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gecko-dev/netwerk/mime/nsMIMEHeaderParamImpl.cpp

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41 KiB
C++
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et tw=80 : */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <string.h>
#include "prprf.h"
#include "plstr.h"
#include "prmem.h"
#include "plbase64.h"
#include "nsCRT.h"
#include "nsMemory.h"
#include "nsTArray.h"
#include "nsCOMPtr.h"
#include "nsEscape.h"
#include "nsMIMEHeaderParamImpl.h"
#include "nsReadableUtils.h"
#include "nsNativeCharsetUtils.h"
#include "nsError.h"
#include "mozilla/Encoding.h"
#include "mozilla/TextUtils.h"
#include "mozilla/Utf8.h"
using mozilla::Encoding;
using mozilla::IsAscii;
using mozilla::IsUtf8;
// static functions declared below are moved from mailnews/mime/src/comi18n.cpp
static char* DecodeQ(const char*, uint32_t);
static bool Is7bitNonAsciiString(const char*, uint32_t);
static void CopyRawHeader(const char*, uint32_t, const nsACString&,
nsACString&);
static nsresult DecodeRFC2047Str(const char*, const nsACString&, bool,
nsACString&);
static nsresult internalDecodeParameter(const nsACString&, const nsACString&,
const nsACString&, bool, bool,
nsACString&);
static nsresult ToUTF8(const nsACString& aString, const nsACString& aCharset,
bool aAllowSubstitution, nsACString& aResult) {
if (aCharset.IsEmpty()) {
return NS_ERROR_INVALID_ARG;
}
auto encoding = Encoding::ForLabelNoReplacement(aCharset);
if (!encoding) {
return NS_ERROR_UCONV_NOCONV;
}
if (aAllowSubstitution) {
nsresult rv = encoding->DecodeWithoutBOMHandling(aString, aResult);
if (NS_SUCCEEDED(rv)) {
return NS_OK;
}
return rv;
}
return encoding->DecodeWithoutBOMHandlingAndWithoutReplacement(aString,
aResult);
}
static nsresult ConvertStringToUTF8(const nsACString& aString,
const nsACString& aCharset, bool aSkipCheck,
bool aAllowSubstitution,
nsACString& aUTF8String) {
// return if ASCII only or valid UTF-8 providing that the ASCII/UTF-8
// check is requested. It may not be asked for if a caller suspects
// that the input is in non-ASCII 7bit charset (ISO-2022-xx, HZ) or
// it's in a charset other than UTF-8 that can be mistaken for UTF-8.
if (!aSkipCheck && (IsAscii(aString) || IsUtf8(aString))) {
aUTF8String = aString;
return NS_OK;
}
aUTF8String.Truncate();
nsresult rv = ToUTF8(aString, aCharset, aAllowSubstitution, aUTF8String);
// additional protection for cases where check is skipped and the input
// is actually in UTF-8 as opposed to aCharset. (i.e. caller's hunch
// was wrong.) We don't check ASCIIness assuming there's no charset
// incompatible with ASCII (we don't support EBCDIC).
if (aSkipCheck && NS_FAILED(rv) && IsUtf8(aString)) {
aUTF8String = aString;
return NS_OK;
}
return rv;
}
// XXX The chance of UTF-7 being used in the message header is really
// low, but in theory it's possible.
#define IS_7BIT_NON_ASCII_CHARSET(cset) \
(!nsCRT::strncasecmp((cset), "ISO-2022", 8) || \
!nsCRT::strncasecmp((cset), "HZ-GB", 5) || \
!nsCRT::strncasecmp((cset), "UTF-7", 5))
NS_IMPL_ISUPPORTS(nsMIMEHeaderParamImpl, nsIMIMEHeaderParam)
NS_IMETHODIMP
nsMIMEHeaderParamImpl::GetParameter(const nsACString& aHeaderVal,
const char* aParamName,
const nsACString& aFallbackCharset,
bool aTryLocaleCharset, char** aLang,
nsAString& aResult) {
return DoGetParameter(aHeaderVal, aParamName, MIME_FIELD_ENCODING,
aFallbackCharset, aTryLocaleCharset, aLang, aResult);
}
NS_IMETHODIMP
nsMIMEHeaderParamImpl::GetParameterHTTP(const nsACString& aHeaderVal,
const char* aParamName,
const nsACString& aFallbackCharset,
bool aTryLocaleCharset, char** aLang,
nsAString& aResult) {
return DoGetParameter(aHeaderVal, aParamName, HTTP_FIELD_ENCODING,
aFallbackCharset, aTryLocaleCharset, aLang, aResult);
}
/* static */
nsresult nsMIMEHeaderParamImpl::GetParameterHTTP(const nsACString& aHeaderVal,
const char* aParamName,
nsAString& aResult) {
return DoGetParameter(aHeaderVal, aParamName, HTTP_FIELD_ENCODING,
EmptyCString(), false, nullptr, aResult);
}
// XXX : aTryLocaleCharset is not yet effective.
