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Defend against infinite loop when following symlinks

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ideally it should never reach it, but there was already multiple issues with infinite loop
at following symlinks. this fixes hanging unit tests

Docker-DCO-1.1-Signed-off-by: Lajos Papp <lajos.papp@sequenceiq.com> (github: lalyos)
This commit is contained in:
lalyos 2014-05-16 00:25:38 +02:00
parent 8b77a5b7ae
commit b51c366bfc
1 changed files with 10 additions and 0 deletions
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10
pkg/symlink/fs.go
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@ -3,10 +3,13 @@ package symlink
import ( import (
"fmt" "fmt"
"os" "os"
"path"
"path/filepath" "path/filepath"
"strings" "strings"
) )
const maxLoopCounter = 100
// FollowSymlink will follow an existing link and scope it to the root // FollowSymlink will follow an existing link and scope it to the root
// path provided. // path provided.
func FollowSymlinkInScope(link, root string) (string, error) { func FollowSymlinkInScope(link, root string) (string, error) {
@ -30,7 +33,14 @@ func FollowSymlinkInScope(link, root string) (string, error) {
prev = filepath.Join(prev, p) prev = filepath.Join(prev, p)
prev = filepath.Clean(prev) prev = filepath.Clean(prev)
loopCounter := 0
for { for {
loopCounter++
if loopCounter >= maxLoopCounter {
return "", fmt.Errorf("loopCounter reached MAX: %v", loopCounter)
}
if !strings.HasPrefix(prev, root) { if !strings.HasPrefix(prev, root) {
// Don't resolve symlinks outside of root. For example, // Don't resolve symlinks outside of root. For example,
// we don't have to check /home in the below. // we don't have to check /home in the below.