Sanitize HTML in Markdown sections

Author: sauls8t

domain/section/markdown/markdown.go

@@ -18,6 +18,7 @@ import (
 	"github.com/documize/community/core/env"
 	"github.com/documize/community/domain/section/provider"
 	"github.com/documize/community/domain/store"
+	"github.com/microcosm-cc/bluemonday"
 )
 
 // Provider represents Markdown
@@ -47,9 +48,11 @@ func (*Provider) Command(ctx *provider.Context, w http.ResponseWriter, r *http.R
 
 // Render converts markdown data into HTML suitable for browser rendering.
 func (*Provider) Render(ctx *provider.Context, config, data string) string {
-	result := blackfriday.Run([]byte(data))
+	unsafe := blackfriday.Run([]byte(data))
 
-	return string(result)
+	safe := bluemonday.UGCPolicy().SanitizeBytes(unsafe)
+
+	return string(safe)
 }
 
 // Refresh just sends back data as-is.

go.mod

@@ -23,6 +23,7 @@ require (
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/lib/pq v1.2.0
 	github.com/mb0/diff v0.0.0-20131118162322-d8d9a906c24d // indirect
+	github.com/microcosm-cc/bluemonday v1.0.2
 	github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d
 	github.com/pkg/errors v0.8.0
 	github.com/rainycape/unidecode v0.0.0-20150907023854-cb7f23ec59be // indirect

go.sum

@@ -94,6 +94,8 @@ github.com/mattn/go-sqlite3 v1.9.0/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOq
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/mb0/diff v0.0.0-20131118162322-d8d9a906c24d h1:eAS2t2Vy+6psf9LZ4T5WXWsbkBt3Tu5PWekJy5AGyEU=
 github.com/mb0/diff v0.0.0-20131118162322-d8d9a906c24d/go.mod h1:3YMHqrw2Qu3Liy82v4QdAG17e9k91HZ7w3hqlpWqhDo=
+github.com/microcosm-cc/bluemonday v1.0.2 h1:5lPfLTTAvAbtS0VqT+94yOtFnGfUWYyx0+iToC3Os3s=
+github.com/microcosm-cc/bluemonday v1.0.2/go.mod h1:iVP4YcDBq+n/5fb23BhYFvIMq/leAFZyRl6bYmGDlGc=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d h1:VhgPp6v9qf9Agr/56bj7Y/xa04UccTW04VP0Qed4vnQ=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d/go.mod h1:YUTz3bUH2ZwIWBy3CJBeOBEugqcmXREj14T+iG/4k4U=
@@ -137,6 +139,7 @@ golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73r
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20181220203305-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190125091013-d26f9f9a57f3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=