proc_pid_attr(5)              File Formats Manual             proc_pid_attr(5)

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)