[PATCH 0/4] NFS: harden pNFS device address decoding

[Prabhakar Pujeri <prabhakar.pujeri@dell.com>]

pNFS GETDEVICEINFO replies contain server-provided universal addresses
and multipath counts. The current decoders accept malformed port octets
and can spend billions of iterations on a count that is not bounded by
the reply length.

Patch 1 validates both decimal port octets. Patches 2 and 3 bound the
file-layout and flexfiles multipath loops by the minimum XDR space needed
for each remaining netaddr4. Patch 4 adds focused KUnit coverage.

This series is based on the NFS client linux-next integration commit
10f307e525a1, as published in next-20260821.

Tested on a Dell PowerEdge R660: the pNFS decoder KUnit suite passed
16/16 and the flexfiles suite passed 3/3, with an empty kmemleak scan.
No pNFS-capable server was available, so the affected decoder paths were
exercised directly by KUnit.

NFSv3, v4.1, and v4.2 data, locking, and parallel workloads passed,
together with NFSv3 ACL and NFSv4.2 xattr checks. The series builds
cleanly with GCC and Clang W=1 and passes Sparse C=2. Strict checkpatch
is clean


Prabhakar Pujeri (4):
  NFS: validate pNFS data server port octets
  NFS: bound multipath address count in file-layout GETDEVICEINFO
  NFS: bound multipath address count in flexfiles GETDEVICEINFO
  NFS: add KUnit coverage for pNFS address decoding

 fs/nfs/Kconfig                               |  34 +++
 fs/nfs/Makefile                              |   3 +
 fs/nfs/filelayout/filelayoutdev.c            |   5 +
 fs/nfs/flexfilelayout/Makefile               |   3 +
 fs/nfs/flexfilelayout/flexfilelayoutdev.c    |   9 +
 fs/nfs/flexfilelayout/tests/deviceid_kunit.c | 188 ++++++++++++++++
 fs/nfs/pnfs.h                                |   8 +
 fs/nfs/pnfs_nfs.c                            |  47 ++--
 fs/nfs/tests/pnfs_decode_kunit.c             | 222 +++++++++++++++++++
 9 files changed, 500 insertions(+), 19 deletions(-)
 create mode 100644 fs/nfs/flexfilelayout/tests/deviceid_kunit.c
 create mode 100644 fs/nfs/tests/pnfs_decode_kunit.c


base-commit: 10f307e525a1783570a39eb9ac146d45f4f16b3e
-- 
2.54.0