From: David Baum <davidbaum461@gmail•com>
To: pablo@netfilter•org, fw@strlen•de
Cc: phil@nwl•cc, davem@davemloft•net, edumazet@google•com,
kuba@kernel•org, pabeni@redhat•com, horms@kernel•org,
netfilter-devel@vger•kernel.org, coreteam@netfilter•org,
netdev@vger•kernel.org, David Baum <davidbaum461@gmail•com>
Subject: [PATCH] netfilter: ipset: harden payload calculation in call_ad()
Date: Fri, 13 Mar 2026 13:01:32 -0500 [thread overview]
Message-ID: <20260313180132.75655-1-davidbaum461@gmail.com> (raw)
call_ad() computes the netlink error payload size with
min(SIZE_MAX, sizeof(*errmsg) + nlmsg_len(nlh)), but min(SIZE_MAX, x)
is always x, so the guard is a no-op.
Replace it with an explicit negative-length check and
check_add_overflow() so the addition is validated before being passed
to nlmsg_new().
Signed-off-by: David Baum <davidbaum461@gmail•com>
---
net/netfilter/ipset/ip_set_core.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index a2fe711cb5e3..11d3854d9b11 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ip.h>
+#include <linux/overflow.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/rculist.h>
@@ -1763,13 +1764,18 @@ call_ad(struct net *net, struct sock *ctnl, struct sk_buff *skb,
struct nlmsghdr *rep, *nlh = nlmsg_hdr(skb);
struct sk_buff *skb2;
struct nlmsgerr *errmsg;
- size_t payload = min(SIZE_MAX,
- sizeof(*errmsg) + nlmsg_len(nlh));
+ int nlmsg_payload_len = nlmsg_len(nlh);
+ size_t payload;
int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
struct nlattr *cda[IPSET_ATTR_CMD_MAX + 1];
struct nlattr *cmdattr;
u32 *errline;
+ if (nlmsg_payload_len < 0 ||
+ check_add_overflow(sizeof(*errmsg),
+ (size_t)nlmsg_payload_len, &payload))
+ return -ENOMEM;
+
skb2 = nlmsg_new(payload, GFP_KERNEL);
if (!skb2)
return -ENOMEM;
--
2.50.1 (Apple Git-155)
next reply other threads:[~2026-03-13 18:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-13 18:01 David Baum [this message]
2026-04-10 1:05 ` [PATCH] netfilter: ipset: harden payload calculation in call_ad() Pablo Neira Ayuso
2026-04-10 1:19 ` Pablo Neira Ayuso
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260313180132.75655-1-davidbaum461@gmail.com \
--to=davidbaum461@gmail$(echo .)com \
--cc=coreteam@netfilter$(echo .)org \
--cc=davem@davemloft$(echo .)net \
--cc=edumazet@google$(echo .)com \
--cc=fw@strlen$(echo .)de \
--cc=horms@kernel$(echo .)org \
--cc=kuba@kernel$(echo .)org \
--cc=netdev@vger$(echo .)kernel.org \
--cc=netfilter-devel@vger$(echo .)kernel.org \
--cc=pabeni@redhat$(echo .)com \
--cc=pablo@netfilter$(echo .)org \
--cc=phil@nwl$(echo .)cc \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox