[syslinux] Patch: Fix isohybrid.c tool under Windows platforms
Ady Ady
ady-sf at hotmail.com
Mon Apr 17 02:51:17 PDT 2017
> Hi,
>
> Colin Finck wrote:
> > Precisely, if isohybrid currently finds a 0x0A (LF) byte in the MBR code
> > (which exists in the strings), it adds a 0x0D (CR) before, thereby
> > shifting the MBR bytes to the right and making it invalid.
> > This can be fixed by opening the file in binary mode with the "b" flag.
>
> This is a very reasonable proposal.
> If one wants the same behavior of fread(3) and fwrite(3) on descendants of
> Unix and DOS, then one should in any case add "b" to the fopen(3) mode
> string.
>
> Not only MBR writing but also reading of the Primary Volume Descriptor
> and of the El Torito catalog by isohybrid.c are currently prone to
> unwanted CR-insertion. Miscalculations can be caused by this.
Is there anything that can be done in order to reduce such chances of
miscalculation and/or unwanted insertion of (CR) characters?
>
> The fopen() call for reading external MBR code (option -m) already has "b".
>
> The old perl code contains a call to function binmode, which does about
> the same as C fopen(3) with "b" in the mode string.
So, is there any reason not to apply the suggested patch? Any potential
compatibility issues? Backward compatibility between different versions
of isohybrid and isolinux.bin? Anything?
>
>
> Have a nice day :)
>
> Thomas
>
Regards,
Ady.
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