File 0278-ssl-Fix-function-merge_fragments-2.patch of Package erlang
From a8647551313659209965e49dd6e672cfef3f1a40 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Dimitrov?= <peterdmv@erlang.org>
Date: Tue, 9 Apr 2019 09:51:14 +0200
Subject: [PATCH 2/4] ssl: Fix function merge_fragments/2
Change-Id: Icc99d5f3b8c667107926603e9d546d7198bd098d
---
lib/ssl/src/dtls_handshake.erl | 153 ++++++++++++++++++++++++++++-------------
1 file changed, 107 insertions(+), 46 deletions(-)
diff --git a/lib/ssl/src/dtls_handshake.erl b/lib/ssl/src/dtls_handshake.erl
index 46e8348ce0..0a0c6f0c2e 100644
--- a/lib/ssl/src/dtls_handshake.erl
+++ b/lib/ssl/src/dtls_handshake.erl
@@ -427,74 +427,135 @@ merge_fragment(Frag0, [Frag1 | Rest]) ->
Frag ->
merge_fragment(Frag, Rest)
end.
-%% Duplicate
+
+
+%% Duplicate (fully contained fragment)
+%% 2,5 _ _ P P P P P
+%% 2,5 _ _ C C C C C
merge_fragments(#handshake_fragment{
- fragment_offset = PreviousOffSet,
+ fragment_offset = PreviousOffSet,
fragment_length = PreviousLen,
fragment = PreviousData
- } = Previous,
+ } = Previous,
#handshake_fragment{
fragment_offset = PreviousOffSet,
fragment_length = PreviousLen,
fragment = PreviousData}) ->
Previous;
-%% Lager fragment save new data
+%% Duplicate (fully contained fragment)
+%% 2,5 _ _ P P P P P
+%% 2,2 _ _ C C
+%% 0,3 X X X
+%% 5,3 _ _ _ _ _ X X X
merge_fragments(#handshake_fragment{
- fragment_offset = PreviousOffSet,
- fragment_length = PreviousLen,
+ fragment_offset = PreviousOffset,
+ fragment_length = PreviousLen
+ } = Previous,
+ #handshake_fragment{
+ fragment_offset = CurrentOffset,
+ fragment_length = CurrentLen})
+ when PreviousOffset =< CurrentOffset andalso
+ CurrentOffset =< PreviousOffset + PreviousLen andalso
+ CurrentOffset + CurrentLen =< PreviousOffset + PreviousLen ->
+ Previous;
+
+%% Fully overlapping fragments
+%% 2,5 _ _ P P P P P
+%% 0,8 C C C C C C C C
+merge_fragments(#handshake_fragment{
+ fragment_offset = PreviousOffset,
+ fragment_length = PreviousLen
+ },
+ #handshake_fragment{
+ fragment_offset = CurrentOffset,
+ fragment_length = CurrentLen} = Current)
+ when CurrentOffset =< PreviousOffset andalso
+ CurrentOffset + CurrentLen >= PreviousOffset + PreviousLen ->
+ Current;
+
+%% Overlapping fragments
+%% 2,5 _ _ P P P P P
+%% 0,3 C C C
+merge_fragments(#handshake_fragment{
+ fragment_offset = PreviousOffset,
+ fragment_length = PreviousLen,
fragment = PreviousData
- } = Previous,
- #handshake_fragment{
- fragment_offset = PreviousOffSet,
- fragment_length = CurrentLen,
- fragment = CurrentData}) when CurrentLen > PreviousLen ->
- NewLength = CurrentLen - PreviousLen,
- <<_:PreviousLen/binary, NewData/binary>> = CurrentData,
+ } = Previous,
+ #handshake_fragment{
+ fragment_offset = CurrentOffset,
+ fragment_length = CurrentLen,
+ fragment = CurrentData})
+ when CurrentOffset < PreviousOffset andalso
+ CurrentOffset + CurrentLen < PreviousOffset + PreviousLen ->
+ NewDataLen = PreviousOffset - CurrentOffset,
+ <<NewData:NewDataLen/binary, _/binary>> = CurrentData,
Previous#handshake_fragment{
- fragment_length = PreviousLen + NewLength,
- fragment = <<PreviousData/binary, NewData/binary>>
