This is a note to let you know that I've just added the patch titled
net/sched: sch_fq: fix integer overflow of "credit"
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-sched-sch_fq-fix-integer-overflow-of-credit.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2ac40ee9bede0ce4d94267f00855cd664980d1df
Author: Davide Caratti <dcaratti@xxxxxxxxxx>
Date: Thu Apr 20 16:59:46 2023 +0200
net/sched: sch_fq: fix integer overflow of "credit"
[ Upstream commit 7041101ff6c3073fd8f2e99920f535b111c929cb ]
if sch_fq is configured with "initial quantum" having values greater than
INT_MAX, the first assignment of "credit" does signed integer overflow to
a very negative value.
In this situation, the syzkaller script provided by Cristoph triggers the
CPU soft-lockup warning even with few sockets. It's not an infinite loop,
but "credit" wasn't probably meant to be minus 2Gb for each new flow.
Capping "initial quantum" to INT_MAX proved to fix the issue.
v2: validation of "initial quantum" is done in fq_policy, instead of open
coding in fq_change() _ suggested by Jakub Kicinski
Reported-by: Christoph Paasch <cpaasch@xxxxxxxxx>
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/377
Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler")
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx>
Link: https://lore.kernel.org/r/7b3a3c7e36d03068707a021760a194a8eb5ad41a.1682002300.git.dcaratti@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 2fb76fc0cc31b..5a1274199fe33 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -779,13 +779,17 @@ static int fq_resize(struct Qdisc *sch, u32 log)
return 0;
}
+static struct netlink_range_validation iq_range = {
+ .max = INT_MAX,
+};
+
static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
[TCA_FQ_UNSPEC] = { .strict_start_type = TCA_FQ_TIMER_SLACK },
[TCA_FQ_PLIMIT] = { .type = NLA_U32 },
[TCA_FQ_FLOW_PLIMIT] = { .type = NLA_U32 },
[TCA_FQ_QUANTUM] = { .type = NLA_U32 },
- [TCA_FQ_INITIAL_QUANTUM] = { .type = NLA_U32 },
+ [TCA_FQ_INITIAL_QUANTUM] = NLA_POLICY_FULL_RANGE(NLA_U32, &iq_range),
[TCA_FQ_RATE_ENABLE] = { .type = NLA_U32 },
[TCA_FQ_FLOW_DEFAULT_RATE] = { .type = NLA_U32 },
[TCA_FQ_FLOW_MAX_RATE] = { .type = NLA_U32 },
