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netfilter: ctnetlink: use netlink policy range checks

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Replace manual range and mask validations with netlink policy
annotations in ctnetlink code paths, so that the netlink core rejects
invalid values early and can generate extack errors.

- CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at
  policy level, removing the manual >= TCP_CONNTRACK_MAX check.
- CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE
  (14). The normal TCP option parsing path already clamps to this value,
  but the ctnetlink path accepted 0-255, causing undefined behavior when
  used as a u32 shift count.
- CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with
  CTA_FILTER_F_ALL, removing the manual mask checks.
- CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding
  a new mask define grouping all valid expect flags.

Extracted from a broader nf-next patch by Florian Westphal, scoped to
ctnetlink for the fixes tree.

Fixes: c8e2078cfe ("[NETFILTER]: ctnetlink: add support for internal tcp connection tracking flags handling")
Signed-off-by: David Carlier <devnexen@gmail.com>
Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
David Carlier
2026-03-25 14:11:08 +01:00
committed by Pablo Neira Ayuso
parent 6a2b724460
commit 8f15b5071b
3 changed files with 12 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
include/uapi/linux/netfilter/nf_conntrack_common.h
View File

@@ -159,5 +159,9 @@ enum ip_conntrack_expect_events {
#define NF_CT_EXPECT_INACTIVE 0x2
#define NF_CT_EXPECT_USERSPACE 0x4
#ifdef __KERNEL__
#define NF_CT_EXPECT_MASK (NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE | \
NF_CT_EXPECT_USERSPACE)
#endif
#endif /* _UAPI_NF_CONNTRACK_COMMON_H */

16
net/netfilter/nf_conntrack_netlink.c
View File

@@ -910,8 +910,8 @@ struct ctnetlink_filter {
};
static const struct nla_policy cta_filter_nla_policy[CTA_FILTER_MAX + 1] = {
[CTA_FILTER_ORIG_FLAGS] = { .type = NLA_U32 },
[CTA_FILTER_REPLY_FLAGS] = { .type = NLA_U32 },
[CTA_FILTER_ORIG_FLAGS] = NLA_POLICY_MASK(NLA_U32, CTA_FILTER_F_ALL),
[CTA_FILTER_REPLY_FLAGS] = NLA_POLICY_MASK(NLA_U32, CTA_FILTER_F_ALL),
};
static int ctnetlink_parse_filter(const struct nlattr *attr,
@@ -925,17 +925,11 @@ static int ctnetlink_parse_filter(const struct nlattr *attr,
if (ret)
return ret;
if (tb[CTA_FILTER_ORIG_FLAGS]) {
if (tb[CTA_FILTER_ORIG_FLAGS])
filter->orig_flags = nla_get_u32(tb[CTA_FILTER_ORIG_FLAGS]);
if (filter->orig_flags & ~CTA_FILTER_F_ALL)
return -EOPNOTSUPP;
}
if (tb[CTA_FILTER_REPLY_FLAGS]) {
if (tb[CTA_FILTER_REPLY_FLAGS])
filter->reply_flags = nla_get_u32(tb[CTA_FILTER_REPLY_FLAGS]);
if (filter->reply_flags & ~CTA_FILTER_F_ALL)
return -EOPNOTSUPP;
}
return 0;
}
@@ -2634,7 +2628,7 @@ static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = {
[CTA_EXPECT_HELP_NAME] = { .type = NLA_NUL_STRING,
.len = NF_CT_HELPER_NAME_LEN - 1 },
[CTA_EXPECT_ZONE] = { .type = NLA_U16 },
[CTA_EXPECT_FLAGS] = { .type = NLA_U32 },
[CTA_EXPECT_FLAGS] = NLA_POLICY_MASK(NLA_BE32, NF_CT_EXPECT_MASK),
[CTA_EXPECT_CLASS] = { .type = NLA_U32 },
[CTA_EXPECT_NAT] = { .type = NLA_NESTED },
[CTA_EXPECT_FN] = { .type = NLA_NUL_STRING },

10
net/netfilter/nf_conntrack_proto_tcp.c
View File

@@ -1385,9 +1385,9 @@ nla_put_failure:
}
static const struct nla_policy tcp_nla_policy[CTA_PROTOINFO_TCP_MAX+1] = {
[CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 },
[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
[CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 },
[CTA_PROTOINFO_TCP_STATE] = NLA_POLICY_MAX(NLA_U8, TCP_CONNTRACK_SYN_SENT2),
[CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = NLA_POLICY_MAX(NLA_U8, TCP_MAX_WSCALE),
[CTA_PROTOINFO_TCP_WSCALE_REPLY] = NLA_POLICY_MAX(NLA_U8, TCP_MAX_WSCALE),
[CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .len = sizeof(struct nf_ct_tcp_flags) },
[CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .len = sizeof(struct nf_ct_tcp_flags) },
};
@@ -1414,10 +1414,6 @@ static int nlattr_to_tcp(struct nlattr *cda[], struct nf_conn *ct)
if (err < 0)
return err;
if (tb[CTA_PROTOINFO_TCP_STATE] &&
nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]) >= TCP_CONNTRACK_MAX)
return -EINVAL;
spin_lock_bh(&ct->lock);
if (tb[CTA_PROTOINFO_TCP_STATE])
ct->proto.tcp.state = nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]);