From 0d27d3e0a6815575fca422f946e258bf20452502 Mon Sep 17 00:00:00 2001
From: Jan Lehnardt <jan@apache.org>
Date: Sat, 3 Mar 2018 15:00:42 +0100
Subject: [PATCH] feat: allow configuration of maximum number of attachments
 per doc

---
 src/chttpd/src/chttpd_db.erl |  1 +
 src/couch/src/couch_att.erl  | 22 +++++++++++++++++++++-
 src/couch/src/couch_doc.erl  |  4 ++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/chttpd/src/chttpd_db.erl b/src/chttpd/src/chttpd_db.erl
index 2c3ec635679..cae1c11a14f 100644
--- a/src/chttpd/src/chttpd_db.erl
+++ b/src/chttpd/src/chttpd_db.erl
@@ -1266,6 +1266,7 @@ db_attachment_req(#httpd{method=Method, user_ctx=Ctx}=Req, Db, DocId, FileNamePa
     DocEdited = Doc#doc{
         atts = NewAtt ++ [A || A <- Atts, couch_att:fetch(name, A) /= FileName]
     },
+    couch_att:validate_attachment_count(length(DocEdited#doc.atts)),
     W = chttpd:qs_value(Req, "w", integer_to_list(mem3:quorum(Db))),
     case fabric:update_doc(Db, DocEdited, [{user_ctx,Ctx}, {w,W}]) of
     {ok, UpdatedRev} ->
diff --git a/src/couch/src/couch_att.erl b/src/couch/src/couch_att.erl
index d699b6a8fc6..fa45b932dd4 100644
--- a/src/couch/src/couch_att.erl
+++ b/src/couch/src/couch_att.erl
@@ -52,7 +52,8 @@
 
 -export([
     max_attachment_size/0,
-    validate_attachment_size/3
+    validate_attachment_size/3,
+    validate_attachment_count/1
 ]).
 
 -compile(nowarn_deprecated_type).
@@ -718,6 +719,25 @@ max_attachment_size() ->
     end.
 
 
+max_attachment_count() ->
+    case config:get("couchdb", "max_attachments_per_document", "infinity") of
+        "infinity" ->
+            infinity;
+        MaxAttSize ->
+            list_to_integer(MaxAttSize)
+    end.
+
+
+validate_attachment_count(AttCount) ->
+    case max_attachment_count() of
+        infinity -> ok;
+        MaxAttCount when AttCount =< MaxAttCount -> ok;
+        _TooManyAttachments ->
+            throw({request_entity_too_large,
+                <<"hit max_attachments_per_document">>})
+    end.
+
+
 validate_attachment_size(AttName, AttSize, MaxAttSize)
         when is_integer(AttSize),  AttSize > MaxAttSize ->
     throw({request_entity_too_large, {attachment, AttName}});
diff --git a/src/couch/src/couch_doc.erl b/src/couch/src/couch_doc.erl
index f960ec5c2d9..a39ff1752f0 100644
--- a/src/couch/src/couch_doc.erl
+++ b/src/couch/src/couch_doc.erl
@@ -135,6 +135,7 @@ from_json_obj_validate(EJson, DbName) ->
     Doc = from_json_obj(EJson, DbName),
     case couch_ejson_size:encoded_size(Doc#doc.body) =< MaxSize of
         true ->
+             validate_attachment_count(Doc#doc.atts),
              validate_attachment_sizes(Doc#doc.atts),
              Doc;
         false ->
@@ -153,6 +154,9 @@ validate_attachment_sizes(Atts) ->
     end, Atts).
 
 
+validate_attachment_count(Atts) ->
+    couch_att:validate_attachment_count(length(Atts)).
+
 from_json_obj({Props}) ->
     from_json_obj({Props}, undefined).