parent
015015e8b6
commit
2cbbaf7812
@ -0,0 +1,50 @@
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diff --git a/src/ClientRequestContext.h b/src/ClientRequestContext.h
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index 55a7a43..94a8700 100644
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--- a/src/ClientRequestContext.h
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+++ b/src/ClientRequestContext.h
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@@ -80,6 +80,10 @@ public:
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#endif
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ErrorState *error; ///< saved error page for centralized/delayed processing
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bool readNextRequest; ///< whether Squid should read after error handling
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+
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+#if FOLLOW_X_FORWARDED_FOR
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+ size_t currentXffHopNumber = 0; ///< number of X-Forwarded-For header values processed so far
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+#endif
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};
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#endif /* SQUID_CLIENTREQUESTCONTEXT_H */
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diff --git a/src/client_side_request.cc b/src/client_side_request.cc
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index f44849e..c7c09d4 100644
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--- a/src/client_side_request.cc
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+++ b/src/client_side_request.cc
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@@ -80,6 +80,11 @@
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static const char *const crlf = "\r\n";
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#if FOLLOW_X_FORWARDED_FOR
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+
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+#if !defined(SQUID_X_FORWARDED_FOR_HOP_MAX)
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+#define SQUID_X_FORWARDED_FOR_HOP_MAX 64
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+#endif
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+
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static void clientFollowXForwardedForCheck(Acl::Answer answer, void *data);
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#endif /* FOLLOW_X_FORWARDED_FOR */
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@@ -485,8 +490,16 @@ clientFollowXForwardedForCheck(Acl::Answer answer, void *data)
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/* override the default src_addr tested if we have to go deeper than one level into XFF */
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Filled(calloutContext->acl_checklist)->src_addr = request->indirect_client_addr;
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}
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- calloutContext->acl_checklist->nonBlockingCheck(clientFollowXForwardedForCheck, data);
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- return;
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+ if (++calloutContext->currentXffHopNumber < SQUID_X_FORWARDED_FOR_HOP_MAX) {
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+ calloutContext->acl_checklist->nonBlockingCheck(clientFollowXForwardedForCheck, data);
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+ return;
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+ }
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+ const auto headerName = Http::HeaderLookupTable.lookup(Http::HdrType::X_FORWARDED_FOR).name;
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+ debugs(28, DBG_CRITICAL, "ERROR: Ignoring trailing " << headerName << " addresses" <<
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+ Debug::Extra << "addresses allowed by follow_x_forwarded_for: " << calloutContext->currentXffHopNumber <<
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+ Debug::Extra << "last/accepted address: " << request->indirect_client_addr <<
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+ Debug::Extra << "ignored trailing addresses: " << request->x_forwarded_for_iterator);
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+ // fall through to resume clientAccessCheck() processing
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}
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}
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|
@ -0,0 +1,192 @@
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diff --git a/src/http.cc b/src/http.cc
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index 98e3969..8b55bf3 100644
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--- a/src/http.cc
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+++ b/src/http.cc
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@@ -54,6 +54,7 @@
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#include "rfc1738.h"
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#include "SquidConfig.h"
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#include "SquidTime.h"
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+#include "SquidMath.h"
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#include "StatCounters.h"
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#include "Store.h"
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#include "StrList.h"
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@@ -1235,18 +1236,26 @@ HttpStateData::readReply(const CommIoCbParams &io)
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* Plus, it breaks our lame *HalfClosed() detection
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*/
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- Must(maybeMakeSpaceAvailable(true));
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- CommIoCbParams rd(this); // will be expanded with ReadNow results
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- rd.conn = io.conn;
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- rd.size = entry->bytesWanted(Range<size_t>(0, inBuf.spaceSize()));
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+ const auto moreDataPermission = canBufferMoreReplyBytes();
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+ if (!moreDataPermission) {
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+ abortTransaction("ready to read required data, but the read buffer is full and cannot be drained");
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+ return;
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+ }
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+
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+ const auto readSizeMax = maybeMakeSpaceAvailable(moreDataPermission.value());
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+ // TODO: Move this logic inside maybeMakeSpaceAvailable():
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+ const auto readSizeWanted = readSizeMax ? entry->bytesWanted(Range<size_t>(0, readSizeMax)) : 0;
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- if (rd.size <= 0) {
