Provided by: manpages_6.9.1-1_all 
NAME
/proc/pid/attr/ - security-related attributes
DESCRIPTION
/proc/pid/attr/
The files in this directory provide an API for security modules. The contents of this directory
are files that can be read and written in order to set security-related attributes. This
directory was added to support SELinux, but the intention was that the API be general enough to
support other security modules. For the purpose of explanation, examples of how SELinux uses
these files are provided below.
This directory is present only if the kernel was configured with CONFIG_SECURITY.
/proc/pid/attr/current (since Linux 2.6.0)
The contents of this file represent the current security attributes of the process.
In SELinux, this file is used to get the security context of a process. Prior to Linux 2.6.11,
this file could not be used to set the security context (a write was always denied), since SELinux
limited process security transitions to execve(2) (see the description of /proc/pid/attr/exec,
below). Since Linux 2.6.11, SELinux lifted this restriction and began supporting "set" operations
via writes to this node if authorized by policy, although use of this operation is only suitable
for applications that are trusted to maintain any desired separation between the old and new
security contexts.
Prior to Linux 2.6.28, SELinux did not allow threads within a multithreaded process to set their
security context via this node as it would yield an inconsistency among the security contexts of
the threads sharing the same memory space. Since Linux 2.6.28, SELinux lifted this restriction
and began supporting "set" operations for threads within a multithreaded process if the new
security context is bounded by the old security context, where the bounded relation is defined in
policy and guarantees that the new security context has a subset of the permissions of the old
security context.
Other security modules may choose to support "set" operations via writes to this node.
/proc/pid/attr/exec (since Linux 2.6.0)
This file represents the attributes to assign to the process upon a subsequent execve(2).
In SELinux, this is needed to support role/domain transitions, and execve(2) is the preferred
point to make such transitions because it offers better control over the initialization of the
process in the new security label and the inheritance of state. In SELinux, this attribute is
reset on execve(2) so that the new program reverts to the default behavior for any execve(2) calls
that it may make. In SELinux, a process can set only its own /proc/pid/attr/exec attribute.
/proc/pid/attr/fscreate (since Linux 2.6.0)
This file represents the attributes to assign to files created by subsequent calls to open(2),
mkdir(2), symlink(2), and mknod(2)
SELinux employs this file to support creation of a file (using the aforementioned system calls) in
a secure state, so that there is no risk of inappropriate access being obtained between the time
of creation and the time that attributes are set. In SELinux, this attribute is reset on
execve(2), so that the new program reverts to the default behavior for any file creation calls it
may make, but the attribute will persist across multiple file creation calls within a program
unless it is explicitly reset. In SELinux, a process can set only its own /proc/pid/attr/fscreate
attribute.
/proc/pid/attr/keycreate (since Linux 2.6.18)
If a process writes a security context into this file, all subsequently created keys (add_key(2))
will be labeled with this context. For further information, see the kernel source file
Documentation/security/keys/core.rst (or file Documentation/security/keys.txt between Linux 3.0
and Linux 4.13, or Documentation/keys.txt before Linux 3.0).
/proc/pid/attr/prev (since Linux 2.6.0)
This file contains the security context of the process before the last execve(2); that is, the
previous value of /proc/pid/attr/current.
/proc/pid/attr/socketcreate (since Linux 2.6.18)
If a process writes a security context into this file, all subsequently created sockets will be
labeled with this context.
SEE ALSO
proc(5)
Linux man-pages 6.9.1 2024-05-02 proc_pid_attr(5)