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pkg/symlink: avoid following out of scope

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Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
This commit is contained in:
unclejack 2014-10-28 23:18:45 +02:00
parent 1942888a9f
commit ffb90589a5
3 changed files with 172 additions and 27 deletions
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151
symlink/fs_test.go
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@ -46,6 +46,7 @@ func TestFollowSymLinkUnderLinkedDir(t *testing.T) {
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
os.Mkdir(filepath.Join(dir, "realdir"), 0700)
os.Symlink("realdir", filepath.Join(dir, "linkdir"))
@ -97,25 +98,151 @@ func TestFollowSymLinkRelativeLink(t *testing.T) {
}
func TestFollowSymLinkRelativeLinkScope(t *testing.T) {
link := "testdata/fs/a/f"
// avoid letting symlink f lead us out of the "testdata" scope
// we don't normalize because symlink f is in scope and there is no
// information leak
{
link := "testdata/fs/a/f"
rewrite, err := FollowSymlinkInScope(link, "testdata")
if err != nil {
t.Fatal(err)
rewrite, err := FollowSymlinkInScope(link, "testdata")
if err != nil {
t.Fatal(err)
}
if expected := abs(t, "testdata/test"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
}
}
if expected := abs(t, "testdata/test"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
// avoid letting symlink f lead us out of the "testdata/fs" scope
// we don't normalize because symlink f is in scope and there is no
// information leak
{
link := "testdata/fs/a/f"
rewrite, err := FollowSymlinkInScope(link, "testdata/fs")
if err != nil {
t.Fatal(err)
}
if expected := abs(t, "testdata/fs/test"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
}
}
link = "testdata/fs/b/h"
// avoid letting symlink g (pointed at by symlink h) take out of scope
// TODO: we should probably normalize to scope here because ../[....]/root
// is out of scope and we leak information
{
link := "testdata/fs/b/h"
rewrite, err = FollowSymlinkInScope(link, "testdata")
if err != nil {
t.Fatal(err)
rewrite, err := FollowSymlinkInScope(link, "testdata")
if err != nil {
t.Fatal(err)
}
if expected := abs(t, "testdata/root"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
}
}
if expected := abs(t, "testdata/root"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
// avoid letting allowing symlink e lead us to ../b
// normalize to the "testdata/fs/a"
{
link := "testdata/fs/a/e"
rewrite, err := FollowSymlinkInScope(link, "testdata/fs/a")
if err != nil {
t.Fatal(err)
}
if expected := abs(t, "testdata/fs/a"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
}
}
// avoid letting symlink -> ../directory/file escape from scope
// normalize to "testdata/fs/j"
{
link := "testdata/fs/j/k"
rewrite, err := FollowSymlinkInScope(link, "testdata/fs/j")
if err != nil {
t.Fatal(err)
}
if expected := abs(t, "testdata/fs/j"); expected != rewrite {
t.Fatalf("Expected %s got %s", expected, rewrite)
}
}
// make sure we don't allow escaping to /
// normalize to dir
{
dir, err := ioutil.TempDir("", "docker-fs-test")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
linkFile := filepath.Join(dir, "foo")
os.Mkdir(filepath.Join(dir, ""), 0700)
os.Symlink("/", linkFile)
rewrite, err := FollowSymlinkInScope(linkFile, dir)
if err != nil {
t.Fatal(err)
}
if rewrite != dir {
t.Fatalf("Expected %s got %s", dir, rewrite)
}
}
// make sure we don't allow escaping to /
// normalize to dir
{
dir, err := ioutil.TempDir("", "docker-fs-test")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
linkFile := filepath.Join(dir, "foo")
os.Mkdir(filepath.Join(dir, ""), 0700)
os.Symlink("/../../", linkFile)
rewrite, err := FollowSymlinkInScope(linkFile, dir)
if err != nil {
t.Fatal(err)
}
if rewrite != dir {
t.Fatalf("Expected %s got %s", dir, rewrite)
}
}
// make sure we stay in scope without leaking information
// this also checks for escaping to /
// normalize to dir
{
dir, err := ioutil.TempDir("", "docker-fs-test")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
linkFile := filepath.Join(dir, "foo")
os.Mkdir(filepath.Join(dir, ""), 0700)
os.Symlink("../../", linkFile)
rewrite, err := FollowSymlinkInScope(linkFile, dir)
if err != nil {
t.Fatal(err)
}
if rewrite != dir {
t.Fatalf("Expected %s got %s", dir, rewrite)
}
}
}