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+ if (readSizeWanted <= 0) {
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assert(entry->mem_obj);
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AsyncCall::Pointer nilCall;
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entry->mem_obj->delayRead(DeferredRead(readDelayed, this, CommRead(io.conn, NULL, 0, nilCall)));
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return;
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}
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+ CommIoCbParams rd(this); // will be expanded with ReadNow results
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+ rd.conn = io.conn;
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+ rd.size = readSizeWanted;
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switch (Comm::ReadNow(rd, inBuf)) {
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case Comm::INPROGRESS:
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if (inBuf.isEmpty())
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@@ -1617,8 +1626,10 @@ HttpStateData::maybeReadVirginBody()
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if (!Comm::IsConnOpen(serverConnection) || fd_table[serverConnection->fd].closing())
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return;
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- if (!maybeMakeSpaceAvailable(false))
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+ if (!canBufferMoreReplyBytes()) {
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+ abortTransaction("more response bytes required, but the read buffer is full and cannot be drained");
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return;
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+ }
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// XXX: get rid of the do_next_read flag
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// check for the proper reasons preventing read(2)
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@@ -1636,40 +1647,78 @@ HttpStateData::maybeReadVirginBody()
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Comm::Read(serverConnection, call);
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}
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-bool
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-HttpStateData::maybeMakeSpaceAvailable(bool doGrow)
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+/// Desired inBuf capacity based on various capacity preferences/limits:
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+/// * a smaller buffer may not hold enough for look-ahead header/body parsers;
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+/// * a smaller buffer may result in inefficient tiny network reads;
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+/// * a bigger buffer may waste memory;
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+/// * a bigger buffer may exceed SBuf storage capabilities (SBuf::maxSize);
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+size_t
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+HttpStateData::calcReadBufferCapacityLimit() const
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{
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- // how much we are allowed to buffer
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- const int limitBuffer = (flags.headers_parsed ? Config.readAheadGap : Config.maxReplyHeaderSize);
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-
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- if (limitBuffer < 0 || inBuf.length() >= (SBuf::size_type)limitBuffer) {
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- // when buffer is at or over limit already
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- debugs(11, 7, "will not read up to " << limitBuffer << ". buffer has (" << inBuf.length() << "/" << inBuf.spaceSize() << ") from " << serverConnection);
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- debugs(11, DBG_DATA, "buffer has {" << inBuf << "}");
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- // Process next response from buffer
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- processReply();
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- return false;
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+ if (!flags.headers_parsed)
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+ return Config.maxReplyHeaderSize;
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+
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+ // XXX: Our inBuf is not used to maintain the read-ahead gap, and using
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+ // Config.readAheadGap like this creates huge read buffers for large
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+ // read_ahead_gap values. TODO: Switch to using tcp_recv_bufsize as the
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+ // primary read buffer capacity factor.
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+ //
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+ // TODO: Cannot reuse throwing NaturalCast() here. Consider removing
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+ // .value() dereference in NaturalCast() or add/use NaturalCastOrMax().
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+ const auto configurationPreferences = NaturalSum<size_t>(Config.readAheadGap).value_or(SBuf::maxSize);
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+
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+ // TODO: Honor TeChunkedParser look-ahead and trailer parsing requirements
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+ // (when explicit configurationPreferences are set too low).
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+
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+ return std::min<size_t>(configurationPreferences, SBuf::maxSize);
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+}
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+
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+/// The maximum number of virgin reply bytes we may buffer before we violate
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+/// the currently configured response buffering limits.
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+/// \retval std::nullopt means that no more virgin response bytes can be read
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+/// \retval 0 means that more virgin response bytes may be read later
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+/// \retval >0 is the number of bytes that can be read now (subject to other constraints)
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+std::optional<size_t>
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+HttpStateData::canBufferMoreReplyBytes() const
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+{
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+#if USE_ADAPTATION
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+ // If we do not check this now, we may say the final "no" prematurely below
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+ // because inBuf.length() will decrease as adaptation drains buffered bytes.
