[PATCH net v3 0/2] xfrm: iptfs: fix queued receive state lifetime

[Roshan Kumar <roshaen09@gmail.com>]

IP-TFS can retain received skbs in its reorder window and reassembly state.
Two lifetime problems interact in these paths: the shared drop timer
does not track the two states independently, and retained skbs do not
keep their input net_device alive.

Patch 1 gives reassembly and reorder state separate deadlines and
always arms their shared timer for the earliest one. Patch 2 holds a
device reference for every retained skb until ordered processing or
destruction is complete.

The unpatched base reproduces the device use-after-free under KASAN.
The final series passes the reorder, reassembly, SA deletion/expiry,
clean teardown, and unprivileged user-namespace regression cases,
including a timer-overlap test for stale deadlines.

Testing on x86-64 at the base commit plus this series:
- KASAN + NET_DEV_REFCNT_TRACKER: the 10-case lifecycle matrix passed on
  both the regular and lockdep/RCU-debug kernels;
- stale-deadline overlap regression: 5.155 second close delay (minimum 4s);
- runt-created reassembly regression: 5.152 second close delay
  (minimum 4s);
- PREEMPT=full, lockdep, RCU, atomic-sleep, debug-object, and ref-tracker
  scans were clean;
- GCC 13.3 and Clang 18.1 W=1 object builds passed;
- x86-32 and arm64 cross-compiled W=1 object builds passed;
- allnoconfig W=1 full build passed;
- allmodconfig and allyesconfig W=1 xfrm_iptfs.o builds passed. The
  full builds stop on the same unrelated lockdep_proc.c and callthunks.c
  GCC diagnostics reproduced on the unpatched base.

Changes in v3:
- split the shared-timer correction into a prerequisite patch;
- keep the reassembly reference through xfrm_input();
- track reassembly and reorder deadlines independently and arm runt-created
  reassembly;
- cover all reorder, completion, abort, timeout, and destruction paths;
- use netdev_hold()/netdev_put() and document reference ownership;
- remove the incorrect bounded-lifetime claim and self Reported-by trailer;
- add the required AI-assistance disclosure.

Changes in v2:
- add reassembly queue coverage and state-destruction cleanup;
- add the Fixes tag and independent reporting team credit.

Roshan Kumar (2):
  xfrm: iptfs: track independent drop deadlines
  xfrm: iptfs: hold a device reference while packets are queued

 net/xfrm/xfrm_iptfs.c | 151 ++++++++++++++++++++++++++++++------------
 1 file changed, 108 insertions(+), 43 deletions(-)


base-commit: a7bfaba4823e3c165bb2004c74eff7c096672bc7
-- 
2.43.0