Include file extension checks in attachment API (#32151)

From testing, I found that issue posters and users with repository write
access are able to edit attachment names in a way that circumvents the
instance-level file extension restrictions using the edit attachment
APIs. This snapshot adds checks for these endpoints.
This commit is contained in:
Kemal Zebari 2024-11-06 13:34:32 -08:00 committed by GitHub
parent f64fbd9b74
commit 7adc4717ec
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
9 changed files with 148 additions and 17 deletions

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@ -12,7 +12,7 @@ import (
"code.gitea.io/gitea/modules/setting"
api "code.gitea.io/gitea/modules/structs"
"code.gitea.io/gitea/modules/web"
"code.gitea.io/gitea/services/attachment"
attachment_service "code.gitea.io/gitea/services/attachment"
"code.gitea.io/gitea/services/context"
"code.gitea.io/gitea/services/context/upload"
"code.gitea.io/gitea/services/convert"
@ -181,7 +181,7 @@ func CreateIssueAttachment(ctx *context.APIContext) {
filename = query
}
attachment, err := attachment.UploadAttachment(ctx, file, setting.Attachment.AllowedTypes, header.Size, &repo_model.Attachment{
attachment, err := attachment_service.UploadAttachment(ctx, file, setting.Attachment.AllowedTypes, header.Size, &repo_model.Attachment{
Name: filename,
UploaderID: ctx.Doer.ID,
RepoID: ctx.Repo.Repository.ID,
@ -247,6 +247,8 @@ func EditIssueAttachment(ctx *context.APIContext) {
// "$ref": "#/responses/Attachment"
// "404":
// "$ref": "#/responses/error"
// "422":
// "$ref": "#/responses/validationError"
// "423":
// "$ref": "#/responses/repoArchivedError"
@ -261,8 +263,13 @@ func EditIssueAttachment(ctx *context.APIContext) {
attachment.Name = form.Name
}
if err := repo_model.UpdateAttachment(ctx, attachment); err != nil {
if err := attachment_service.UpdateAttachment(ctx, setting.Attachment.AllowedTypes, attachment); err != nil {
if upload.IsErrFileTypeForbidden(err) {
ctx.Error(http.StatusUnprocessableEntity, "", err)
return
}
ctx.Error(http.StatusInternalServerError, "UpdateAttachment", err)
return
}
ctx.JSON(http.StatusCreated, convert.ToAPIAttachment(ctx.Repo.Repository, attachment))

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@ -14,7 +14,7 @@ import (
"code.gitea.io/gitea/modules/setting"
api "code.gitea.io/gitea/modules/structs"
"code.gitea.io/gitea/modules/web"
"code.gitea.io/gitea/services/attachment"
attachment_service "code.gitea.io/gitea/services/attachment"
"code.gitea.io/gitea/services/context"
"code.gitea.io/gitea/services/context/upload"
"code.gitea.io/gitea/services/convert"
@ -189,7 +189,7 @@ func CreateIssueCommentAttachment(ctx *context.APIContext) {
filename = query
}
attachment, err := attachment.UploadAttachment(ctx, file, setting.Attachment.AllowedTypes, header.Size, &repo_model.Attachment{
attachment, err := attachment_service.UploadAttachment(ctx, file, setting.Attachment.AllowedTypes, header.Size, &repo_model.Attachment{
Name: filename,
UploaderID: ctx.Doer.ID,
RepoID: ctx.Repo.Repository.ID,
@ -263,6 +263,8 @@ func EditIssueCommentAttachment(ctx *context.APIContext) {
// "$ref": "#/responses/Attachment"
// "404":
// "$ref": "#/responses/error"
// "422":
// "$ref": "#/responses/validationError"
// "423":
// "$ref": "#/responses/repoArchivedError"
attach := getIssueCommentAttachmentSafeWrite(ctx)
@ -275,8 +277,13 @@ func EditIssueCommentAttachment(ctx *context.APIContext) {
attach.Name = form.Name
}
if err := repo_model.UpdateAttachment(ctx, attach); err != nil {
if err := attachment_service.UpdateAttachment(ctx, setting.Attachment.AllowedTypes, attach); err != nil {
if upload.IsErrFileTypeForbidden(err) {
ctx.Error(http.StatusUnprocessableEntity, "", err)
return
}
ctx.Error(http.StatusInternalServerError, "UpdateAttachment", attach)
return
}
ctx.JSON(http.StatusCreated, convert.ToAPIAttachment(ctx.Repo.Repository, attach))
}