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+ if (responseBodyBuffer) {
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+ debugs(11, 3, "yes, but waiting for adaptation to drain read buffer");
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+ return 0; // yes, we may be able to buffer more (but later)
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+ }
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+#endif
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+
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+ const auto maxCapacity = calcReadBufferCapacityLimit();
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+ if (inBuf.length() >= maxCapacity) {
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+ debugs(11, 3, "no, due to a full buffer: " << inBuf.length() << '/' << inBuf.spaceSize() << "; limit: " << maxCapacity);
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+ return std::nullopt; // no, configuration prohibits buffering more
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}
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+ const auto maxReadSize = maxCapacity - inBuf.length(); // positive
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+ debugs(11, 7, "yes, may read up to " << maxReadSize << " into " << inBuf.length() << '/' << inBuf.spaceSize());
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+ return maxReadSize; // yes, can read up to this many bytes (subject to other constraints)
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+}
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+
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+/// prepare read buffer for reading
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+/// \return the maximum number of bytes the caller should attempt to read
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+/// \retval 0 means that the caller should delay reading
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+size_t
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+HttpStateData::maybeMakeSpaceAvailable(const size_t maxReadSize)
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+{
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// how much we want to read
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- const size_t read_size = calcBufferSpaceToReserve(inBuf.spaceSize(), (limitBuffer - inBuf.length()));
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+ const size_t read_size = calcBufferSpaceToReserve(inBuf.spaceSize(), maxReadSize);
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- if (!read_size) {
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+ if (read_size < 2) {
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debugs(11, 7, "will not read up to " << read_size << " into buffer (" << inBuf.length() << "/" << inBuf.spaceSize() << ") from " << serverConnection);
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- return false;
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+ return 0;
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}
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- // just report whether we could grow or not, do not actually do it
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- if (doGrow)
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- return (read_size >= 2);
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-
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// we may need to grow the buffer
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inBuf.reserveSpace(read_size);
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- debugs(11, 8, (!flags.do_next_read ? "will not" : "may") <<
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- " read up to " << read_size << " bytes info buf(" << inBuf.length() << "/" << inBuf.spaceSize() <<
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- ") from " << serverConnection);
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-
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- return (inBuf.spaceSize() >= 2); // only read if there is 1+ bytes of space available
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+ debugs(11, 7, "may read up to " << read_size << " bytes info buffer (" << inBuf.length() << "/" << inBuf.spaceSize() << ") from " << serverConnection);
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+ return read_size;
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}
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/// called after writing the very last request byte (body, last-chunk, etc)
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diff --git a/src/http.h b/src/http.h
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index e70cd7e..f7ed40d 100644
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--- a/src/http.h
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+++ b/src/http.h
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@@ -15,6 +15,8 @@
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#include "http/StateFlags.h"
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#include "sbuf/SBuf.h"
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+#include <optional>
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+
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class FwdState;
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class HttpHeader;
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class String;
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@@ -112,16 +114,9 @@ private:
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void abortTransaction(const char *reason) { abortAll(reason); } // abnormal termination
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- /**
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- * determine if read buffer can have space made available
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- * for a read.
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- *
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- * \param grow whether to actually expand the buffer
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- *
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- * \return whether the buffer can be grown to provide space
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- * regardless of whether the grow actually happened.
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- */
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- bool maybeMakeSpaceAvailable(bool grow);
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+ size_t calcReadBufferCapacityLimit() const;
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+ std::optional<size_t> canBufferMoreReplyBytes() const;
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+ size_t maybeMakeSpaceAvailable(size_t maxReadSize);
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// consuming request body
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virtual void handleMoreRequestBodyAvailable();
|
@ -0,0 +1,105 @@
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diff --git a/src/SquidString.h b/src/SquidString.h
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index e36cd27..ea613ad 100644
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--- a/src/SquidString.h
|
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+++ b/src/SquidString.h
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||||
@@ -140,7 +140,16 @@ private:
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|
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size_type len_ = 0; /* current length */
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- static const size_type SizeMax_ = 65535; ///< 64K limit protects some fixed-size buffers
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+ /// An earlier 64KB limit was meant to protect some fixed-size buffers, but
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+ /// (a) we do not know where those buffers are (or whether they still exist)
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+ /// (b) too many String users unknowingly exceeded that limit and asserted.
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+ /// We are now using a larger limit to reduce the number of (b) cases,
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+ /// especially cases where "compact" lists of items grow 50% in size when we
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+ /// convert them to canonical form. The new limit is selected to withstand
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+ /// concatenation and ~50% expansion of two HTTP headers limited by default
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+ /// request_header_max_size and reply_header_max_size settings.
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+ static const size_type SizeMax_ = 3*64*1024 - 1;
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+
|
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/// returns true after increasing the first argument by extra if the sum does not exceed SizeMax_
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static bool SafeAdd(size_type &base, size_type extra) { if (extra <= SizeMax_ && base <= SizeMax_ - extra) { base += extra; return true; } return false; }
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||||
|
||||
diff --git a/src/cache_cf.cc b/src/cache_cf.cc
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||||
index cb746dc..c4ade96 100644
|
||||
--- a/src/cache_cf.cc
|
||||
+++ b/src/cache_cf.cc
|
||||
@@ -950,6 +950,18 @@ configDoConfigure(void)
|
||||
(uint32_t)Config.maxRequestBufferSize, (uint32_t)Config.maxRequestHeaderSize);
|
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}
|
||||
|
||||
+ // Warn about the dangers of exceeding String limits when manipulating HTTP
|
||||
+ // headers. Technically, we do not concatenate _requests_, so we could relax
|
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+ // their check, but we keep the two checks the same for simplicity sake.