/* static */
nsresult nsMIMEHeaderParamImpl::DoGetParameter(
const nsACString& aHeaderVal, const char* aParamName,
ParamDecoding aDecoding, const nsACString& aFallbackCharset,
bool aTryLocaleCharset, char** aLang, nsAString& aResult) {
aResult.Truncate();
nsresult rv;
// get parameter (decode RFC 2231/5987 when applicable, as specified by
// aDecoding (5987 being a subset of 2231) and return charset.)
nsCString med;
nsCString charset;
rv = DoParameterInternal(PromiseFlatCString(aHeaderVal).get(), aParamName,
aDecoding, getter_Copies(charset), aLang,
getter_Copies(med));
if (NS_FAILED(rv)) return rv;
// convert to UTF-8 after charset conversion and RFC 2047 decoding
// if necessary.
nsAutoCString str1;
rv = internalDecodeParameter(med, charset, EmptyCString(), false,
// was aDecoding == MIME_FIELD_ENCODING
// see bug 875615
true, str1);
NS_ENSURE_SUCCESS(rv, rv);
if (!aFallbackCharset.IsEmpty()) {
const Encoding* encoding = Encoding::ForLabel(aFallbackCharset);
nsAutoCString str2;
if (NS_SUCCEEDED(ConvertStringToUTF8(str1, aFallbackCharset, false,
encoding != UTF_8_ENCODING, str2))) {
CopyUTF8toUTF16(str2, aResult);
return NS_OK;
}
}
if (IsUtf8(str1)) {
CopyUTF8toUTF16(str1, aResult);
return NS_OK;
}
if (aTryLocaleCharset && !NS_IsNativeUTF8())
return NS_CopyNativeToUnicode(str1, aResult);
CopyASCIItoUTF16(str1, aResult);
return NS_OK;
}
// remove backslash-encoded sequences from quoted-strings
// modifies string in place, potentially shortening it
void RemoveQuotedStringEscapes(char* src) {
char* dst = src;
for (char* c = src; *c; ++c) {
if (c[0] == '\\' && c[1]) {
// skip backslash if not at end
++c;
}
*dst++ = *c;
}
*dst = 0;
}
// true is character is a hex digit
bool IsHexDigit(char aChar) {
char c = aChar;
return (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F') ||
(c >= '0' && c <= '9');
}
// validate that a C String containing %-escapes is syntactically valid
bool IsValidPercentEscaped(const char* aValue, int32_t len) {
for (int32_t i = 0; i < len; i++) {
if (aValue[i] == '%') {
if (!IsHexDigit(aValue[i + 1]) || !IsHexDigit(aValue[i + 2])) {
return false;
}
}
}
return true;
}
// Support for continuations (RFC 2231, Section 3)
// only a sane number supported
#define MAX_CONTINUATIONS 999
// part of a continuation
class Continuation {
public:
Continuation(const char* aValue, uint32_t aLength, bool aNeedsPercentDecoding,
bool aWasQuotedString) {
value = aValue;
length = aLength;
needsPercentDecoding = aNeedsPercentDecoding;
wasQuotedString = aWasQuotedString;
}
Continuation() {
// empty constructor needed for nsTArray
value = nullptr;
length = 0;
needsPercentDecoding = false;
wasQuotedString = false;
}
~Continuation() = default;
const char* value;
uint32_t length;
bool needsPercentDecoding;
bool wasQuotedString;
};
// combine segments into a single string, returning the allocated string
// (or nullptr) while emptying the list
char* combineContinuations(nsTArray<Continuation>& aArray) {
// Sanity check
if (aArray.Length() == 0) return nullptr;
// Get an upper bound for the length
uint32_t length = 0;
for (uint32_t i = 0; i < aArray.Length(); i++) {
length += aArray[i].length;
}
// Allocate
char* result = (char*)moz_xmalloc(length + 1);
// Concatenate
*result = '\0';
for (uint32_t i = 0; i < aArray.Length(); i++) {
Continuation cont = aArray[i];
if (!cont.value) break;
char* c = result + strlen(result);
strncat(result, cont.value, cont.length);
if (cont.needsPercentDecoding) {
nsUnescape(c);
}
if (cont.wasQuotedString) {
RemoveQuotedStringEscapes(c);
}
}
// return null if empty value
if (*result == '\0') {
free(result);
result = nullptr;
}
return result;
}
// add a continuation, return false on error if segment already has been seen
bool addContinuation(nsTArray<Continuation>& aArray, uint32_t aIndex,
const char* aValue, uint32_t aLength,
bool aNeedsPercentDecoding, bool aWasQuotedString) {
if (aIndex < aArray.Length() && aArray[aIndex].value) {
NS_WARNING("duplicate RC2231 continuation segment #\n");
return false;
}
if (aIndex > MAX_CONTINUATIONS) {
NS_WARNING("RC2231 continuation segment # exceeds limit\n");
return false;
}
if (aNeedsPercentDecoding && aWasQuotedString) {
NS_WARNING(
"RC2231 continuation segment can't use percent encoding and quoted "
"string form at the same time\n");
return false;
}
Continuation cont(aValue, aLength, aNeedsPercentDecoding, aWasQuotedString);
if (aArray.Length() <= aIndex) {
aArray.SetLength(aIndex + 1);
}
aArray[aIndex] = cont;
return true;
}
// parse a segment number; return -1 on error
int32_t parseSegmentNumber(const char* aValue, int32_t aLen) {
if (aLen < 1) {
NS_WARNING("segment number missing\n");
return -1;
}
if (aLen > 1 && aValue[0] == '0') {
NS_WARNING("leading '0' not allowed in segment number\n");
return -1;
}
int32_t segmentNumber = 0;
for (int32_t i = 0; i < aLen; i++) {
if (!(aValue[i] >= '0' && aValue[i] <= '9')) {
NS_WARNING("invalid characters in segment number\n");
return -1;
}
segmentNumber *= 10;
segmentNumber += aValue[i] - '0';
