encoding/base64: fix decode reports incorrect index
Fix Decode to return the correct illegal data index from a corrupted
input that contains whitespaces.
Fixes #19406
Change-Id: Ib2b2b6ed7e41f024d0da2bd035caec4317c2869c
Reviewed-on: https://go-review.googlesource.com/37837
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/encoding/base64/base64.go b/src/encoding/base64/base64.go
index d2efad4..b15754e 100644
--- a/src/encoding/base64/base64.go
+++ b/src/encoding/base64/base64.go
@@ -254,6 +254,7 @@
// indicates if end-of-message padding or a partial quantum was encountered
// and thus any additional data is an error.
func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
+ var inIdx int
si := 0
// skip over newlines
@@ -275,6 +276,7 @@
break
}
in := src[si]
+ inIdx = si
si++
// skip over newlines
@@ -287,7 +289,7 @@
switch j {
case 0, 1:
// incorrect padding
- return n, false, CorruptInputError(si - 1)
+ return n, false, CorruptInputError(inIdx)
case 2:
// "==" is expected, the first "=" is already consumed.
if si == len(src) {
@@ -314,7 +316,7 @@
}
dbuf[j] = enc.decodeMap[in]
if dbuf[j] == 0xFF {
- return n, false, CorruptInputError(si - 1)
+ return n, false, CorruptInputError(inIdx)
}
}
diff --git a/src/encoding/base64/base64_test.go b/src/encoding/base64/base64_test.go
index e2e1d59..00b3d61 100644
--- a/src/encoding/base64/base64_test.go
+++ b/src/encoding/base64/base64_test.go
@@ -220,6 +220,8 @@
{"AAAA", -1},
{"AAAAAA=", 7},
{"YWJjZA=====", 8},
+ {"A!\n", 1},
+ {"A=\n", 1},
}
for _, tc := range testCases {
dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
