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|
From: James Hillyerd <james@hillyerd.com>
Date: Thu, 2 Feb 2023 11:50:20 -0800
Subject: fix: Reject invalid MIME header name characters to support Go 1.20
(#270)
* Test with go 1.20 release candidate
* header: Detect invalid header name characters for Go 1.20
* header: test for permitted special chars
Origin: backport, https://github.com/jhillyerd/enmime/commit/415ff72f
---
header.go | 59 +++++++++++++++++++++++++++++++++++++++++++++++++---------
header_test.go | 18 +++++++++++++-----
2 files changed, 63 insertions(+), 14 deletions(-)
diff --git a/header.go b/header.go
index cd9d28b..628e765 100644
--- a/header.go
+++ b/header.go
@@ -81,9 +81,9 @@ var AddressHeaders = map[string]bool{
// ParseMediaType is a more tolerant implementation of Go's mime.ParseMediaType function.
//
// Tolerances accounted for:
-// * Missing ';' between content-type and media parameters
-// * Repeating media parameters
-// * Unquoted values in media parameters containing 'tspecials' characters
+// - Missing ';' between content-type and media parameters
+// - Repeating media parameters
+// - Unquoted values in media parameters containing 'tspecials' characters
func ParseMediaType(ctype string) (mtype string, params map[string]string, invalidParams []string,
err error) {
// Export of internal function.
@@ -97,6 +97,7 @@ func readHeader(r *bufio.Reader, p *Part) (textproto.MIMEHeader, error) {
buf := &bytes.Buffer{}
tp := textproto.NewReader(r)
firstHeader := true
+line:
for {
// Pull out each line of the headers as a temporary slice s
s, err := tp.ReadLineBytes()
@@ -119,18 +120,29 @@ func readHeader(r *bufio.Reader, p *Part) (textproto.MIMEHeader, error) {
continue
}
if firstColon > 0 {
- // Contains a colon, treat as a new header line
- if !firstHeader {
- // New Header line, end the previous
- buf.Write([]byte{'\r', '\n'})
- }
-
// Behavior change in net/textproto package in Golang 1.12.10 and 1.13.1:
// A space preceding the first colon in a header line is no longer handled
// automatically due to CVE-2019-16276 which takes advantage of this
// particular violation of RFC-7230 to exploit HTTP/1.1
if bytes.Contains(s[:firstColon+1], []byte{' ', ':'}) {
s = bytes.Replace(s, []byte{' ', ':'}, []byte{':'}, 1)
+ firstColon = bytes.IndexByte(s, ':')
+ }
+
+ // Behavior change in net/textproto package in Golang 1.20: invalid characters
+ // in header keys are no longer allowed; https://github.com/golang/go/issues/53188
+ for _, c := range s[:firstColon] {
+ if c != ' ' && !validHeaderFieldByte(c) {
+ p.addError(
+ ErrorMalformedHeader, "Header name %q contains invalid character %q", s, c)
+ continue line
+ }
+ }
+
+ // Contains a colon, treat as a new header line
+ if !firstHeader {
+ // New Header line, end the previous
+ buf.Write([]byte{'\r', '\n'})
}
s = textproto.TrimBytes(s)
@@ -213,3 +225,32 @@ func quotedDisplayName(s string) string {
func whiteSpaceRune(r rune) bool {
return r == ' ' || r == '\t' || r == '\r' || r == '\n'
}
+
+// Mirror of func in net/textproto/reader.go; from go 1.20.0-rc.2
+func validHeaderFieldByte(c byte) bool {
+ // mask is a 128-bit bitmap with 1s for allowed bytes,
+ // so that the byte c can be tested with a shift and an and.
+ // If c >= 128, then 1<<c and 1<<(c-64) will both be zero,
+ // and this function will return false.
+ const mask = 0 |
+ (1<<(10)-1)<<'0' |
+ (1<<(26)-1)<<'a' |
+ (1<<(26)-1)<<'A' |
+ 1<<'!' |
+ 1<<'#' |
+ 1<<'$' |
+ 1<<'%' |
+ 1<<'&' |
+ 1<<'\'' |
+ 1<<'*' |
+ 1<<'+' |
+ 1<<'-' |
+ 1<<'.' |
+ 1<<'^' |
+ 1<<'_' |
+ 1<<'`' |
+ 1<<'|' |
+ 1<<'~'
+ return ((uint64(1)<<c)&(mask&(1<<64-1)) |
+ (uint64(1)<<(c-64))&(mask>>64)) != 0
+}
diff --git a/header_test.go b/header_test.go
index 01055be..5b18568 100644
--- a/header_test.go
+++ b/header_test.go
@@ -99,8 +99,6 @@ func TestReadHeader(t *testing.T) {
{
label: "missing name",
input: ": line1=foo\r\n",
- hname: "",
- want: "",
correct: false,
},
{
@@ -127,12 +125,17 @@ func TestReadHeader(t *testing.T) {
correct: true,
},
{
- label: "equals in name",
- input: "name=value:text\n",
- hname: "name=value",
+ label: "permitted specials in name",
+ input: "Begin!#$%&'*+-.^_`|~End: text\n",
+ hname: "Begin!#$%&'*+-.^_`|~End",
want: "text",
correct: true,
},
+ {
+ label: "equals in name",
+ input: "name=value:text\n",
+ correct: false,
+ },
{
label: "no space before continuation",
input: "X-Bad-Continuation: line1=foo;\nline2=bar\n",
@@ -236,6 +239,11 @@ func TestReadHeader(t *testing.T) {
gotErrs := len(p.Errors)
if gotErrs != wantErrs {
t.Errorf("Got %v p.Errors, want %v", gotErrs, wantErrs)
+ if gotErrs > 0 {
+ for _, e := range p.Errors {
+ t.Log(e)
+ }
+ }
}
// Check for extra headers by removing expected ones.
|
