lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:	Sat, 18 Oct 2014 19:21:24 +0400
From:	Dmitry Monakhov <>
Cc:,,, Dmitry Monakhov <>
Subject: [PATCH 0/4] fs: fcntl/fadvice fixes v2

fcntl(F_SETFL) and fadvise performs direct manipulation with file's internals.
w/o notifying to fs layer. This behavior be not be suitable for some filesystems
(mostly stack-fs like ecryptfs, unionfs, etc). Let's introduce new ->set_flags()
callback for that purpose. This callback is responsible for flags check so
->check_flags() no longer required.

 fs: fcntl add set_flags wrapper -v2
 fs: add fadvise file_operation
 ecryptfs: add fadvise/set_flags calbacks
 cifs: add set_flag callback

This series does not fix all issues related with set_flags.
Race between fcntl(toggling O_DIRECT) vs write() is still possible
Usually O_DIRECT checked twice during call chain:
So we may end-up up with two different values. Some filesystems (btrfs/xfs)
avoid this issue by copy-pasting __generic_file_write_iter.
One of possible way to fix this issue it to save flags in kiocb->ki_flags
as we already do with ->ki_pos. And fixup all places accordingly.
I've calculated numbers of direct access to ->f_flags it is close to 150,
half of that number is ->open() methods. So patch would not be gigantic.
And finally here is my question to AlViro and Christoph and other VFS-people:
*Are you agree with that approach?* Please say your word.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists