int PackUnix::canUnpack()
{
int const small = 32 + sizeof(overlay_offset);
// Allow zero-filled last page, for Mac OS X code signing.
int bufsize = 2*4096 + 2*small +1;
if (bufsize > fi->st_size())
bufsize = fi->st_size();
MemBuffer buf(bufsize);
fi->seek(-(off_t)bufsize, SEEK_END);
fi->readx(buf, bufsize);
int i = bufsize;
while (i > small && 0 == buf[--i]) { }
i -= small;
// allow incompressible extents
if (i < 0 || !getPackHeader(buf + i, bufsize - i, true))
return false;
int l = ph.buf_offset + ph.getPackHeaderSize();
if (l < 0 || l + 4 > bufsize)
throwCantUnpack("file corrupted");
overlay_offset = get_te32(buf + i + l);
if ((off_t)overlay_offset >= file_size)
throwCantUnpack("file corrupted");
return true;
}
int PackUnix::canUnpack()
{
upx_byte buf[sizeof(overlay_offset) + 32];
const int bufsize = sizeof(buf);
fi->seek(-bufsize, SEEK_END);
fi->readx(buf, bufsize);
if (!getPackHeader(buf, bufsize, true)) // allow incompressible extents
return false;
int l = ph.buf_offset + ph.getPackHeaderSize();
if (l < 0 || l + 4 > bufsize)
throwCantUnpack("file corrupted");
overlay_offset = get_te32(buf+l);
if ((off_t)overlay_offset >= file_size)
throwCantUnpack("file corrupted");
return true;
}
