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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.
150 lines
3.4 KiB
C++
150 lines
3.4 KiB
C++
#include <qpdf/FileInputSource.hh>
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#include <string.h>
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#include <qpdf/QUtil.hh>
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#include <qpdf/QPDFExc.hh>
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#include <algorithm>
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FileInputSource::FileInputSource() :
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close_file(false),
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file(0)
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{
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}
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void
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FileInputSource::setFilename(char const* filename)
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{
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destroy();
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this->filename = filename;
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this->close_file = true;
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this->file = QUtil::safe_fopen(this->filename.c_str(), "rb");
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}
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void
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FileInputSource::setFile(
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char const* description, FILE* filep, bool close_file)
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{
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destroy();
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this->filename = description;
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this->close_file = close_file;
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this->file = filep;
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this->seek(0, SEEK_SET);
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}
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FileInputSource::~FileInputSource()
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{
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destroy();
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}
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void
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FileInputSource::destroy()
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{
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if (this->file && this->close_file)
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{
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fclose(this->file);
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this->file = 0;
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}
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}
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qpdf_offset_t
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FileInputSource::findAndSkipNextEOL()
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{
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qpdf_offset_t result = 0;
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bool done = false;
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char buf[10240];
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while (! done)
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{
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qpdf_offset_t cur_offset = QUtil::tell(this->file);
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size_t len = this->read(buf, sizeof(buf));
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if (len == 0)
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{
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done = true;
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result = this->tell();
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}
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else
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{
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char* p1 = static_cast<char*>(memchr(buf, '\r', len));
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char* p2 = static_cast<char*>(memchr(buf, '\n', len));
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char* p = (p1 && p2) ? std::min(p1, p2) : p1 ? p1 : p2;
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if (p)
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{
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result = cur_offset + (p - buf);
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// We found \r or \n. Keep reading until we get past
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// \r and \n characters.
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this->seek(result + 1, SEEK_SET);
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char ch;
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while (! done)
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{
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if (this->read(&ch, 1) == 0)
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{
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done = true;
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}
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else if (! ((ch == '\r') || (ch == '\n')))
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{
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this->unreadCh(ch);
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done = true;
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}
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}
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}
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}
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}
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return result;
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}
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std::string const&
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FileInputSource::getName() const
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{
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return this->filename;
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}
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qpdf_offset_t
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FileInputSource::tell()
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{
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return QUtil::tell(this->file);
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}
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void
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FileInputSource::seek(qpdf_offset_t offset, int whence)
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{
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QUtil::os_wrapper(std::string("seek to ") + this->filename + ", offset " +
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QUtil::int_to_string(offset) + " (" +
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QUtil::int_to_string(whence) + ")",
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QUtil::seek(this->file, offset, whence));
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}
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void
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FileInputSource::rewind()
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{
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::rewind(this->file);
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}
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size_t
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FileInputSource::read(char* buffer, size_t length)
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{
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this->last_offset = this->tell();
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size_t len = fread(buffer, 1, length, this->file);
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if (len == 0)
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{
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if (ferror(this->file))
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{
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throw QPDFExc(qpdf_e_system,
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this->filename, "",
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this->last_offset,
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std::string("read ") +
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QUtil::uint_to_string(length) + " bytes");
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}
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else if (length > 0)
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{
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this->seek(0, SEEK_END);
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this->last_offset = this->tell();
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}
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}
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return len;
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}
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void
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FileInputSource::unreadCh(char ch)
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{
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QUtil::os_wrapper(this->filename + ": unread character",
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ungetc(static_cast<unsigned char>(ch), this->file));
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}
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