diff options
| author | Jakob Unterwurzacher | 2023-07-21 19:31:38 +0200 |
|---|---|---|
| committer | Jakob Unterwurzacher | 2023-09-15 22:29:07 +0200 |
| commit | 7fff33a1e2560c8f4eb1f477c1e220eeb14291ab (patch) | |
| tree | cd875957706c1f81a9eebc91d02bd5dae41163ae | |
| parent | 30c0fbd98ab3606956ea4cf9b99825b942ebe94c (diff) | |
nametransform: reject non-canonical base64
The test added in the earlier commit passes with this
change.
| -rw-r--r-- | internal/nametransform/names.go | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/internal/nametransform/names.go b/internal/nametransform/names.go index 7a983a0..3313a7c 100644 --- a/internal/nametransform/names.go +++ b/internal/nametransform/names.go @@ -4,8 +4,10 @@ package nametransform import ( "crypto/aes" "encoding/base64" + "errors" "math" "path/filepath" + "strings" "syscall" "github.com/rfjakob/eme" @@ -44,6 +46,7 @@ func New(e *eme.EMECipher, longNames bool, longNameMax uint8, raw64 bool, badnam if raw64 { b64 = base64.RawURLEncoding } + b64 = b64.Strict() // Reject non-zero padding bits var effectiveLongNameMax int = math.MaxInt32 if longNames { if longNameMax == 0 { @@ -81,6 +84,13 @@ func (n *NameTransform) DecryptName(cipherName string, iv []byte) (string, error // decryptName decrypts a base64-encoded encrypted filename "cipherName" using the // initialization vector "iv". func (n *NameTransform) decryptName(cipherName string, iv []byte) (string, error) { + // From https://pkg.go.dev/encoding/base64#Encoding.Strict : + // > Note that the input is still malleable, as new line characters + // > (CR and LF) are still ignored. + // Check for CR and LF ourselves. + if strings.ContainsAny(cipherName, "\r\n") { + return "", errors.New("characters CR or LF in base64") + } bin, err := n.B64.DecodeString(cipherName) if err != nil { return "", err |