lib: update Pkcs7PaddingUndo, AESDecryptCBC

Add error as the second return value to Pkcs7PaddingUndo and
AESDecryptCBC.

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/blocks.go b/lib/blocks.go
index 9b184d1..c4d8be1 100644
--- a/lib/blocks.go
+++ b/lib/blocks.go
@@ -112,15 +112,15 @@ func Pkcs7Padding(in []byte, k int) []byte {
 }
 
 // Removes PKCS#7 Padding from input `in`
-func Pkcs7PaddingUndo(in []byte) []byte {
+func Pkcs7PaddingUndo(in []byte) ([]byte, error) {
 	pd := in[len(in)-1] // padding character
 	pl := int(pd)       // padding length
 
 	// Validate
 	for i := len(in) - 1; i >= len(in)-pl; i-- {
 		if in[i] != pd {
-			panic("input is not pkcs#7 padded!")
+			return []byte{}, CPError{"input is not pkcs#7 padded"}
 		}
 	}
-	return in[0:(len(in) - pl)]
+	return in[0:(len(in) - pl)], nil
 }