Merge pull request #57 from fako1024/56-optimize-interface-path-trave…

…rsal-sanitization [feature] Optimize path traversal sanitization for link / interface access
fako1024 · Aug 22, 2023 · a7226e9 · a7226e9
2 parents 6e647c8 + 38ee84d
commit a7226e9
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Showing 2 changed files with 11 additions and 11 deletions.
diff --git a/link/interface.go b/link/interface.go
@@ -1,5 +1,7 @@
 package link
 
+import "path/filepath"
+
 // Interface is the low-level representation of a network interface
 type Interface struct {
 	Name  string
@@ -10,13 +12,13 @@ type Interface struct {
 // NewInterface instantiates a new network interface and obtains its basic parameters
 func NewInterface(name string) (iface Interface, err error) {
 	iface = Interface{
-		Name: name,
+		Name: filepath.Clean(name),
 	}
 
-	if iface.Index, err = getIndex(name); err != nil {
+	if iface.Index, err = iface.getIndex(); err != nil {
 		return
 	}
-	if iface.Type, err = getLinkType(name); err != nil {
+	if iface.Type, err = iface.getLinkType(); err != nil {
 		return
 	}
 

diff --git a/link/interface_linux.go b/link/interface_linux.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"math"
 	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"syscall"
@@ -50,7 +49,7 @@ func Interfaces() ([]Interface, error) {
 // IsUp determines if an interface is currently up (at the time of the call)
 func (i Interface) IsUp() (bool, error) {
 
-	data, err := os.ReadFile(filepath.Clean(netBasePath + i.Name + netFlagsPath))
+	data, err := os.ReadFile(netBasePath + i.Name + netFlagsPath)
 	if err != nil {
 		return false, err
 	}
@@ -66,9 +65,9 @@ func (i Interface) IsUp() (bool, error) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-func getIndex(name string) (int, error) {
+func (i Interface) getIndex() (int, error) {
 
-	data, err := os.ReadFile(filepath.Clean(netBasePath + name + netIndexPath))
+	data, err := os.ReadFile(netBasePath + i.Name + netIndexPath)
 	if err != nil {
 		return -1, err
 	}
@@ -87,10 +86,9 @@ func getIndex(name string) (int, error) {
 	return -1, ErrIndexOutOfBounds
 }
 
-func getLinkType(name string) (Type, error) {
+func (i Interface) getLinkType() (Type, error) {
 
-	sysPath := netBasePath + name + netTypePath
-	data, err := os.ReadFile(filepath.Clean(sysPath))
+	data, err := os.ReadFile(netBasePath + i.Name + netTypePath)
 	if err != nil {
 		return -1, err
 	}
@@ -102,7 +100,7 @@ func getLinkType(name string) (Type, error) {
 	}
 
 	if val < 0 || val > 65535 {
-		return -1, fmt.Errorf("invalid link type read from `%s`: %d", sysPath, val)
+		return -1, fmt.Errorf("invalid link type read from `%s`: %d", netBasePath+i.Name+netTypePath, val)
 	}
 
 	return Type(val), nil