if (segmentNumber > MAX_CONTINUATIONS) {
NS_WARNING("Segment number exceeds sane size\n");
return -1;
}
}
return segmentNumber;
}
// validate a given octet sequence for compliance with the specified
// encoding
bool IsValidOctetSequenceForCharset(const nsACString& aCharset,
const char* aOctets) {
nsAutoCString tmpRaw;
tmpRaw.Assign(aOctets);
nsAutoCString tmpDecoded;
nsresult rv = ConvertStringToUTF8(tmpRaw, aCharset, false, false, tmpDecoded);
if (rv != NS_OK) {
// we can't decode; charset may be unsupported, or the octet sequence
// is broken (illegal or incomplete octet sequence contained)
NS_WARNING(
"RFC2231/5987 parameter value does not decode according to specified "
"charset\n");
return false;
}
return true;
}
// moved almost verbatim from mimehdrs.cpp
// char *
// MimeHeaders_get_parameter (const char *header_value, const char *parm_name,
// char **charset, char **language)
//
// The format of these header lines is
// <token> [ ';' <token> '=' <token-or-quoted-string> ]*
NS_IMETHODIMP
nsMIMEHeaderParamImpl::GetParameterInternal(const char* aHeaderValue,
const char* aParamName,
char** aCharset, char** aLang,
char** aResult) {
return DoParameterInternal(aHeaderValue, aParamName, MIME_FIELD_ENCODING,
aCharset, aLang, aResult);
}
/* static */
nsresult nsMIMEHeaderParamImpl::DoParameterInternal(
const char* aHeaderValue, const char* aParamName, ParamDecoding aDecoding,
char** aCharset, char** aLang, char** aResult) {
if (!aHeaderValue || !*aHeaderValue || !aResult) return NS_ERROR_INVALID_ARG;
*aResult = nullptr;
if (aCharset) *aCharset = nullptr;
if (aLang) *aLang = nullptr;
nsAutoCString charset;
// change to (aDecoding != HTTP_FIELD_ENCODING) when we want to disable
// them for HTTP header fields later on, see bug 776324
bool acceptContinuations = true;
const char* str = aHeaderValue;
// skip leading white space.
for (; *str && nsCRT::IsAsciiSpace(*str); ++str)
;
const char* start = str;
// aParamName is empty. return the first (possibly) _unnamed_ 'parameter'
// For instance, return 'inline' in the following case:
// Content-Disposition: inline; filename=.....
if (!aParamName || !*aParamName) {
for (; *str && *str != ';' && !nsCRT::IsAsciiSpace(*str); ++str)
;
if (str == start) return NS_ERROR_FIRST_HEADER_FIELD_COMPONENT_EMPTY;
*aResult = (char*)moz_xmemdup(start, (str - start) + 1);
(*aResult)[str - start] = '\0'; // null-terminate
return NS_OK;
}
/* Skip forward to first ';' */
for (; *str && *str != ';' && *str != ','; ++str)
;
if (*str) str++;
/* Skip over following whitespace */
for (; *str && nsCRT::IsAsciiSpace(*str); ++str)
;
// Some broken http servers just specify parameters
// like 'filename' without specifying disposition
// method. Rewind to the first non-white-space
// character.
if (!*str) str = start;
// RFC2231 - The legitimate parm format can be:
// A. title=ThisIsTitle
// B. title*=us-ascii'en-us'This%20is%20wierd.
// C. title*0*=us-ascii'en'This%20is%20wierd.%20We
// title*1*=have%20to%20support%20this.
// title*2="Else..."
// D. title*0="Hey, what you think you are doing?"
// title*1="There is no charset and lang info."
// RFC5987: only A and B
// collect results for the different algorithms (plain filename,
// RFC5987/2231-encoded filename, + continuations) separately and decide
// which to use at the end
char* caseAResult = nullptr;
char* caseBResult = nullptr;
char* caseCDResult = nullptr;
// collect continuation segments
nsTArray<Continuation> segments;
// our copies of the charset parameter, kept separately as they might
// differ for the two formats
nsDependentCSubstring charsetB, charsetCD;
nsDependentCSubstring lang;
int32_t paramLen = strlen(aParamName);
while (*str) {
// find name/value
const char* nameStart = str;
const char* nameEnd = nullptr;
const char* valueStart = nullptr;
const char* valueEnd = nullptr;
bool isQuotedString = false;
NS_ASSERTION(!nsCRT::IsAsciiSpace(*str), "should be after whitespace.");
// Skip forward to the end of this token.
for (; *str && !nsCRT::IsAsciiSpace(*str) && *str != '=' && *str != ';';
str++)
;
nameEnd = str;
int32_t nameLen = nameEnd - nameStart;
// Skip over whitespace, '=', and whitespace
while (nsCRT::IsAsciiSpace(*str)) ++str;
if (!*str) {
break;
}
if (*str != '=') {
// don't accept parameters without "="
goto increment_str;
}
// Skip over '=' only if it was actually there
str++;
while (nsCRT::IsAsciiSpace(*str)) ++str;
if (*str != '"') {
// The value is a token, not a quoted string.
valueStart = str;
for (valueEnd = str;
*valueEnd && !nsCRT::IsAsciiSpace(*valueEnd) && *valueEnd != ';';
valueEnd++)
;
str = valueEnd;
} else {
isQuotedString = true;
++str;
valueStart = str;
for (valueEnd = str; *valueEnd; ++valueEnd) {
if (*valueEnd == '\\' && *(valueEnd + 1))
++valueEnd;
else if (*valueEnd == '"')
break;
}
str = valueEnd;
// *valueEnd != null means that *valueEnd is quote character.
if (*valueEnd) str++;
}
// See if this is the simplest case (case A above),
// a 'single' line value with no charset and lang.
