From 22ea1954a30c388f5a0ae3fa56b0fc6c2ff069e8 Mon Sep 17 00:00:00 2001
From: chengyechun <chengyechun1@huawei.com>
Date: Mon, 11 Nov 2024 14:39:33 +0800
Subject: [PATCH] fix sftp too many out of order packets

---
 ...x-sftp-too-many-out-of-order-packets.patch | 75 +++++++++++++++++++
 lftp.spec                                     |  9 ++-
 2 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 backport-fix-sftp-too-many-out-of-order-packets.patch

diff --git a/backport-fix-sftp-too-many-out-of-order-packets.patch b/backport-fix-sftp-too-many-out-of-order-packets.patch
new file mode 100644
index 0000000..646c892
--- /dev/null
+++ b/backport-fix-sftp-too-many-out-of-order-packets.patch
@@ -0,0 +1,75 @@
+From fdb81537a2f854cf5e2b9dd95c7e5542bb5cd420 Mon Sep 17 00:00:00 2001
+From: Paul Dennis <padenn@github.com>
+Date: Mon, 29 Jul 2024 16:43:02 -0400
+Subject: [PATCH] Attempt to fix SFTP issue #636 Too many out-of-order packets.
+
+lftp supports making many SFTP DATA requests in parallel when downloading a file. Responses
+with data payloads from an sftp server can sometimes arrive in a different order from the
+original requests.
+
+The out of order data payload (packets) are added to the `ooo_chain` to be processed when the expected
+(but late) next requested packet arrives.
+
+A single packet being delayed while many parallel requests continue to be made can sometimes result in the
+`Too many out-of-order packets` message if the `ooo_chain` buffer of 64 entries is exceeded.
+
+This fix checks the remaining capacity of the `ooo_chain` and pending requests (`RespQueueSize()`)
+and will avoid sending new requests for more data until the `ooo_chain` is processed or `RespQueueSize()`
+shrinks. Adding this constraint does mean that `sftp:max-packets-in-flight` will be limited to
+the current `ooo_chain` length of 64.
+
+I was able to reliably reproduce the issue with a 4gb download and verify the fix.
+
+Conflict:NA
+Reference:https://github/lavv17/lftp/commit/fdb81537a2f854cf5e2b9dd95c7e5542bb5cd420
+
+---
+ src/SFtp.cc | 8 ++++++--
+ src/SFtp.h  | 1 +
+ 2 files changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/src/SFtp.cc b/src/SFtp.cc
+index 6c818dfa1..5879a6314 100644
+--- a/src/SFtp.cc
++++ b/src/SFtp.cc
+@@ -344,6 +344,7 @@ void SFtp::Init()
+    size_write=0x8000;
+    use_full_path=false;
+    flush_timer.Set(0,500);
++   max_out_of_order=64;
+ }
+ 
+ SFtp::SFtp() : SSH_Access("SFTP:")
+@@ -892,7 +893,7 @@ void SFtp::HandleExpect(Expect *e)
+ 	 {
+ 	    LogNote(9,"put a packet with id=%d on out-of-order chain (need_pos=%lld packet_pos=%lld)",
+ 	       reply->GetID(),(long long)(pos+file_buf->Size()),(long long)r->pos);
+-	    if(ooo_chain.count()>=64)
++	    if(ooo_chain.count()>=max_out_of_order)
+ 	    {
+ 	       LogError(0,"Too many out-of-order packets");
+ 	       Disconnect();
+@@ -1192,7 +1193,10 @@ int SFtp::Read(Buffer *buf,int size)
+    {
+       // keep some packets in flight.
+       int limit=(entity_size>=0?max_packets_in_flight:max_packets_in_flight_slow_start);
+-      if(RespQueueSize()<limit && !file_buf->Eof())
++      int ooo_queue_available=max_out_of_order-ooo_chain.count();
++      int current_in_flight=RespQueueSize();
++      if(RespQueueSize()<limit && !file_buf->Eof()
++         && current_in_flight < ooo_queue_available)
+       {
+ 	 // but don't request much after possible EOF.
+ 	 if(entity_size<0 || request_pos<entity_size || RespQueueSize()<2)
+diff --git a/src/SFtp.h b/src/SFtp.h
+index 50888b376..2099440c6 100644
+--- a/src/SFtp.h
++++ b/src/SFtp.h
+@@ -755,6 +755,7 @@ enum sftp_status_t {
+    int size_read;
+    int size_write;
+    bool use_full_path;
++   int max_out_of_order;
+ 
+ protected:
+    void SetError(int code,const Packet *reply);
diff --git a/lftp.spec b/lftp.spec
index 35ee89a..004c49a 100644
--- a/lftp.spec
+++ b/lftp.spec
@@ -1,7 +1,7 @@
 Summary:	A sophisticated file transfer program
 Name:		lftp
 Version:	4.9.2
-Release:	5
+Release:	6
 License:	GPLv3+
 URL:		http://lftp.yar.ru/
 Source0:        http://lftp.yar.ru/ftp/%{name}-%{version}.tar.xz
@@ -16,6 +16,7 @@ Patch6001:      backport-fix-a-null-deref-on-exit.patch
 Patch6002:      backport-Quit-while-source-file-increased.patch
 Patch6003:      backport-Ensure-that-PollVec-enum-matches-poll-values.patch
 Patch6004:      backport-fix-second-find_cmd-Segmentation-fault.patch
+Patch6005:      backport-fix-sftp-too-many-out-of-order-packets.patch
 
 %description
 LFTP is a sophisticated file transfer program supporting a number of
@@ -89,6 +90,12 @@ echo "%{_libdir}/lftp/%{version}" > %{buildroot}/etc/ld.so.conf.d/%{name}-%{_arc
 
 
 %changelog
+* Mon Nov 11 2024 chengyechun <chengyechun1@huawei.com> - 4.9.2-6
+- Type:bugfix
+- CVE:NA
+- SUG:NA
+- DESC:fix sftp too many out of order packets
+
 * Fri Aug 02 2024 chengyechun <chengyechun1@huawei.com> - 4.9.2-5
 - Type:bugfix
 - CVE:NA