The Tor Browser: netwerk/mime/nsMIMEHeaderParamImpl.cpp@b8a032363ba2 (annotated)

netwerk/mime/nsMIMEHeaderParamImpl.cpp@b8a032363ba2 (annotated)

netwerk/mime/nsMIMEHeaderParamImpl.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set sw=4 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 "prmem.h"
 #include "prprf.h"
 #include "plstr.h"
 #include "plbase64.h"
 #include "nsCRT.h"
 #include "nsMemory.h"
 #include "nsTArray.h"
 #include "nsCOMPtr.h"
 #include "nsEscape.h"
 #include "nsIUTF8ConverterService.h"
 #include "nsUConvCID.h"
 #include "nsIServiceManager.h"
 #include "nsMIMEHeaderParamImpl.h"
 #include "nsReadableUtils.h"
 #include "nsNativeCharsetUtils.h"
 #include "nsError.h"
 #include "nsIUnicodeDecoder.h"
 #include "mozilla/dom/EncodingUtils.h"
 using mozilla::dom::EncodingUtils;
 // 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 char *, nsACString &);
 static nsresult DecodeRFC2047Str(const char *, const char *, bool, nsACString&);
 static nsresult internalDecodeParameter(const nsACString&, const char*,
                                         const char*, bool, bool, nsACString&);
 // 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);
 }
 // XXX : aTryLocaleCharset is not yet effective.
 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.)
     nsXPIDLCString med;
     nsXPIDLCString 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.get(), nullptr, false,
                                  // was aDecoding == MIME_FIELD_ENCODING
                                  // see bug 875615
                                  true,
                                  str1);
     NS_ENSURE_SUCCESS(rv, rv);
     if (!aFallbackCharset.IsEmpty())
     {
         nsAutoCString charset;
         EncodingUtils::FindEncodingForLabel(aFallbackCharset, charset);
         nsAutoCString str2;
         nsCOMPtr<nsIUTF8ConverterService>
           cvtUTF8(do_GetService(NS_UTF8CONVERTERSERVICE_CONTRACTID));
         if (cvtUTF8 &&
             NS_SUCCEEDED(cvtUTF8->ConvertStringToUTF8(str1,
                 PromiseFlatCString(aFallbackCharset).get(), false,
                                    !charset.EqualsLiteral("UTF-8"),
 , 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 = 0L;
       length = 0;
       needsPercentDecoding = false;
       wasQuotedString = false;
     }
     ~Continuation() {}
     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 *) nsMemory::Alloc(length + 1);
   // Concatenate
   if (result) {
     *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') {
       nsMemory::Free(result);
       result = nullptr;
     }
   } else {
     // Handle OOM
     NS_WARNING("Out of memory\n");
   }
   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(nsACString& aCharset, const char *aOctets)
 {
   nsCOMPtr<nsIUTF8ConverterService> cvtUTF8(do_GetService
     (NS_UTF8CONVERTERSERVICE_CONTRACTID));
   if (!cvtUTF8) {
     NS_WARNING("Can't get UTF8ConverterService\n");
     return false;
   }
   nsAutoCString tmpRaw;
   tmpRaw.Assign(aOctets);
   nsAutoCString tmpDecoded;
   nsresult rv = cvtUTF8->ConvertStringToUTF8(tmpRaw,
                                              PromiseFlatCString(aCharset).get(),
                                              false, false, 1, 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);
 }
 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 *) nsMemory::Clone(start, (str - start) + 1);
       NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
       (*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 = str;
     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;
     }
     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.StripChars("\r\n");
       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 *) nsMemory::Clone(rawValStart, rawValLength + 1);
             if (!tmpResult) {
               goto increment_str;
             }
             *(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
   nsMemory::Free(caseAResult);
   nsMemory::Free(caseBResult);
   nsMemory::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 *) nsMemory::Clone(lang.BeginReading(), len + 1);
       if (*aLang) {
         *(*aLang + len) = 0;
       }
    }
     if (aCharset && !charset.IsEmpty()) {
       uint32_t len = charset.Length();
       *aCharset = (char *) nsMemory::Clone(charset.BeginReading(), len + 1);
       if (*aCharset) {
         *(*aCharset + len) = 0;
       }
     }
   }
   return *aResult ? NS_OK : NS_ERROR_INVALID_ARG;
 }
 nsresult
 internalDecodeRFC2047Header(const char* aHeaderVal, const char* 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 && (!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.StripChars("\r\n");