// If so, copy it and return.
if (nameLen == paramLen &&
!nsCRT::strncasecmp(nameStart, aParamName, paramLen)) {
if (caseAResult) {
// we already have one caseA result, ignore subsequent ones
goto increment_str;
}
// if the parameter spans across multiple lines we have to strip out the
// line continuation -- jht 4/29/98
nsAutoCString tempStr(valueStart, valueEnd - valueStart);
tempStr.StripCRLF();
char* res = ToNewCString(tempStr);
NS_ENSURE_TRUE(res, NS_ERROR_OUT_OF_MEMORY);
if (isQuotedString) RemoveQuotedStringEscapes(res);
caseAResult = res;
// keep going, we may find a RFC 2231/5987 encoded alternative
}
// case B, C, and D
else if (nameLen > paramLen &&
!nsCRT::strncasecmp(nameStart, aParamName, paramLen) &&
*(nameStart + paramLen) == '*') {
// 1st char past '*'
const char* cp = nameStart + paramLen + 1;
// if param name ends in "*" we need do to RFC5987 "ext-value" decoding
bool needExtDecoding = *(nameEnd - 1) == '*';
bool caseB = nameLen == paramLen + 1;
bool caseCStart = (*cp == '0') && needExtDecoding;
// parse the segment number
int32_t segmentNumber = -1;
if (!caseB) {
int32_t segLen = (nameEnd - cp) - (needExtDecoding ? 1 : 0);
segmentNumber = parseSegmentNumber(cp, segLen);
if (segmentNumber == -1) {
acceptContinuations = false;
goto increment_str;
}
}
// CaseB and start of CaseC: requires charset and optional language
// in quotes (quotes required even if lang is blank)
if (caseB || (caseCStart && acceptContinuations)) {
// look for single quotation mark(')
const char* sQuote1 = PL_strchr(valueStart, 0x27);
const char* sQuote2 = sQuote1 ? PL_strchr(sQuote1 + 1, 0x27) : nullptr;
// Two single quotation marks must be present even in
// absence of charset and lang.
if (!sQuote1 || !sQuote2) {
NS_WARNING(
"Mandatory two single quotes are missing in header parameter\n");
}
const char* charsetStart = nullptr;
int32_t charsetLength = 0;
const char* langStart = nullptr;
int32_t langLength = 0;
const char* rawValStart = nullptr;
int32_t rawValLength = 0;
if (sQuote2 && sQuote1) {
// both delimiters present: charSet'lang'rawVal
rawValStart = sQuote2 + 1;
rawValLength = valueEnd - rawValStart;
langStart = sQuote1 + 1;
langLength = sQuote2 - langStart;
charsetStart = valueStart;
charsetLength = sQuote1 - charsetStart;
} else if (sQuote1) {
// one delimiter; assume charset'rawVal
rawValStart = sQuote1 + 1;
rawValLength = valueEnd - rawValStart;
charsetStart = valueStart;
charsetLength = sQuote1 - valueStart;
} else {
// no delimiter: just rawVal
rawValStart = valueStart;
rawValLength = valueEnd - valueStart;
}
if (langLength != 0) {
lang.Assign(langStart, langLength);
}
// keep the charset for later
if (caseB) {
charsetB.Assign(charsetStart, charsetLength);
} else {
// if caseCorD
charsetCD.Assign(charsetStart, charsetLength);
}
// non-empty value part
if (rawValLength > 0) {
if (!caseBResult && caseB) {
if (!IsValidPercentEscaped(rawValStart, rawValLength)) {
goto increment_str;
}
// allocate buffer for the raw value
char* tmpResult = (char*)moz_xmemdup(rawValStart, rawValLength + 1);
*(tmpResult + rawValLength) = 0;
nsUnescape(tmpResult);
caseBResult = tmpResult;
} else {
// caseC
bool added = addContinuation(segments, 0, rawValStart, rawValLength,
needExtDecoding, isQuotedString);
if (!added) {
// continuation not added, stop processing them
acceptContinuations = false;
}
}
}
} // end of if-block : title*0*= or title*=
// caseD: a line of multiline param with no need for unescaping :
// title*[0-9]= or 2nd or later lines of a caseC param : title*[1-9]*=
else if (acceptContinuations && segmentNumber != -1) {
uint32_t valueLength = valueEnd - valueStart;
bool added =
addContinuation(segments, segmentNumber, valueStart, valueLength,
needExtDecoding, isQuotedString);
if (!added) {
// continuation not added, stop processing them
acceptContinuations = false;
}
} // end of if-block : title*[0-9]= or title*[1-9]*=
}
// str now points after the end of the value.
