[PATCH nf] netfilter: x_tables: ensure names are nul-terminated

[Florian Westphal <fw@strlen.de>]

Reject names that lack a \0 character before feeding them
to functions that expect c-strings.

Fixes tag is the most recent commit that needs this change.

Fixes: c38c4597e4bf ("netfilter: implement xt_cgroup cgroup2 path match")
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/xt_cgroup.c  |  6 ++++++
 net/netfilter/xt_physdev.c | 10 ++++++++++
 net/netfilter/xt_rateest.c |  5 +++++
 3 files changed, 21 insertions(+)

diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c
index c437fbd59ec1..43d2ae2be628 100644
--- a/net/netfilter/xt_cgroup.c
+++ b/net/netfilter/xt_cgroup.c
@@ -65,6 +65,9 @@ static int cgroup_mt_check_v1(const struct xt_mtchk_param *par)
 
 	info->priv = NULL;
 	if (info->has_path) {
+		if (strnlen(info->path, sizeof(info->path)) >= sizeof(info->path))
+			return -ENAMETOOLONG;
+
 		cgrp = cgroup_get_from_path(info->path);
 		if (IS_ERR(cgrp)) {
 			pr_info_ratelimited("invalid path, errno=%ld\n",
@@ -102,6 +105,9 @@ static int cgroup_mt_check_v2(const struct xt_mtchk_param *par)
 
 	info->priv = NULL;
 	if (info->has_path) {
+		if (strnlen(info->path, sizeof(info->path)) >= sizeof(info->path))
+			return -ENAMETOOLONG;
+
 		cgrp = cgroup_get_from_path(info->path);
 		if (IS_ERR(cgrp)) {
 			pr_info_ratelimited("invalid path, errno=%ld\n",
diff --git a/net/netfilter/xt_physdev.c b/net/netfilter/xt_physdev.c
index 343e65f377d4..1b522a181a8d 100644
--- a/net/netfilter/xt_physdev.c
+++ b/net/netfilter/xt_physdev.c
@@ -107,6 +107,16 @@ static int physdev_mt_check(const struct xt_mtchk_param *par)
 		return -EINVAL;
 	}
 
+#define X(memb) strnlen(info->memb , sizeof(info->memb)) >= sizeof(info->memb)
+	if (X(physindev))
+		return -ENAMETOOLONG;
+	if (X(physoutdev))
+		return -ENAMETOOLONG;
+	if (X(in_mask))
+		return -ENAMETOOLONG;
+	if (X(out_mask))
+		return -ENAMETOOLONG;
+#undef X
 	if (!brnf_probed) {
 		brnf_probed = true;
 		request_module("br_netfilter");
diff --git a/net/netfilter/xt_rateest.c b/net/netfilter/xt_rateest.c
index 72324bd976af..b1d736c15fcb 100644
--- a/net/netfilter/xt_rateest.c
+++ b/net/netfilter/xt_rateest.c
@@ -91,6 +91,11 @@ static int xt_rateest_mt_checkentry(const struct xt_mtchk_param *par)
 		goto err1;
 	}
 
+	if (strnlen(info->name1, sizeof(info->name1)) >= sizeof(info->name1))
+		return -ENAMETOOLONG;
+	if (strnlen(info->name2, sizeof(info->name2)) >= sizeof(info->name2))
+		return -ENAMETOOLONG;
+
 	ret  = -ENOENT;
 	est1 = xt_rateest_lookup(par->net, info->name1);
 	if (!est1)
-- 
2.53.0