MM-25006: Fix occurences of unclosed http bodies (#14521)

* MM-25006: Fix occurences of unclosed http bodies

And while here, we also use ioutil.Discard to read the remaining
body instead of reading with ioutil.ReadAll which allocates a separate
byte buffer.

* Fix mistake

* Address review comments

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

api4/system.go

@@ -6,6 +6,8 @@ package api4
 import (
 	"encoding/json"
 	"fmt"
+	"io"
+	"io/ioutil"
 	"net/http"
 	"runtime"
 	"strconv"
@@ -432,6 +434,10 @@ func getRedirectLocation(c *Context, w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte(model.MapToJson(m)))
 		return
 	}
+	defer func() {
+		io.Copy(ioutil.Discard, res.Body)
+		res.Body.Close()
+	}()
 
 	location := res.Header.Get("Location")
 	redirectLocationDataCache.AddWithExpiresInSecs(url, location, 3600) // Expires after 1 hour

app/admin.go

@@ -6,6 +6,7 @@ package app
 import (
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
 	"time"
 
@@ -177,6 +178,10 @@ func (a *App) TestSiteURL(siteURL string) *model.AppError {
 	if err != nil || res.StatusCode != 200 {
 		return model.NewAppError("testSiteURL", "app.admin.test_site_url.failure", nil, "", http.StatusBadRequest)
 	}
+	defer func() {
+		_, _ = io.Copy(ioutil.Discard, res.Body)
+		_ = res.Body.Close()
+	}()
 
 	return nil
 }

app/command_loadtest.go

@@ -5,6 +5,7 @@ package app
 
 import (
 	"io"
+	"io/ioutil"
 	"net/http"
 	"path"
 	"regexp"
@@ -472,20 +473,24 @@ func (me *LoadTestProvider) UrlCommand(a *App, args *model.CommandArgs, message
 		}
 	}
 
-	var contents io.ReadCloser
-	if r, err := http.Get(url); err != nil {
+	r, err := http.Get(url)
+	if err != nil {
 		return &model.CommandResponse{Text: "Unable to get file", ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}, err
-	} else if r.StatusCode > 400 {
+	}
+	defer func() {
+		io.Copy(ioutil.Discard, r.Body)
+		r.Body.Close()
+	}()
+
+	if r.StatusCode > 400 {
 		return &model.CommandResponse{Text: "Unable to get file", ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}, errors.Errorf("unexpected status code %d", r.StatusCode)
-	} else {
-		contents = r.Body
 	}
 
 	bytes := make([]byte, 4000)
 
 	// break contents into 4000 byte posts
 	for {
-		length, err := contents.Read(bytes)
+		length, err := r.Body.Read(bytes)
 		if err != nil && err != io.EOF {
 			return &model.CommandResponse{Text: "Encountered error reading file", ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}, err
 		}
@@ -522,16 +527,20 @@ func (me *LoadTestProvider) JsonCommand(a *App, args *model.CommandArgs, message
 		}
 	}
 
-	var contents io.ReadCloser
-	if r, err := http.Get(url); err != nil {
+	r, err := http.Get(url)
+	if err != nil {
 		return &model.CommandResponse{Text: "Unable to get file", ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}, err
-	} else if r.StatusCode > 400 {
-		return &model.CommandResponse{Text: "Unable to get file", ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}, errors.Errorf("unexpected status code %d", r.StatusCode)
-	} else {
-		contents = r.Body
 	}
 
-	post := model.PostFromJson(contents)
+	if r.StatusCode > 400 {
+		return &model.CommandResponse{Text: "Unable to get file", ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL}, errors.Errorf("unexpected status code %d", r.StatusCode)
+	}
+	defer func() {
+		io.Copy(ioutil.Discard, r.Body)
+		r.Body.Close()
+	}()
+
+	post := model.PostFromJson(r.Body)
 	post.ChannelId = args.ChannelId
 	post.UserId = args.UserId
 	if post.Message == "" {

app/post_metadata.go

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"image"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -402,7 +403,10 @@ func (a *App) getLinkMetadata(requestURL string, timestamp int64, isNewPost bool
 	}
 
 	if body != nil {
-		defer body.Close()
+		defer func() {
+			io.Copy(ioutil.Discard, body)
+			body.Close()
+		}()
 	}
 
 	if err == nil {

app/security_update_check.go

@@ -106,7 +106,7 @@ func (s *Server) DoSecurityUpdateCheck() {
 					}
 
 					body, err := ioutil.ReadAll(resBody.Body)
-					res.Body.Close()
+					resBody.Body.Close()
 					if err != nil || resBody.StatusCode != 200 {
 						mlog.Error("Failed to read security bulletin details")
 						return

model/client4.go

@@ -65,7 +65,7 @@ type Client4 struct {
 
 func closeBody(r *http.Response) {
 	if r.Body != nil {
-		_, _ = ioutil.ReadAll(r.Body)
+		_, _ = io.Copy(ioutil.Discard, r.Body)
 		_ = r.Body.Close()
 	}
 }

services/marketplace/client.go

@@ -5,6 +5,7 @@ package marketplace
 
 import (
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"net/url"
@@ -79,7 +80,7 @@ func (c *Client) GetPlugin(filter *model.MarketplacePluginFilter, pluginVersion
 // closeBody ensures the Body of an http.Response is properly closed.
 func closeBody(r *http.Response) {
 	if r.Body != nil {
-		_, _ = ioutil.ReadAll(r.Body)
+		_, _ = io.Copy(ioutil.Discard, r.Body)
 		_ = r.Body.Close()
 	}
 }