// skip over whitespace, ';', whitespace.
increment_str:
while (nsCRT::IsAsciiSpace(*str)) ++str;
if (*str == ';') {
++str;
} else {
// stop processing the header field; either we are done or the
// separator was missing
break;
}
while (nsCRT::IsAsciiSpace(*str)) ++str;
}
caseCDResult = combineContinuations(segments);
if (caseBResult && !charsetB.IsEmpty()) {
// check that the 2231/5987 result decodes properly given the
// specified character set
if (!IsValidOctetSequenceForCharset(charsetB, caseBResult))
caseBResult = nullptr;
}
if (caseCDResult && !charsetCD.IsEmpty()) {
// check that the 2231/5987 result decodes properly given the
// specified character set
if (!IsValidOctetSequenceForCharset(charsetCD, caseCDResult))
caseCDResult = nullptr;
}
if (caseBResult) {
// prefer simple 5987 format over 2231 with continuations
*aResult = caseBResult;
caseBResult = nullptr;
charset.Assign(charsetB);
} else if (caseCDResult) {
// prefer 2231/5987 with or without continuations over plain format
*aResult = caseCDResult;
caseCDResult = nullptr;
charset.Assign(charsetCD);
} else if (caseAResult) {
*aResult = caseAResult;
caseAResult = nullptr;
}
// free unused stuff
free(caseAResult);
free(caseBResult);
free(caseCDResult);
// if we have a result
if (*aResult) {
// then return charset and lang as well
if (aLang && !lang.IsEmpty()) {
uint32_t len = lang.Length();
*aLang = (char*)moz_xmemdup(lang.BeginReading(), len + 1);
*(*aLang + len) = 0;
}
if (aCharset && !charset.IsEmpty()) {
uint32_t len = charset.Length();
*aCharset = (char*)moz_xmemdup(charset.BeginReading(), len + 1);
*(*aCharset + len) = 0;
}
}
return *aResult ? NS_OK : NS_ERROR_INVALID_ARG;
}
nsresult internalDecodeRFC2047Header(const char* aHeaderVal,
const nsACString& aDefaultCharset,
bool aOverrideCharset,
bool aEatContinuations,
nsACString& aResult) {
aResult.Truncate();
if (!aHeaderVal) return NS_ERROR_INVALID_ARG;
if (!*aHeaderVal) return NS_OK;
// If aHeaderVal is RFC 2047 encoded or is not a UTF-8 string but
// aDefaultCharset is specified, decodes RFC 2047 encoding and converts
// to UTF-8. Otherwise, just strips away CRLF.
if (PL_strstr(aHeaderVal, "=?") ||
(!aDefaultCharset.IsEmpty() &&
(!IsUtf8(nsDependentCString(aHeaderVal)) ||
Is7bitNonAsciiString(aHeaderVal, strlen(aHeaderVal))))) {
DecodeRFC2047Str(aHeaderVal, aDefaultCharset, aOverrideCharset, aResult);
} else if (aEatContinuations &&
(PL_strchr(aHeaderVal, '\n') || PL_strchr(aHeaderVal, '\r'))) {
aResult = aHeaderVal;
} else {
aEatContinuations = false;
aResult = aHeaderVal;
}
if (aEatContinuations) {
nsAutoCString temp(aResult);
temp.ReplaceSubstring("\n\t", " ");
temp.ReplaceSubstring("\r\t", " ");
temp.StripCRLF();
aResult = temp;
}
return NS_OK;
}
NS_IMETHODIMP
nsMIMEHeaderParamImpl::DecodeRFC2047Header(const char* aHeaderVal,
const char* aDefaultCharset,
bool aOverrideCharset,
bool aEatContinuations,
nsACString& aResult) {
return internalDecodeRFC2047Header(aHeaderVal, nsCString(aDefaultCharset),
aOverrideCharset, aEatContinuations,
aResult);
}
// true if the character is allowed in a RFC 5987 value
// see RFC 5987, Section 3.2.1, "attr-char"
bool IsRFC5987AttrChar(char aChar) {
char c = aChar;
return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
(c == '!' || c == '#' || c == '$' || c == '&' || c == '+' ||
c == '-' || c == '.' || c == '^' || c == '_' || c == '`' ||
c == '|' || c == '~');
}
// percent-decode a value
// returns false on failure
bool PercentDecode(nsACString& aValue) {
char* c = (char*)moz_xmalloc(aValue.Length() + 1);
strcpy(c, PromiseFlatCString(aValue).get());
nsUnescape(c);
aValue.Assign(c);
free(c);
return true;
}
// Decode a parameter value using the encoding defined in RFC 5987
//
// charset "'" [ language ] "'" value-chars
NS_IMETHODIMP
nsMIMEHeaderParamImpl::DecodeRFC5987Param(const nsACString& aParamVal,
nsACString& aLang,
nsAString& aResult) {
nsAutoCString charset;
nsAutoCString language;
nsAutoCString value;
uint32_t delimiters = 0;
const nsCString& encoded = PromiseFlatCString(aParamVal);
const char* c = encoded.get();
while (*c) {
char tc = *c++;
if (tc == '\'') {
// single quote
delimiters++;
} else if (((unsigned char)tc) >= 128) {