     aResult = temp;
   }
   return NS_OK;
 }
 NS_IMETHODIMP
 nsMIMEHeaderParamImpl::DecodeRFC2047Header(const char* aHeaderVal,
                                            const char* aDefaultCharset,
                                            bool aOverrideCharset,
                                            bool aEatContinuations,
                                            nsACString& aResult)
 {
   return internalDecodeRFC2047Header(aHeaderVal, 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 *) nsMemory::Alloc(aValue.Length() + 1);
   if (!c) {
     return false;
   }
   strcpy(c, PromiseFlatCString(aValue).get());
   nsUnescape(c);
   aValue.Assign(c);
   nsMemory::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 char *encoded = PromiseFlatCString(aParamVal).get();
   const char *c = encoded;
   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
   nsresult rv = NS_OK;
   nsCOMPtr<nsIUTF8ConverterService> cvtUTF8 =
     do_GetService(NS_UTF8CONVERTERSERVICE_CONTRACTID, &rv);
   NS_ENSURE_SUCCESS(rv, rv);
   nsAutoCString utf8;
   rv = cvtUTF8->ConvertStringToUTF8(value, charset.get(), true, false, 1, utf8);
   NS_ENSURE_SUCCESS(rv, rv);
   CopyUTF8toUTF16(utf8, aResult);
   return NS_OK;
 }
 nsresult
 internalDecodeParameter(const nsACString& aParamValue, const char* aCharset,
                         const char* 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 && *aCharset)
   {
     nsCOMPtr<nsIUTF8ConverterService> cvtUTF8(do_GetService(NS_UTF8CONVERTERSERVICE_CONTRACTID));
     if (cvtUTF8)
       return cvtUTF8->ConvertStringToUTF8(aParamValue, aCharset,
           true, true, 1, aResult);
   }
   const nsAFlatCString& 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, aCharset, 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 = 0;
   out = dest = (char *)PR_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:
   PR_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 char *aDefaultCharset, nsACString &aOutput)
 {
   int32_t c;
   // If aDefaultCharset is not specified, make a blind copy.
   if (!aDefaultCharset || !*aDefaultCharset) {
     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(aDefaultCharset);
   // If not UTF-8, treat as default charset
   nsCOMPtr<nsIUTF8ConverterService>
     cvtUTF8(do_GetService(NS_UTF8CONVERTERSERVICE_CONTRACTID));
   nsAutoCString utf8Text;
   if (cvtUTF8 &&
       NS_SUCCEEDED(
       cvtUTF8->ConvertStringToUTF8(Substring(aInput, aInput + aLen),
                                    aDefaultCharset, skipCheck, true, 1,
                                    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 char *aCharset, nsACString &aResult)
 {
   char *decodedText;
   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);
   } else {
     return NS_ERROR_INVALID_ARG;
   }
   if (!decodedText) {
     return NS_ERROR_INVALID_ARG;
   }
   nsresult rv;
   nsCOMPtr<nsIUTF8ConverterService>
     cvtUTF8(do_GetService(NS_UTF8CONVERTERSERVICE_CONTRACTID, &rv));
   nsAutoCString utf8Text;
   if (NS_SUCCEEDED(rv)) {
     // skip ASCIIness/UTF8ness test if aCharset is 7bit non-ascii charset.
     rv = cvtUTF8->ConvertStringToUTF8(nsDependentCString(decodedText),
                                       aCharset,
                                       IS_7BIT_NON_ASCII_CHARSET(aCharset),
                                       true, 1, utf8Text);
   }
   PR_Free(decodedText);
   if (NS_FAILED(rv)) {
     return rv;
   }
   aResult.Append(utf8Text);
   return NS_OK;
 }
 static const char especials[] = "()<>@,;:\\\"/[]?.=";
 // |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 char *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, "=?")) != 0) {
     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.get(), 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 = 0;
     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;
     r = q;
     for (r = q + 2; *r != '?'; r++) {
       if (*r < ' ') goto badsyntax;
     }
     if (r[1] != '=')
         goto badsyntax;
     else 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 && 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.get(), 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.get(), 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.get(), 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.get(), 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;
 }

The Tor Browser / annotate

netwerk/mime/nsMIMEHeaderParamImpl.cpp@b8a032363ba2 (annotated)

netwerk/mime/nsMIMEHeaderParamImpl.cpp