512 KB client_request_buffer_max_size + 64 + KB internal "pipe" buffer). + +* The affected server or service consumes a few bytes after the critical + accumulation is reached. In other words, the bug cannot be triggered + if nothing is consumed after the first condition above is met. + +Comm::ReadNow() must not be called with a full buffer: Related +FD_READ_METHOD() code cannot distinguish "received EOF" from "had no +buffer space" outcomes. Server::readSomeData() tried to prevent such +calls, but the corresponding check had two problems: + +* The check had an unsigned integer underflow bug[^1] that made it + ineffective when inBuf length exceeded Config.maxRequestBufferSize. + That length could exceed the limit due to reconfiguration and when + inBuf space size first grew outside of maybeMakeSpaceAvailable() + protections (e.g., during an inBuf.c_str() call) and then got filled + with newly read data. That growth started happening after 2020 commit + 1dfbca06 optimized SBuf::cow() to merge leading and trailing space. + Prior to that commit, Bug 5405 could probably only affect Squid + reconfigurations that lower client_request_buffer_max_size. + +* The check was separated from the ReadNow() call it was meant to + protect. While ConnStateData was waiting for the socket to become + ready for reading, various asynchronous events could alter inBuf or + Config.maxRequestBufferSize. + +This change fixes both problems. + +This change also fixes Squid Bug 5214. + +[^1]: That underflow bug was probably introduced in 2015 commit 4d1376d7 +while trying to emulate the original "do not read less than two bytes" +ConnStateData::In::maybeMakeSpaceAvailable() condition. That condition +itself looks like a leftover from manual zero-terminated input buffer +days that ended with 2014 commit e7287625. It is now removed. +--- + +diff --git a/src/servers/Server.cc b/src/servers/Server.cc +index 70fd10b..dd20619 100644 +--- a/src/servers/Server.cc ++++ b/src/servers/Server.cc +@@ -83,16 +83,25 @@ Server::maybeMakeSpaceAvailable() + debugs(33, 4, "request buffer full: client_request_buffer_max_size=" << Config.maxRequestBufferSize); + } + ++bool ++Server::mayBufferMoreRequestBytes() const ++{ ++ // TODO: Account for bodyPipe buffering as well. ++ if (inBuf.length() >= Config.maxRequestBufferSize) { ++ debugs(33, 4, "no: " << inBuf.length() << '-' << Config.maxRequestBufferSize << '=' << (inBuf.length() - Config.maxRequestBufferSize)); ++ return false; ++ } ++ debugs(33, 7, "yes: " << Config.maxRequestBufferSize << '-' << inBuf.length() << '=' << (Config.maxRequestBufferSize - inBuf.length())); ++ return true; ++} ++ + void + Server::readSomeData() + { + if (reading()) + return; + +- debugs(33, 4, clientConnection << ": reading request..."); +- +- // we can only read if there is more than 1 byte of space free +- if (Config.maxRequestBufferSize - inBuf.length() < 2) ++ if (!mayBufferMoreRequestBytes()) + return; + + typedef CommCbMemFunT Dialer; +@@ -123,7 +132,16 @@ Server::doClientRead(const CommIoCbParams &io) + * Plus, it breaks our lame *HalfClosed() detection + */ + ++ // mayBufferMoreRequestBytes() was true during readSomeData(), but variables ++ // like Config.maxRequestBufferSize may have changed since that check ++ if (!mayBufferMoreRequestBytes()) { ++ // XXX: If we avoid Comm::ReadNow(), we should not Comm::Read() again ++ // when the wait is over; resume these doClientRead() checks instead. ++ return; // wait for noteMoreBodySpaceAvailable() or a similar inBuf draining event ++ } + maybeMakeSpaceAvailable(); ++ Assure(inBuf.spaceSize()); ++ + CommIoCbParams rd(this); // will be expanded with ReadNow results + rd.conn = io.conn; + switch (Comm::ReadNow(rd, inBuf)) { +diff --git a/src/servers/Server.h b/src/servers/Server.h +index ef105f5..6e549b3 100644 +--- a/src/servers/Server.h ++++ b/src/servers/Server.h +@@ -119,6 +119,9 @@ protected: + /// abort any pending transactions and prevent new ones (by closing) + virtual void terminateAll(const Error &, const LogTagsErrors &) = 0; + ++ /// whether client_request_buffer_max_size allows inBuf.length() increase ++ bool mayBufferMoreRequestBytes() const; ++ + void doClientRead(const CommIoCbParams &io); + void clientWriteDone(const CommIoCbParams &io); + diff --git a/squid.spec b/squid.spec index 374b5a4..b1e88bc 100644 --- a/squid.spec +++ b/squid.spec @@ -2,7 +2,7 @@ Name: squid Version: 6.10 -Release: 2%{?dist} +Release: 3%{?dist} Summary: The Squid proxy caching server Epoch: 7 # See CREDITS for breakdown of non GPLv2+ code @@ -40,6 +40,8 @@ Patch204: squid-6.1-symlink-lang-err.patch Patch205: squid-6.1-crash-half-closed.patch # Upstream PR: https://github.com/squid-cache/squid/pull/1914 Patch206: squid-6.10-ignore-wsp-after-chunk-size.patch +# https://bugs.squid-cache.org/show_bug.cgi?id=5214 +Patch207: squid-6.10-large-upload-buffer-dies.patch # cache_swap.sh Requires: bash gawk @@ -326,6 +328,9 @@ fi %changelog +* Wed Oct 23 2024 Luboš Uhliarik - 7:6.10-3 +- Resolves: RHEL-64426 - TCP_MISS_ABORTED/100 erros when uploading + * Mon Oct 14 2024 Luboš Uhliarik - 7:6.10-2 - Resolves: RHEL-62323 - (Regression) Transfer-encoding:chunked data is not sent to the client in its complementary