linux/Documentation/netlink
Kuniyuki Iwashima 6d79b223ec neighbour: Enforce min/max to NDTPA_INTERVAL_PROBE_TIME_MS.
NDTPA_INTERVAL_PROBE_TIME_MS sets .type and .min but misses
.validation_type, so no validation is applied:

  # ynl --family rt-neigh --do setneightbl \
  --json '{"name": "arp_cache", "parms": {"interval-probe-time-ms": 0}}'

  # ynl --family rt-neigh --dump getneightbl --output-json | \
  jq '.[] | select(.name == "arp_cache" and has("config"))
          | .parms["interval-probe-time-ms"]'
  0

Moreover, nla_get_msecs() uses msecs_to_jiffies(), and u64 is
silently cast to u32, so a larger value can bypass the min check:

  e.g. 4294967296 == 0x100000000

  # ynl --family rt-neigh --do setneightbl \
  --json '{"name": "arp_cache", "parms": {"interval-probe-time-ms": 4294967296}}'

  # ynl --family rt-neigh --dump getneightbl --output-json | \
  jq '.[] | select(.name == "arp_cache" and has("config"))
          | .parms["interval-probe-time-ms"]'
  0

msecs_to_jiffies() returns MAX_JIFFY_OFFSET if the value is
larger than INT_MAX.  Also, INT_MAX ms overflows int NEIGH_VAR()
when HZ > 1000 (Alpha, MIPS), and passing a negative integer to
queue_delayed_work(unsigned long delay) causes sign extension,
which wraps around the expiry time to the past, resulting in it
being handled as 0 delay in the timer wheel.

Let's use NLA_POLICY_FULL_RANGE() and limit the max to 1 day.

The same max check is applied to sysctl as well.

Note that this controls the probe interval for NTF_MANAGED
entries, so the max of 1 day is unlikely to break any
deployments.

Fixes: 211da42eaa ("net, neigh: introduce interval_probe_time_ms for periodic probe")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260909233143.2401847-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-09-11 17:25:13 -07:00
..
specs neighbour: Enforce min/max to NDTPA_INTERVAL_PROBE_TIME_MS. 2026-09-11 17:25:13 -07:00
genetlink-c.yaml tools: ynl: add scope qualifier for definitions 2026-05-12 16:15:00 +02:00
genetlink-legacy.yaml tools: ynl: add scope qualifier for definitions 2026-05-12 16:15:00 +02:00
genetlink.yaml tools: ynl: add scope qualifier for definitions 2026-05-12 16:15:00 +02:00
netlink-raw.yaml tools: ynl: add scope qualifier for definitions 2026-05-12 16:15:00 +02:00