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@ -13,7 +13,7 @@ import (
"code.gitea.io/gitea/modules/setting"
api "code.gitea.io/gitea/modules/structs"
"code.gitea.io/gitea/modules/web"
"code.gitea.io/gitea/services/attachment"
attachment_service "code.gitea.io/gitea/services/attachment"
"code.gitea.io/gitea/services/context"
"code.gitea.io/gitea/services/context/upload"
"code.gitea.io/gitea/services/convert"
@ -234,7 +234,7 @@ func CreateReleaseAttachment(ctx *context.APIContext) {
}
// Create a new attachment and save the file
attach, err := attachment.UploadAttachment(ctx, content, setting.Repository.Release.AllowedTypes, size, &repo_model.Attachment{
attach, err := attachment_service.UploadAttachment(ctx, content, setting.Repository.Release.AllowedTypes, size, &repo_model.Attachment{
Name: filename,
UploaderID: ctx.Doer.ID,
RepoID: ctx.Repo.Repository.ID,
@ -291,6 +291,8 @@ func EditReleaseAttachment(ctx *context.APIContext) {
// responses:
// "201":
// "$ref": "#/responses/Attachment"
// "422":
// "$ref": "#/responses/validationError"
// "404":
// "$ref": "#/responses/notFound"
@ -322,8 +324,13 @@ func EditReleaseAttachment(ctx *context.APIContext) {
attach.Name = form.Name
}
if err := repo_model.UpdateAttachment(ctx, attach); err != nil {
if err := attachment_service.UpdateAttachment(ctx, setting.Repository.Release.AllowedTypes, attach); err != nil {
if upload.IsErrFileTypeForbidden(err) {
ctx.Error(http.StatusUnprocessableEntity, "", err)
return
}
ctx.Error(http.StatusInternalServerError, "UpdateAttachment", attach)
return
}
ctx.JSON(http.StatusCreated, convert.ToAPIAttachment(ctx.Repo.Repository, attach))
}

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@ -50,3 +50,12 @@ func UploadAttachment(ctx context.Context, file io.Reader, allowedTypes string,
return NewAttachment(ctx, attach, io.MultiReader(bytes.NewReader(buf), file), fileSize)
}
// UpdateAttachment updates an attachment, verifying that its name is among the allowed types.
func UpdateAttachment(ctx context.Context, allowedTypes string, attach *repo_model.Attachment) error {
if err := upload.Verify(nil, attach.Name, allowedTypes); err != nil {
return err
}
return repo_model.UpdateAttachment(ctx, attach)
}

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@ -28,12 +28,13 @@ func IsErrFileTypeForbidden(err error) bool {
}
func (err ErrFileTypeForbidden) Error() string {
return "This file extension or type is not allowed to be uploaded."
return "This file cannot be uploaded or modified due to a forbidden file extension or type."
}
var wildcardTypeRe = regexp.MustCompile(`^[a-z]+/\*$`)
// Verify validates whether a file is allowed to be uploaded.
// Verify validates whether a file is allowed to be uploaded. If buf is empty, it will just check if the file
// has an allowed file extension.
func Verify(buf []byte, fileName, allowedTypesStr string) error {
allowedTypesStr = strings.ReplaceAll(allowedTypesStr, "|", ",") // compat for old config format
@ -56,21 +57,31 @@ func Verify(buf []byte, fileName, allowedTypesStr string) error {
return ErrFileTypeForbidden{Type: fullMimeType}
}
extension := strings.ToLower(path.Ext(fileName))
isBufEmpty := len(buf) <= 1
// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/file#Unique_file_type_specifiers
for _, allowEntry := range allowedTypes {
if allowEntry == "*/*" {
return nil // everything allowed
} else if strings.HasPrefix(allowEntry, ".") && allowEntry == extension {
}
if strings.HasPrefix(allowEntry, ".") && allowEntry == extension {
return nil // extension is allowed
} else if mimeType == allowEntry {
}
if isBufEmpty {
continue // skip mime type checks if buffer is empty
}
if mimeType == allowEntry {
return nil // mime type is allowed
} else if wildcardTypeRe.MatchString(allowEntry) && strings.HasPrefix(mimeType, allowEntry[:len(allowEntry)-1]) {
}
if wildcardTypeRe.MatchString(allowEntry) && strings.HasPrefix(mimeType, allowEntry[:len(allowEntry)-1]) {
return nil // wildcard match, e.g. image/*
}
}
if !isBufEmpty {
log.Info("Attachment with type %s blocked from upload", fullMimeType)
}
return ErrFileTypeForbidden{Type: fullMimeType}
}

