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: 211da42eaa45 ("net, neigh: introduce interval_probe_time_ms for periodic probe") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Ido Schimmel --- Currently, the sysctl range check is not applied to interval_probe_time_ms, which needs this fix: https://lore.kernel.org/linux-fsdevel/20260905233819.1064529-2-kuniyu@google.com/ Cc: Yuwei Wang v3: * Nest min/max inside checks: in rt-neigh.yaml v2: * Clarify the attribute is for NTF_MANAGED * Update docs, rt-neigh.yaml and ip-sysctl.rst --- Documentation/netlink/specs/rt-neigh.yaml | 3 +++ Documentation/networking/ip-sysctl.rst | 2 +- net/core/neighbour.c | 17 +++++++++++++---- 3 files changed, 17 insertions(+), 5 deletions(-) diff --git a/Documentation/netlink/specs/rt-neigh.yaml b/Documentation/netlink/specs/rt-neigh.yaml index 0f46ef313590..c8e55c98d564 100644 --- a/Documentation/netlink/specs/rt-neigh.yaml +++ b/Documentation/netlink/specs/rt-neigh.yaml @@ -341,6 +341,9 @@ attribute-sets: - name: interval-probe-time-ms type: u64 + checks: + min: 1 + max: 86400000 operations: enum-model: directional diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 208f46967ee5..b05829e44d8f 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -248,7 +248,7 @@ neigh/default/unres_qlen - INTEGER neigh/default/interval_probe_time_ms - INTEGER The probe interval for neighbor entries with NTF_MANAGED flag, - the min value is 1. + the min value is 1, and the max value is 86400000 (1 day). Default: 5000 diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 49dd7df149ef..0db78a0dfb51 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -2359,6 +2359,13 @@ static const struct nla_policy nl_neightbl_policy[NDTA_MAX+1] = { [NDTA_PARMS] = { .type = NLA_NESTED }, }; +#define NTBL_PARM_MS_MAX (24 * 60 * 60 * MSEC_PER_SEC) + +static const struct netlink_range_validation nl_ntbl_parm_ms_range = { + .min = 1, + .max = NTBL_PARM_MS_MAX, +}; + static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = { [NDTPA_IFINDEX] = { .type = NLA_U32 }, [NDTPA_QUEUE_LEN] = { .type = NLA_U32 }, @@ -2375,7 +2382,8 @@ static const struct nla_policy nl_ntbl_parm_policy[NDTPA_MAX+1] = { [NDTPA_ANYCAST_DELAY] = { .type = NLA_U64 }, [NDTPA_PROXY_DELAY] = { .type = NLA_U64 }, [NDTPA_LOCKTIME] = { .type = NLA_U64 }, - [NDTPA_INTERVAL_PROBE_TIME_MS] = { .type = NLA_U64, .min = 1 }, + [NDTPA_INTERVAL_PROBE_TIME_MS] = NLA_POLICY_FULL_RANGE(NLA_U64, + &nl_ntbl_parm_ms_range), }; static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, @@ -3672,12 +3680,13 @@ static int neigh_proc_dointvec_ms_jiffies_positive(const struct ctl_table *ctl, void *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table tmp = *ctl; - int ret; + int ret, min, max; - int min = msecs_to_jiffies(1); + min = msecs_to_jiffies(1); + max = msecs_to_jiffies(NTBL_PARM_MS_MAX); tmp.extra1 = &min; - tmp.extra2 = NULL; + tmp.extra2 = &max; ret = proc_dointvec_ms_jiffies_minmax(&tmp, write, buffer, lenp, ppos); neigh_proc_update(ctl, write); -- 2.55.0.1003.g10538fe699-goog