From 4b6b3b765b4cf0eab016841707dc03cc802a836c Mon Sep 17 00:00:00 2001
From: Emmanuel T Odeke <emmanuel@orijtech.com>
Date: Thu, 23 Jun 2022 21:35:38 -0700
Subject: [PATCH] fix: store/streaming/file: fix os.File leaks in
 (*StreamService).Listen* methods (#12339)

This change fixes resource leaks that were present due a rigid
error return path and didn't invoke .Close until the last line
of each method. This change fixes the problem by using a named
return error variable and if the return error value is nil, we
derive its final value from the unconditionally defer os.File.Close
value, which matches the prior logic but now fixes the flaw.

Fixes #12336
Fixes #12337
Fixes #12338
---
 store/streaming/file/service.go | 48 ++++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/store/streaming/file/service.go b/store/streaming/file/service.go
index 28e77a52fa..dd97ec4dea 100644
--- a/store/streaming/file/service.go
+++ b/store/streaming/file/service.go
@@ -88,12 +88,19 @@ func (fss *StreamingService) Listeners() map[types.StoreKey][]types.WriteListene
 // ListenBeginBlock satisfies the baseapp.ABCIListener interface
 // It writes the received BeginBlock request and response and the resulting state changes
 // out to a file as described in the above the naming schema
-func (fss *StreamingService) ListenBeginBlock(ctx sdk.Context, req abci.RequestBeginBlock, res abci.ResponseBeginBlock) error {
+func (fss *StreamingService) ListenBeginBlock(ctx sdk.Context, req abci.RequestBeginBlock, res abci.ResponseBeginBlock) (rerr error) {
 	// generate the new file
 	dstFile, err := fss.openBeginBlockFile(req)
 	if err != nil {
 		return err
 	}
+	defer func() {
+		cerr := dstFile.Close()
+		if rerr == nil {
+			rerr = cerr
+		}
+	}()
+
 	// write req to file
 	lengthPrefixedReqBytes, err := fss.codec.MarshalLengthPrefixed(&req)
 	if err != nil {
@@ -119,11 +126,8 @@ func (fss *StreamingService) ListenBeginBlock(ctx sdk.Context, req abci.RequestB
 	if err != nil {
 		return err
 	}
-	if _, err = dstFile.Write(lengthPrefixedResBytes); err != nil {
-		return err
-	}
-	// close file
-	return dstFile.Close()
+	_, err = dstFile.Write(lengthPrefixedResBytes)
+	return err
 }
 
 func (fss *StreamingService) openBeginBlockFile(req abci.RequestBeginBlock) (*os.File, error) {
@@ -139,12 +143,19 @@ func (fss *StreamingService) openBeginBlockFile(req abci.RequestBeginBlock) (*os
 // ListenDeliverTx satisfies the baseapp.ABCIListener interface
 // It writes the received DeliverTx request and response and the resulting state changes
 // out to a file as described in the above the naming schema
-func (fss *StreamingService) ListenDeliverTx(ctx sdk.Context, req abci.RequestDeliverTx, res abci.ResponseDeliverTx) error {
+func (fss *StreamingService) ListenDeliverTx(ctx sdk.Context, req abci.RequestDeliverTx, res abci.ResponseDeliverTx) (rerr error) {
 	// generate the new file
 	dstFile, err := fss.openDeliverTxFile()
 	if err != nil {
 		return err
 	}
+	defer func() {
+		cerr := dstFile.Close()
+		if rerr == nil {
+			rerr = cerr
+		}
+	}()
+
 	// write req to file
 	lengthPrefixedReqBytes, err := fss.codec.MarshalLengthPrefixed(&req)
 	if err != nil {
@@ -170,11 +181,8 @@ func (fss *StreamingService) ListenDeliverTx(ctx sdk.Context, req abci.RequestDe
 	if err != nil {
 		return err
 	}
-	if _, err = dstFile.Write(lengthPrefixedResBytes); err != nil {
-		return err
-	}
-	// close file
-	return dstFile.Close()
+	_, err = dstFile.Write(lengthPrefixedResBytes)
+	return err
 }
 
 func (fss *StreamingService) openDeliverTxFile() (*os.File, error) {
@@ -189,12 +197,19 @@ func (fss *StreamingService) openDeliverTxFile() (*os.File, error) {
 // ListenEndBlock satisfies the baseapp.ABCIListener interface
 // It writes the received EndBlock request and response and the resulting state changes
 // out to a file as described in the above the naming schema
-func (fss *StreamingService) ListenEndBlock(ctx sdk.Context, req abci.RequestEndBlock, res abci.ResponseEndBlock) error {
+func (fss *StreamingService) ListenEndBlock(ctx sdk.Context, req abci.RequestEndBlock, res abci.ResponseEndBlock) (rerr error) {
 	// generate the new file
 	dstFile, err := fss.openEndBlockFile()
 	if err != nil {
 		return err
 	}
+	defer func() {
+		cerr := dstFile.Close()
+		if rerr == nil {
+			rerr = cerr
+		}
+	}()
+
 	// write req to file
 	lengthPrefixedReqBytes, err := fss.codec.MarshalLengthPrefixed(&req)
 	if err != nil {
@@ -220,11 +235,8 @@ func (fss *StreamingService) ListenEndBlock(ctx sdk.Context, req abci.RequestEnd
 	if err != nil {
 		return err
 	}
-	if _, err = dstFile.Write(lengthPrefixedResBytes); err != nil {
-		return err
-	}
-	// close file
-	return dstFile.Close()
+	_, err = dstFile.Write(lengthPrefixedResBytes)
+	return err
 }
 
 func (fss *StreamingService) openEndBlockFile() (*os.File, error) {