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Message-Id: <20210114163822.56306-1-xiyou.wangcong@gmail.com>
Date: Thu, 14 Jan 2021 08:38:22 -0800
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: Cong Wang <cong.wang@...edance.com>,
syzbot+2624e3778b18fc497c92@...kaller.appspotmail.com,
Jamal Hadi Salim <jhs@...atatu.com>,
Xin Long <lucien.xin@...il.com>, Jiri Pirko <jiri@...nulli.us>,
Jakub Kicinski <kuba@...nel.org>
Subject: [Patch net v2] cls_flower: call nla_ok() before nla_next()
From: Cong Wang <cong.wang@...edance.com>
fl_set_enc_opt() simply checks if there are still bytes left to parse,
but this is not sufficent as syzbot seems to be able to generate
malformatted netlink messages. nla_ok() is more strict so should be
used to validate the next nlattr here.
And nla_validate_nested_deprecated() has less strict check too, it is
probably too late to switch to the strict version, but we can just
call nla_ok() too after it.
Reported-and-tested-by: syzbot+2624e3778b18fc497c92@...kaller.appspotmail.com
Fixes: 0a6e77784f49 ("net/sched: allow flower to match tunnel options")
Fixes: 79b1011cb33d ("net: sched: allow flower to match erspan options")
Cc: Jamal Hadi Salim <jhs@...atatu.com>
Cc: Xin Long <lucien.xin@...il.com>
Cc: Jiri Pirko <jiri@...nulli.us>
Cc: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Cong Wang <cong.wang@...edance.com>
---
net/sched/cls_flower.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 1319986693fc..740d9018e45f 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1272,6 +1272,10 @@ static int fl_set_enc_opt(struct nlattr **tb, struct fl_flow_key *key,
nla_opt_msk = nla_data(tb[TCA_FLOWER_KEY_ENC_OPTS_MASK]);
msk_depth = nla_len(tb[TCA_FLOWER_KEY_ENC_OPTS_MASK]);
+ if (!nla_ok(nla_opt_msk, msk_depth)) {
+ NL_SET_ERR_MSG(extack, "Invalid attribute for masks");
+ return -EINVAL;
+ }
}
nla_for_each_attr(nla_opt_key, nla_enc_key,
@@ -1307,9 +1311,6 @@ static int fl_set_enc_opt(struct nlattr **tb, struct fl_flow_key *key,
NL_SET_ERR_MSG(extack, "Key and mask miss aligned");
return -EINVAL;
}
-
- if (msk_depth)
- nla_opt_msk = nla_next(nla_opt_msk, &msk_depth);
break;
case TCA_FLOWER_KEY_ENC_OPTS_VXLAN:
if (key->enc_opts.dst_opt_type) {
@@ -1340,9 +1341,6 @@ static int fl_set_enc_opt(struct nlattr **tb, struct fl_flow_key *key,
NL_SET_ERR_MSG(extack, "Key and mask miss aligned");
return -EINVAL;
}
-
- if (msk_depth)
- nla_opt_msk = nla_next(nla_opt_msk, &msk_depth);
break;
case TCA_FLOWER_KEY_ENC_OPTS_ERSPAN:
if (key->enc_opts.dst_opt_type) {
@@ -1373,14 +1371,17 @@ static int fl_set_enc_opt(struct nlattr **tb, struct fl_flow_key *key,
NL_SET_ERR_MSG(extack, "Key and mask miss aligned");
return -EINVAL;
}
-
- if (msk_depth)
- nla_opt_msk = nla_next(nla_opt_msk, &msk_depth);
break;
default:
NL_SET_ERR_MSG(extack, "Unknown tunnel option type");
return -EINVAL;
}
+
+ if (!nla_ok(nla_opt_msk, msk_depth)) {
+ NL_SET_ERR_MSG(extack, "Mask attribute is invalid");
+ return -EINVAL;
+ }
+ nla_opt_msk = nla_next(nla_opt_msk, &msk_depth);
}
return 0;
--
2.25.1
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