// fail early, not ASCII
NS_WARNING("non-US-ASCII character in RFC5987-encoded param");
return NS_ERROR_INVALID_ARG;
} else {
if (delimiters == 0) {
// valid characters are checked later implicitly
charset.Append(tc);
} else if (delimiters == 1) {
// no value checking for now
language.Append(tc);
} else if (delimiters == 2) {
if (IsRFC5987AttrChar(tc)) {
value.Append(tc);
} else if (tc == '%') {
if (!IsHexDigit(c[0]) || !IsHexDigit(c[1])) {
// we expect two more characters
NS_WARNING("broken %-escape in RFC5987-encoded param");
return NS_ERROR_INVALID_ARG;
}
value.Append(tc);
// we consume two more
value.Append(*c++);
value.Append(*c++);
} else {
// character not allowed here
NS_WARNING("invalid character in RFC5987-encoded param");
return NS_ERROR_INVALID_ARG;
}
}
}
}
if (delimiters != 2) {
NS_WARNING("missing delimiters in RFC5987-encoded param");
return NS_ERROR_INVALID_ARG;
}
// abort early for unsupported encodings
if (!charset.LowerCaseEqualsLiteral("utf-8")) {
NS_WARNING("unsupported charset in RFC5987-encoded param");
return NS_ERROR_INVALID_ARG;
}
// percent-decode
if (!PercentDecode(value)) {
return NS_ERROR_OUT_OF_MEMORY;
}
// return the encoding
aLang.Assign(language);
// finally convert octet sequence to UTF-8 and be done
nsAutoCString utf8;
nsresult rv = ConvertStringToUTF8(value, charset, true, false, utf8);
NS_ENSURE_SUCCESS(rv, rv);
CopyUTF8toUTF16(utf8, aResult);
return NS_OK;
}
nsresult internalDecodeParameter(const nsACString& aParamValue,
const nsACString& aCharset,
const nsACString& aDefaultCharset,
bool aOverrideCharset, bool aDecode2047,
nsACString& aResult) {
aResult.Truncate();
// If aCharset is given, aParamValue was obtained from RFC2231/5987
// encoding and we're pretty sure that it's in aCharset.
if (!aCharset.IsEmpty()) {
return ConvertStringToUTF8(aParamValue, aCharset, true, true, aResult);
}
const nsCString& param = PromiseFlatCString(aParamValue);
nsAutoCString unQuoted;
nsACString::const_iterator s, e;
param.BeginReading(s);
param.EndReading(e);
// strip '\' when used to quote CR, LF, '"' and '\'
for (; s != e; ++s) {
if ((*s == '\\')) {
if (++s == e) {
--s; // '\' is at the end. move back and append '\'.
} else if (*s != nsCRT::CR && *s != nsCRT::LF && *s != '"' &&
*s != '\\') {
--s; // '\' is not foll. by CR,LF,'"','\'. move back and append '\'
}
// else : skip '\' and append the quoted character.
}
unQuoted.Append(*s);
}
aResult = unQuoted;
nsresult rv = NS_OK;
if (aDecode2047) {
nsAutoCString decoded;
// Try RFC 2047 encoding, instead.
rv = internalDecodeRFC2047Header(unQuoted.get(), aDefaultCharset,
aOverrideCharset, true, decoded);
if (NS_SUCCEEDED(rv) && !decoded.IsEmpty()) aResult = decoded;
}
return rv;
}
NS_IMETHODIMP
nsMIMEHeaderParamImpl::DecodeParameter(const nsACString& aParamValue,
const char* aCharset,
const char* aDefaultCharset,
bool aOverrideCharset,
nsACString& aResult) {
return internalDecodeParameter(aParamValue, nsCString(aCharset),
nsCString(aDefaultCharset), aOverrideCharset,
true, aResult);
}
#define ISHEXCHAR(c) \
((0x30 <= uint8_t(c) && uint8_t(c) <= 0x39) || \
(0x41 <= uint8_t(c) && uint8_t(c) <= 0x46) || \
(0x61 <= uint8_t(c) && uint8_t(c) <= 0x66))
// Decode Q encoding (RFC 2047).
// static
char* DecodeQ(const char* in, uint32_t length) {
char *out, *dest = nullptr;
out = dest = (char*)calloc(length + 1, sizeof(char));
if (dest == nullptr) return nullptr;
while (length > 0) {
unsigned c = 0;
switch (*in) {
case '=':
// check if |in| in the form of '=hh' where h is [0-9a-fA-F].
if (length < 3 || !ISHEXCHAR(in[1]) || !ISHEXCHAR(in[2]))
goto badsyntax;
PR_sscanf(in + 1, "%2X", &c);
*out++ = (char)c;
in += 3;
length -= 3;
break;
case '_':
*out++ = ' ';
in++;
length--;
break;
default:
if (*in & 0x80) goto badsyntax;
*out++ = *in++;
length--;
}
}
*out++ = '\0';
for (out = dest; *out; ++out) {
if (*out == '\t') *out = ' ';
}
return dest;
badsyntax:
free(dest);
return nullptr;
}
// check if input is HZ (a 7bit encoding for simplified Chinese : RFC 1842))
// or has ESC which may be an indication that it's in one of many ISO
// 2022 7bit encodings (e.g. ISO-2022-JP(-2)/CN : see RFC 1468, 1922, 1554).
