Tokenizer.cc

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#include "squid.h"
#include "debug/Stream.h"
#include "http/one/Parser.h"
#include "http/one/Tokenizer.h"
#include "parser/Tokenizer.h"
#include "sbuf/Stream.h"
 
static SBuf
parseQuotedStringSuffix(Parser::Tokenizer &tok, const bool http1p0)
{
    /*
     * RFC 1945 - defines qdtext:
     *   inclusive of LWS (which includes CR and LF)
     *   exclusive of 0x80-0xFF
     *   includes 0x5C ('\') as just a regular character
     */
    static const CharacterSet qdtext1p0 = CharacterSet("qdtext (HTTP/1.0)", 0x23, 0x7E) +
                                          CharacterSet("", "!") +
                                          CharacterSet::CR + CharacterSet::LF + CharacterSet::HTAB + CharacterSet::SP;
    /*
     * RFC 7230 - defines qdtext:
     *   exclusive of CR and LF
     *   inclusive of 0x80-0xFF
     *   includes 0x5C ('\') but only when part of quoted-pair
     */
    static const CharacterSet qdtext1p1 = CharacterSet("qdtext (HTTP/1.1)", 0x23, 0x5B) +
                                          CharacterSet("", "!") +
                                          CharacterSet("", 0x5D, 0x7E) +
                                          CharacterSet::HTAB + CharacterSet::SP +
                                          CharacterSet::OBSTEXT;
 
    // best we can do is a conditional reference since http1p0 value may change per-client
    const CharacterSet &tokenChars = (http1p0 ? qdtext1p0 : qdtext1p1);
 
    SBuf parsedToken;
 
    while (!tok.atEnd()) {
        SBuf qdText;
        if (tok.prefix(qdText, tokenChars))
            parsedToken.append(qdText);
 
        if (!http1p0 && tok.skip('\\')) { // HTTP/1.1 allows quoted-pair, HTTP/1.0 does not
            if (tok.atEnd())
                break;
 
            /* RFC 7230 section 3.2.6
             *
             * The backslash octet ("\") can be used as a single-octet quoting
             * mechanism within quoted-string and comment constructs.  Recipients
             * that process the value of a quoted-string MUST handle a quoted-pair
             * as if it were replaced by the octet following the backslash.
             *
             *   quoted-pair    = "\" ( HTAB / SP / VCHAR / obs-text )
             */
            static const CharacterSet qPairChars = CharacterSet::HTAB + CharacterSet::SP + CharacterSet::VCHAR + CharacterSet::OBSTEXT;
            SBuf escaped;
            if (!tok.prefix(escaped, qPairChars, 1))
                throw TexcHere("invalid escaped character in quoted-pair");
 
            parsedToken.append(escaped);
            continue;
        }
 
        if (tok.skip('"'))
            return parsedToken; // may be empty
 
        if (tok.atEnd())
            break;
 
        throw TexcHere(ToSBuf("invalid bytes for set ", tokenChars.name));
    }
 
    throw Http::One::InsufficientInput();
}
 
SBuf
Http::One::tokenOrQuotedString(Parser::Tokenizer &tok, const bool http1p0)
{
    if (tok.skip('"'))
        return parseQuotedStringSuffix(tok, http1p0);
 
    if (tok.atEnd())
        throw InsufficientInput();
 
    SBuf parsedToken;
    if (!tok.prefix(parsedToken, CharacterSet::TCHAR))
        throw TexcHere("invalid input while expecting an HTTP token");
 
    if (tok.atEnd())
        throw InsufficientInput();
 
    // got the complete token
    return parsedToken;
}