D8413: Filelight crashes if readdir returns very long file name

[Aleksei Nikiforov]

i.Dark_Templar created this revision.
i.Dark_Templar added reviewers: sitter, kfunk.
Restricted Application added a subscriber: kde-utils-devel.

REVISION SUMMARY
  While it's usually stated that 'struct dirent' has member 'char d_name[PATH_MAX + 1]', it is possible to obtain results when this field contains a string longer than PATH_MAX + 1. Stringbuilder in that case would copy only PATH_MAX + 1 first bytes, and wouldn't add zero terminator to this copied string, which would eventually lead to crash.
  
  How to reproduce:
  
  1. use ntfs filesystem (for example, via ntfs-3g)
  
  Ntfs filesystem uses maximum number of characters for restricting file name length, not bytes, and character may be longer than 1 byte.
  
  2. create a file with name out of > 255 bytes, but less than 255 characters. Use non-ascii characters for that and UTF-8 locale.
  
  It's too long filename for a Linux filesystem, but actually a valid name for ntfs filesystem.
  In my case, I hit a file with name of 166 characters and 264 bytes (not including zero terminator).
  
  3. run filelight on filesystem containing that file and see it crash.
  
  What should happen:
  Filelight should run fine, and if struct dirent::d_name is longer that PATH_MAX, it should work fine with it.

REPOSITORY
  R352 Filelight

REVISION DETAIL
  https://phabricator.kde.org/D8413

AFFECTED FILES
  src/localLister.cpp

To: i.Dark_Templar, sitter, kfunk
Cc: kde-utils-devel
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