+ fragment_length = PreviousLen + NewDataLen,
+ fragment = <<NewData/binary, PreviousData/binary>>
};
-%% Smaller fragment
+%% Overlapping fragments
+%% 2,5 _ _ P P P P P
+%% 5,3 _ _ _ _ _ C C C
merge_fragments(#handshake_fragment{
- fragment_offset = PreviousOffSet,
- fragment_length = PreviousLen
- } = Previous,
- #handshake_fragment{
- fragment_offset = PreviousOffSet,
- fragment_length = CurrentLen}) when CurrentLen < PreviousLen ->
- Previous;
-%% Next fragment, might be overlapping
+ fragment_offset = PreviousOffset,
+ fragment_length = PreviousLen,
+ fragment = PreviousData
+ } = Previous,
+ #handshake_fragment{
+ fragment_offset = CurrentOffset,
+ fragment_length = CurrentLen,
+ fragment = CurrentData})
+ when CurrentOffset > PreviousOffset andalso
+ CurrentOffset < PreviousOffset + PreviousLen ->
+ NewDataLen = CurrentOffset + CurrentLen - (PreviousOffset + PreviousLen),
+ DropLen = CurrentLen - NewDataLen,
+ <<_:DropLen/binary, NewData/binary>> = CurrentData,
+ Previous#handshake_fragment{
+ fragment_length = PreviousLen + NewDataLen,
+ fragment = <<PreviousData/binary, NewData/binary>>
+ };
+
+%% Adjacent fragments
+%% 2,5 _ _ P P P P P
+%% 7,3 _ _ _ _ _ _ _ C C C
merge_fragments(#handshake_fragment{
- fragment_offset = PreviousOffSet,
- fragment_length = PreviousLen,
+ fragment_offset = PreviousOffset,
+ fragment_length = PreviousLen,
fragment = PreviousData
- } = Previous,
- #handshake_fragment{
- fragment_offset = CurrentOffSet,
- fragment_length = CurrentLen,
- fragment = CurrentData})
- when PreviousOffSet + PreviousLen >= CurrentOffSet andalso
- PreviousOffSet + PreviousLen < CurrentOffSet + CurrentLen ->
- CurrentStart = PreviousOffSet + PreviousLen - CurrentOffSet,
- <<_:CurrentStart/bytes, Data/binary>> = CurrentData,
+ } = Previous,
+ #handshake_fragment{
+ fragment_offset = CurrentOffset,
+ fragment_length = CurrentLen,
+ fragment = CurrentData})
+ when CurrentOffset =:= PreviousOffset + PreviousLen ->
Previous#handshake_fragment{
- fragment_length = PreviousLen + CurrentLen - CurrentStart,
- fragment = <<PreviousData/binary, Data/binary>>};
-%% already fully contained fragment
+ fragment_length = PreviousLen + CurrentLen,
+ fragment = <<PreviousData/binary, CurrentData/binary>>
+ };
+
+%% Adjacent fragments
+%% 2,5 _ _ P P P P P
+%% 0,2 C C
merge_fragments(#handshake_fragment{
- fragment_offset = PreviousOffSet,
- fragment_length = PreviousLen
- } = Previous,
+ fragment_offset = PreviousOffset,
+ fragment_length = PreviousLen,
+ fragment = PreviousData
+ } = Previous,
#handshake_fragment{
- fragment_offset = CurrentOffSet,
- fragment_length = CurrentLen})
- when PreviousOffSet + PreviousLen >= CurrentOffSet andalso
- PreviousOffSet + PreviousLen >= CurrentOffSet + CurrentLen ->
- Previous;
+ fragment_offset = CurrentOffset,
+ fragment_length = CurrentLen,
+ fragment = CurrentData})
+ when PreviousOffset =:= CurrentOffset + CurrentLen ->
+ Previous#handshake_fragment{
+ fragment_length = PreviousLen + CurrentLen,
+ fragment = <<CurrentData/binary, PreviousData/binary>>
+ };
%% No merge there is a gap
+%% 3,5 _ _ _ P P P P
+%% 0,2 C C
merge_fragments(Previous, Current) ->
[Previous, Current].
--
2.16.4