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@ -7706,6 +7706,9 @@
"404": {
"$ref": "#/responses/error"
},
"422": {
"$ref": "#/responses/validationError"
},
"423": {
"$ref": "#/responses/repoArchivedError"
}
@ -8328,6 +8331,9 @@
"404": {
"$ref": "#/responses/error"
},
"422": {
"$ref": "#/responses/validationError"
},
"423": {
"$ref": "#/responses/repoArchivedError"
}
@ -13474,6 +13480,9 @@
},
"404": {
"$ref": "#/responses/notFound"
},
"422": {
"$ref": "#/responses/validationError"
}
}
}

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@ -151,7 +151,7 @@ func TestAPICreateCommentAttachmentWithUnallowedFile(t *testing.T) {
func TestAPIEditCommentAttachment(t *testing.T) {
defer tests.PrepareTestEnv(t)()
const newAttachmentName = "newAttachmentName"
const newAttachmentName = "newAttachmentName.txt"
attachment := unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: 6})
comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: attachment.CommentID})
@ -173,6 +173,27 @@ func TestAPIEditCommentAttachment(t *testing.T) {
unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: apiAttachment.ID, CommentID: comment.ID, Name: apiAttachment.Name})
}
func TestAPIEditCommentAttachmentWithUnallowedFile(t *testing.T) {
defer tests.PrepareTestEnv(t)()
attachment := unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: 6})
comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: attachment.CommentID})
issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: comment.IssueID})
repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: issue.RepoID})
repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
session := loginUser(t, repoOwner.Name)
token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteIssue)
filename := "file.bad"
urlStr := fmt.Sprintf("/api/v1/repos/%s/%s/issues/comments/%d/assets/%d",
repoOwner.Name, repo.Name, comment.ID, attachment.ID)
req := NewRequestWithValues(t, "PATCH", urlStr, map[string]string{
"name": filename,
}).AddTokenAuth(token)
session.MakeRequest(t, req, http.StatusUnprocessableEntity)
}
func TestAPIDeleteCommentAttachment(t *testing.T) {
defer tests.PrepareTestEnv(t)()

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@ -126,7 +126,7 @@ func TestAPICreateIssueAttachmentWithUnallowedFile(t *testing.T) {
func TestAPIEditIssueAttachment(t *testing.T) {
defer tests.PrepareTestEnv(t)()
const newAttachmentName = "newAttachmentName"
const newAttachmentName = "hello_world.txt"
attachment := unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: 1})
repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: attachment.RepoID})
@ -147,6 +147,26 @@ func TestAPIEditIssueAttachment(t *testing.T) {
unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: apiAttachment.ID, IssueID: issue.ID, Name: apiAttachment.Name})
}
func TestAPIEditIssueAttachmentWithUnallowedFile(t *testing.T) {
defer tests.PrepareTestEnv(t)()
attachment := unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: 1})
repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: attachment.RepoID})
issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: attachment.IssueID})
repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
session := loginUser(t, repoOwner.Name)
token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteIssue)
filename := "file.bad"
urlStr := fmt.Sprintf("/api/v1/repos/%s/%s/issues/%d/assets/%d", repoOwner.Name, repo.Name, issue.Index, attachment.ID)
req := NewRequestWithValues(t, "PATCH", urlStr, map[string]string{
"name": filename,
}).AddTokenAuth(token)
session.MakeRequest(t, req, http.StatusUnprocessableEntity)
}
func TestAPIDeleteIssueAttachment(t *testing.T) {
defer tests.PrepareTestEnv(t)()

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@ -0,0 +1,40 @@
// Copyright 2024 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package integration
import (
"fmt"
"net/http"
"testing"
auth_model "code.gitea.io/gitea/models/auth"
repo_model "code.gitea.io/gitea/models/repo"
"code.gitea.io/gitea/models/unittest"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/test"
"code.gitea.io/gitea/tests"
)
func TestAPIEditReleaseAttachmentWithUnallowedFile(t *testing.T) {
// Limit the allowed release types (since by default there is no restriction)
defer test.MockVariableValue(&setting.Repository.Release.AllowedTypes, ".exe")()
defer tests.PrepareTestEnv(t)()
attachment := unittest.AssertExistsAndLoadBean(t, &repo_model.Attachment{ID: 9})
release := unittest.AssertExistsAndLoadBean(t, &repo_model.Release{ID: attachment.ReleaseID})
repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: attachment.RepoID})
repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
session := loginUser(t, repoOwner.Name)
token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
filename := "file.bad"
urlStr := fmt.Sprintf("/api/v1/repos/%s/%s/releases/%d/assets/%d", repoOwner.Name, repo.Name, release.ID, attachment.ID)
req := NewRequestWithValues(t, "PATCH", urlStr, map[string]string{
"name": filename,
}).AddTokenAuth(token)
session.MakeRequest(t, req, http.StatusUnprocessableEntity)
}