// static
bool Is7bitNonAsciiString(const char* input, uint32_t len) {
int32_t c;
enum {
hz_initial, // No HZ seen yet
hz_escaped, // Inside an HZ ~{ escape sequence
hz_seen, // Have seen at least one complete HZ sequence
hz_notpresent // Have seen something that is not legal HZ
} hz_state;
hz_state = hz_initial;
while (len) {
c = uint8_t(*input++);
len--;
if (c & 0x80) return false;
if (c == 0x1B) return true;
if (c == '~') {
switch (hz_state) {
case hz_initial:
case hz_seen:
if (*input == '{') {
hz_state = hz_escaped;
} else if (*input == '~') {
// ~~ is the HZ encoding of ~. Skip over second ~ as well
hz_state = hz_seen;
input++;
len--;
} else {
hz_state = hz_notpresent;
}
break;
case hz_escaped:
if (*input == '}') hz_state = hz_seen;
break;
default:
break;
}
}
}
return hz_state == hz_seen;
}
#define REPLACEMENT_CHAR "\357\277\275" // EF BF BD (UTF-8 encoding of U+FFFD)
// copy 'raw' sequences of octets in aInput to aOutput.
// If aDefaultCharset is specified, the input is assumed to be in the
// charset and converted to UTF-8. Otherwise, a blind copy is made.
// If aDefaultCharset is specified, but the conversion to UTF-8
// is not successful, each octet is replaced by Unicode replacement
// chars. *aOutput is advanced by the number of output octets.
// static
void CopyRawHeader(const char* aInput, uint32_t aLen,
const nsACString& aDefaultCharset, nsACString& aOutput) {
int32_t c;
// If aDefaultCharset is not specified, make a blind copy.
if (aDefaultCharset.IsEmpty()) {
aOutput.Append(aInput, aLen);
return;
}
// Copy as long as it's US-ASCII. An ESC may indicate ISO 2022
// A ~ may indicate it is HZ
while (aLen && (c = uint8_t(*aInput++)) != 0x1B && c != '~' && !(c & 0x80)) {
aOutput.Append(char(c));
aLen--;
}
if (!aLen) {
return;
}
aInput--;
// skip ASCIIness/UTF8ness test if aInput is supected to be a 7bit non-ascii
// string and aDefaultCharset is a 7bit non-ascii charset.
bool skipCheck =
(c == 0x1B || c == '~') &&
IS_7BIT_NON_ASCII_CHARSET(PromiseFlatCString(aDefaultCharset).get());
// If not UTF-8, treat as default charset
nsAutoCString utf8Text;
if (NS_SUCCEEDED(ConvertStringToUTF8(Substring(aInput, aInput + aLen),
PromiseFlatCString(aDefaultCharset),
skipCheck, true, utf8Text))) {
aOutput.Append(utf8Text);
} else { // replace each octet with Unicode replacement char in UTF-8.
for (uint32_t i = 0; i < aLen; i++) {
c = uint8_t(*aInput++);
if (c & 0x80)
aOutput.Append(REPLACEMENT_CHAR);
else
aOutput.Append(char(c));
}
}
}
nsresult DecodeQOrBase64Str(const char* aEncoded, size_t aLen, char aQOrBase64,
const nsACString& aCharset, nsACString& aResult) {
char* decodedText;
bool b64alloc = false;
NS_ASSERTION(aQOrBase64 == 'Q' || aQOrBase64 == 'B', "Should be 'Q' or 'B'");
if (aQOrBase64 == 'Q')
decodedText = DecodeQ(aEncoded, aLen);
else if (aQOrBase64 == 'B') {
decodedText = PL_Base64Decode(aEncoded, aLen, nullptr);
b64alloc = true;
} else {
return NS_ERROR_INVALID_ARG;
}
if (!decodedText) {
return NS_ERROR_INVALID_ARG;
}
nsAutoCString utf8Text;
// skip ASCIIness/UTF8ness test if aCharset is 7bit non-ascii charset.
nsresult rv = ConvertStringToUTF8(
nsDependentCString(decodedText), aCharset,
IS_7BIT_NON_ASCII_CHARSET(PromiseFlatCString(aCharset).get()), true,
utf8Text);
if (b64alloc) {
PR_Free(decodedText);
} else {
free(decodedText);
}
if (NS_FAILED(rv)) {
return rv;
}
aResult.Append(utf8Text);
return NS_OK;
}
static const char especials[] = R"(()<>@,;:\"/[]?.=)";
// |decode_mime_part2_str| taken from comi18n.c
// Decode RFC2047-encoded words in the input and convert the result to UTF-8.
// If aOverrideCharset is true, charset in RFC2047-encoded words is
// ignored and aDefaultCharset is assumed, instead. aDefaultCharset
// is also used to convert raw octets (without RFC 2047 encoding) to UTF-8.
// static
nsresult DecodeRFC2047Str(const char* aHeader,
const nsACString& aDefaultCharset,
bool aOverrideCharset, nsACString& aResult) {
const char *p, *q = nullptr, *r;
const char* begin; // tracking pointer for where we are in the input buffer
int32_t isLastEncodedWord = 0;
const char *charsetStart, *charsetEnd;
nsAutoCString prevCharset, curCharset;
nsAutoCString encodedText;
char prevEncoding = '\0', curEncoding;
nsresult rv;
begin = aHeader;
// To avoid buffer realloc, if possible, set capacity in advance. No
// matter what, more than 3x expansion can never happen for all charsets
// supported by Mozilla. SCSU/BCSU with the sliding window set to a
// non-BMP block may be exceptions, but Mozilla does not support them.
