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https://github.com/qpdf/qpdf.git
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d71f05ca07
This makes all integer type conversions that have potential data loss explicit with calls that do range checks and raise an exception. After this commit, qpdf builds with no warnings when -Wsign-conversion -Wconversion is used with gcc or clang or when -W3 -Wd4800 is used with MSVC. This significantly reduces the likelihood of potential crashes from bogus integer values. There are some parts of the code that take int when they should take size_t or an offset. Such places would make qpdf not support files with more than 2^31 of something that usually wouldn't be so large. In the event that such a file shows up and is valid, at least qpdf would raise an error in the right spot so the issue could be legitimately addressed rather than failing in some weird way because of a silent overflow condition.
134 lines
2.2 KiB
C++
134 lines
2.2 KiB
C++
#include <qpdf/Pl_ASCII85Decoder.hh>
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#include <qpdf/QTC.hh>
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#include <stdexcept>
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#include <string.h>
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Pl_ASCII85Decoder::Pl_ASCII85Decoder(char const* identifier, Pipeline* next) :
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Pipeline(identifier, next),
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pos(0),
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eod(0)
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{
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memset(this->inbuf, 117, 5);
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}
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Pl_ASCII85Decoder::~Pl_ASCII85Decoder()
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{
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}
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void
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Pl_ASCII85Decoder::write(unsigned char* buf, size_t len)
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{
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if (eod > 1)
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{
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return;
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}
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for (size_t i = 0; i < len; ++i)
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{
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if (eod > 1)
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{
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break;
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}
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else if (eod == 1)
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{
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if (buf[i] == '>')
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{
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flush();
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eod = 2;
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}
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else
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{
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throw std::runtime_error(
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"broken end-of-data sequence in base 85 data");
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}
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}
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else
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{
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switch (buf[i])
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{
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case ' ':
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case '\f':
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case '\v':
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case '\t':
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case '\r':
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case '\n':
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QTC::TC("libtests", "Pl_ASCII85Decoder ignore space");
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// ignore whitespace
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break;
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case '~':
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eod = 1;
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break;
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case 'z':
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if (pos != 0)
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{
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throw std::runtime_error(
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"unexpected z during base 85 decode");
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}
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else
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{
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QTC::TC("libtests", "Pl_ASCII85Decoder read z");
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unsigned char zeroes[4];
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memset(zeroes, '\0', 4);
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getNext()->write(zeroes, 4);
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}
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break;
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default:
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if ((buf[i] < 33) || (buf[i] > 117))
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{
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throw std::runtime_error(
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"character out of range during base 85 decode");
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}
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else
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{
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this->inbuf[this->pos++] = buf[i];
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if (pos == 5)
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{
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flush();
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}
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}
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break;
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}
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}
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}
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}
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void
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Pl_ASCII85Decoder::flush()
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{
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if (this->pos == 0)
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{
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QTC::TC("libtests", "Pl_ASCII85Decoder no-op flush");
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return;
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}
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unsigned long lval = 0;
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for (int i = 0; i < 5; ++i)
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{
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lval *= 85;
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lval += (this->inbuf[i] - 33U);
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}
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unsigned char outbuf[4];
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memset(outbuf, 0, 4);
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for (int i = 3; i >= 0; --i)
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{
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outbuf[i] = lval & 0xff;
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lval >>= 8;
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}
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QTC::TC("libtests", "Pl_ASCII85Decoder partial flush",
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(this->pos == 5) ? 0 : 1);
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getNext()->write(outbuf, this->pos - 1);
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this->pos = 0;
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memset(this->inbuf, 117, 5);
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}
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void
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Pl_ASCII85Decoder::finish()
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{
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flush();
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getNext()->finish();
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}
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