Re: [Info-mtools] Bug: File or directory is lost after renaming it to "Õtest"

[Pali Rohár]

Hi! More then half of year passed... It would be nice to have fixed
version of mtools which address this problem. I also sent proposed
patches which are ready for review.

On Saturday 30 December 2017 18:24:12 David C Niemi wrote:
> Just got back from a little vacation. I was hoping to hear from Alain
> Knaff.  Given your information it should be easy enough to fix, but creating
> a proper release is not something I can do easily.
> 
> David
> 
> On 12/30/2017 08:09 AM, Pali Rohár wrote:
> > Hi David! Any progress on this problem?
> > 
> > On Sunday 19 November 2017 09:04:19 David C Niemi wrote:
> > > Thanks for your diligent analysis of the problem.  I probably introduced
> > > that bug back in about 1994...
> > > 
> > > Will need help from Alain to get this fix into a release.
> > > 
> > > David
> > > 
> > > On 11/17/2017 01:00 PM, Pali Rohár wrote:
> > > > Hi! More mtools programs (mlabel, mcopy, mdir) do not handle correctly
> > > > file names which starts with 0x05 or 0xE5 byte.
> > > > 
> > > > In FAT specification is written:
> > > > 
> > > >    * If DIR_Name[0] == 0xE5, then the directory entry is free (there is 
> > > > no
> > > >      file or directory name in this entry).
> > > > 
> > > >    * If DIR_Name[0] == 0x05, then the actual file name character for 
> > > > this
> > > >      byte is 0xE5.
> > > > 
> > > > Byte 0xE5 in CP850 is character 'Õ'. So if I try to create file which
> > > > starts with 'Õ', then mtools should convert 'Õ' to DOS codepage and if
> > > > it is 0xE5 then change it to 0x05.
> > > > 
> > > > But mtools does not change 0xE5 to 0x05 which leads to create orphaned
> > > > file. Test case for empty FAT filesystem:
> > > > 
> > > > $ echo test | mcopy - ::Õtest -i fat
> > > > $ mdir :: -i fat
> > > > Directory for ::/
> > > > No files
> > > > 
> > > > It is even worse when you try to rename directory to new name which
> > > > would start with 'Õ' character. After running mren the whole directory
> > > > which its content is lost:
> > > > 
> > > > $ mmd ::test -i fat
> > > > $ mdir :: -i fat
> > > > Directory for ::/
> > > > test         <DIR>     2017-11-17  18:46  test
> > > > $ mren ::test ::Õtest -i fat
> > > > $ mdir :: -i fat
> > > > Directory for ::/
> > > > No files
> > > > 
> > > > The problem is that mtools does not handle 0xE5 byte correctly and allow
> > > > user directly to damage directories entries.
> > > > 
> > > > Another program mlabel has exactly same problem:
> > > > 
> > > > $ mlabel ::test -i fat
> > > > $ mlabel -s ::test -i fat
> > > >    Volume label is TEST
> > > > $ mlabel ::Õtest -i fat
> > > > $ mlabel -s ::test -i fat
> > > >    Volume has no label
> > > > 
> > > > In attachment I'm sending fix for this bug.
> > > > 
> > > 
> 

-- 
Pali Rohár
address@hidden