// Neither any known mail/news program use them. Even if there's, we're
// safe because we don't use a raw *char any more.
aResult.SetCapacity(3 * strlen(aHeader));
while ((p = PL_strstr(begin, "=?")) != nullptr) {
if (isLastEncodedWord) {
// See if it's all whitespace.
for (q = begin; q < p; ++q) {
if (!PL_strchr(" \t\r\n", *q)) break;
}
}
if (!isLastEncodedWord || q < p) {
if (!encodedText.IsEmpty()) {
rv = DecodeQOrBase64Str(encodedText.get(), encodedText.Length(),
prevEncoding, prevCharset, aResult);
if (NS_FAILED(rv)) {
aResult.Append(encodedText);
}
encodedText.Truncate();
prevCharset.Truncate();
prevEncoding = '\0';
}
// copy the part before the encoded-word
CopyRawHeader(begin, p - begin, aDefaultCharset, aResult);
begin = p;
}
p += 2;
// Get charset info
charsetStart = p;
charsetEnd = nullptr;
for (q = p; *q != '?'; q++) {
if (*q <= ' ' || PL_strchr(especials, *q)) {
goto badsyntax;
}
// RFC 2231 section 5
if (!charsetEnd && *q == '*') {
charsetEnd = q;
}
}
if (!charsetEnd) {
charsetEnd = q;
}
q++;
curEncoding = nsCRT::ToUpper(*q);
if (curEncoding != 'Q' && curEncoding != 'B') goto badsyntax;
if (q[1] != '?') goto badsyntax;
// loop-wise, keep going until we hit "?=". the inner check handles the
// nul terminator should the string terminate before we hit the right
// marker. (And the r[1] will never reach beyond the end of the string
// because *r != '?' is true if r is the nul character.)
for (r = q + 2; *r != '?' || r[1] != '='; r++) {
if (*r < ' ') goto badsyntax;
}
if (r == q + 2) {
// it's empty, skip
begin = r + 2;
isLastEncodedWord = 1;
continue;
}
curCharset.Assign(charsetStart, charsetEnd - charsetStart);
// Override charset if requested. Never override labeled UTF-8.
// Use default charset instead of UNKNOWN-8BIT
if ((aOverrideCharset &&
0 != nsCRT::strcasecmp(curCharset.get(), "UTF-8")) ||
(!aDefaultCharset.IsEmpty() &&
0 == nsCRT::strcasecmp(curCharset.get(), "UNKNOWN-8BIT"))) {
curCharset = aDefaultCharset;
}
const char* R;
R = r;
if (curEncoding == 'B') {
// bug 227290. ignore an extraneous '=' at the end.
// (# of characters in B-encoded part has to be a multiple of 4)
int32_t n = r - (q + 2);
R -= (n % 4 == 1 && !PL_strncmp(r - 3, "===", 3)) ? 1 : 0;
}
// Bug 493544. Don't decode the encoded text until it ends
if (R[-1] != '=' &&
(prevCharset.IsEmpty() ||
(curCharset == prevCharset && curEncoding == prevEncoding))) {
encodedText.Append(q + 2, R - (q + 2));
prevCharset = curCharset;
prevEncoding = curEncoding;
begin = r + 2;
isLastEncodedWord = 1;
continue;
}
bool bDecoded; // If the current line has been decoded.
bDecoded = false;
if (!encodedText.IsEmpty()) {
if (curCharset == prevCharset && curEncoding == prevEncoding) {
encodedText.Append(q + 2, R - (q + 2));
bDecoded = true;
}
rv = DecodeQOrBase64Str(encodedText.get(), encodedText.Length(),
prevEncoding, prevCharset, aResult);
if (NS_FAILED(rv)) {
aResult.Append(encodedText);
}
encodedText.Truncate();
prevCharset.Truncate();
prevEncoding = '\0';
}
if (!bDecoded) {
rv = DecodeQOrBase64Str(q + 2, R - (q + 2), curEncoding, curCharset,
aResult);
if (NS_FAILED(rv)) {
aResult.Append(encodedText);
}
}
begin = r + 2;
isLastEncodedWord = 1;
continue;
badsyntax:
if (!encodedText.IsEmpty()) {
rv = DecodeQOrBase64Str(encodedText.get(), encodedText.Length(),
prevEncoding, prevCharset, aResult);
if (NS_FAILED(rv)) {
aResult.Append(encodedText);
}
encodedText.Truncate();
prevCharset.Truncate();
}
// copy the part before the encoded-word
aResult.Append(begin, p - begin);
begin = p;
isLastEncodedWord = 0;
}
if (!encodedText.IsEmpty()) {
rv = DecodeQOrBase64Str(encodedText.get(), encodedText.Length(),
prevEncoding, prevCharset, aResult);
if (NS_FAILED(rv)) {
aResult.Append(encodedText);
}
}
// put the tail back
CopyRawHeader(begin, strlen(begin), aDefaultCharset, aResult);
nsAutoCString tempStr(aResult);
tempStr.ReplaceChar('\t', ' ');
aResult = tempStr;
return NS_OK;
}
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