|
||||
+ const auto safeRawHeaderValueSizeMax = (String::SizeMaxXXX()+1)/3;
|
||||
+ // TODO: static_assert(safeRawHeaderValueSizeMax >= 64*1024); // no WARNINGs for default settings
|
||||
+ if (Config.maxRequestHeaderSize > safeRawHeaderValueSizeMax)
|
||||
+ debugs(3, DBG_CRITICAL, "WARNING: Increasing request_header_max_size beyond " << safeRawHeaderValueSizeMax <<
|
||||
+ " bytes makes Squid more vulnerable to denial-of-service attacks; configured value: " << Config.maxRequestHeaderSize << " bytes");
|
||||
+ if (Config.maxReplyHeaderSize > safeRawHeaderValueSizeMax)
|
||||
+ debugs(3, DBG_CRITICAL, "WARNING: Increasing reply_header_max_size beyond " << safeRawHeaderValueSizeMax <<
|
||||
+ " bytes makes Squid more vulnerable to denial-of-service attacks; configured value: " << Config.maxReplyHeaderSize << " bytes");
|
||||
+
|
||||
/*
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||||
* Disable client side request pipelining if client_persistent_connections OFF.
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||||
* Waste of resources queueing any pipelined requests when the first will close the connection.
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||||
diff --git a/src/cf.data.pre b/src/cf.data.pre
|
||||
index 67a66b0..61a66f1 100644
|
||||
--- a/src/cf.data.pre
|
||||
+++ b/src/cf.data.pre
|
||||
@@ -6489,11 +6489,14 @@ TYPE: b_size_t
|
||||
DEFAULT: 64 KB
|
||||
LOC: Config.maxRequestHeaderSize
|
||||
DOC_START
|
||||
- This specifies the maximum size for HTTP headers in a request.
|
||||
- Request headers are usually relatively small (about 512 bytes).
|
||||
- Placing a limit on the request header size will catch certain
|
||||
- bugs (for example with persistent connections) and possibly
|
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- buffer-overflow or denial-of-service attacks.
|
||||
+ This directives limits the header size of a received HTTP request
|
||||
+ (including request-line). Increasing this limit beyond its 64 KB default
|
||||
+ exposes certain old Squid code to various denial-of-service attacks. This
|
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+ limit also applies to received FTP commands.
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||||
+
|
||||
+ This limit has no direct affect on Squid memory consumption.
|
||||
+
|
||||
+ Squid does not check this limit when sending requests.
|
||||
DOC_END
|
||||
|
||||
NAME: reply_header_max_size
|
||||
@@ -6502,11 +6505,14 @@ TYPE: b_size_t
|
||||
DEFAULT: 64 KB
|
||||
LOC: Config.maxReplyHeaderSize
|
||||
DOC_START
|
||||
- This specifies the maximum size for HTTP headers in a reply.
|
||||
- Reply headers are usually relatively small (about 512 bytes).
|
||||
- Placing a limit on the reply header size will catch certain
|
||||
- bugs (for example with persistent connections) and possibly
|
||||
- buffer-overflow or denial-of-service attacks.
|
||||
+ This directives limits the header size of a received HTTP response
|
||||
+ (including status-line). Increasing this limit beyond its 64 KB default
|
||||
+ exposes certain old Squid code to various denial-of-service attacks. This
|
||||
+ limit also applies to FTP command responses.
|
||||
+
|
||||
+ Squid also checks this limit when loading hit responses from disk cache.
|
||||
+
|
||||
+ Squid does not check this limit when sending responses.
|
||||
DOC_END
|
||||
|
||||
NAME: request_body_max_size
|
||||
diff --git a/src/http.cc b/src/http.cc
|
||||
index 7c9ae70..98e3969 100644
|
||||
--- a/src/http.cc
|
||||
+++ b/src/http.cc
|
||||
@@ -1926,8 +1926,9 @@ HttpStateData::httpBuildRequestHeader(HttpRequest * request,
|
||||
|
||||
String strFwd = hdr_in->getList(Http::HdrType::X_FORWARDED_FOR);
|
||||
|
||||
- // if we cannot double strFwd size, then it grew past 50% of the limit
|
||||
- if (!strFwd.canGrowBy(strFwd.size())) {
|
||||
+ // Detect unreasonably long header values. And paranoidly check String
|
||||
+ // limits: a String ought to accommodate two reasonable-length values.
|
||||
+ if (strFwd.size() > 32*1024 || !strFwd.canGrowBy(strFwd.size())) {
|
||||
// There is probably a forwarding loop with Via detection disabled.
|
||||
// If we do nothing, String will assert on overflow soon.
|
||||
// TODO: Terminate all transactions with huge XFF?
|
Loading…
Reference in new issue