[PATCH v2 00/15] Rework tty audit

[Peter Hurley]

Changes from v1:
- Fixed build breakage at "tty: audit: Ignore current association for audit push"
  reported by Fengguang's build robot

As noted in the build report, the breakage only impacted bisectability, as
the subsequent patch removed the breakage anyway.

---

Hi Greg,

Here's a resend of the original tty audit series from Nov 10;
no objections from the audit maintainers.

Original message follows:

This patch series overhauls tty audit support. The goal was to simplify
and speed up tty auditing, which was a significant performance hit even
when disabled.

The main features of this series are:
* Remove reference counting; the purpose of reference counting the per-
  process tty_audit_buf was to prevent premature deletion if the
  buffer was in-use when tty auditing was exited for the process.
  However, since the process is single-threaded at tty_audit_exit(),
  the buffer cannot be in-use by another thread. Patch 11/15.
* Remove functionally dead code, such as tty_put_user(). Patch 2/15.
* Atomically modify tty audit enable/disable flags to support lockless
  read. Patch 9/15.

Regards,

Peter Hurley (15):
  tty: audit: Early-out pty master reads earlier
  tty: audit: Never audit packet mode
  tty: audit: Remove icanon mode from call chain
  tty: audit: Defer audit buffer association
  tty: audit: Take siglock directly
  tty: audit: Ignore current association for audit push
  tty: audit: Combine push functions
  tty: audit: Track tty association with dev_t
  tty: audit: Handle tty audit enable atomically
  tty: audit: Remove false memory optimization
  tty: audit: Remove tty_audit_buf reference counting
  tty: audit: Simplify first-use allocation
  tty: audit: Check audit enable first
  tty: audit: Always push audit buffer before TIOCSTI
  tty: audit: Poison tty_audit_buf while process exits

 drivers/tty/n_tty.c     |  25 ++----
 drivers/tty/tty_audit.c | 231 ++++++++++++++----------------------------------
 include/linux/audit.h   |   4 +
 include/linux/sched.h   |   1 -
 include/linux/tty.h     |  12 +--
 kernel/audit.c          |  27 +++---
 6 files changed, 97 insertions(+), 203 deletions(-)

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2.7.0