[PATCH v3 0/2] Restrict dangerous open in sticky directories

[Salvatore Mesoraca <s.mesoraca16@gmail.com>]

This patch-set introduces two separate features aimed at restricting
dangerous open in world or group writable sticky directories.
The purpose is to prevent exploitable bugs in user-space programs
that don't access sticky directories in the proper way.
The first patch prevents the O_CREAT open of FIFOs and regular files
in world or group writable sticky directories, if they already exists
and are owned by someone else.
The second patch prevents O_CREAT open in world or group writable
sticky when the O_EXCL flag is not set, even if the file doesn't
exist yet.
More details can be found in the respective commit messages.

Changes in v3:
	- Fixed format string for uid_t that is unsigned
	  (suggested by Jann Horn).
	- Stop checking if file's and parent dir's owners match in
	  may_create_no_excl. This will allow to discover potential
	  vulnerabilities more easily.

Salvatore Mesoraca (2):
  Protected FIFOs and regular files
  Protected O_CREAT open in sticky directories

 Documentation/sysctl/fs.txt |  66 +++++++++++++++++++++++++
 fs/namei.c                  | 117 ++++++++++++++++++++++++++++++++++++++++++--
 include/linux/fs.h          |   3 ++
 kernel/sysctl.c             |  27 ++++++++++
 4 files changed, 210 insertions(+), 3 deletions(-)

-- 
1.9.1