[PATCH 5.4 140/154] netlabel: Fix NULL pointer exception caused by CALIPSO on IPv4 sockets

Greg Kroah-Hartman
2025-04-08T12:08:30Z

From: Debin Zhu <mowenroot@163.com>

[ Upstream commit 078aabd567de3d63d37d7673f714e309d369e6e2 ]

When calling netlbl_conn_setattr(), addr->sa_family is used
to determine the function behavior. If sk is an IPv4 socket,
but the connect function is called with an IPv6 address,
the function calipso_sock_setattr() is triggered.
Inside this function, the following code is executed:

sk_fullsock(__sk) ? inet_sk(__sk)->pinet6 : NULL;

Since sk is an IPv4 socket, pinet6 is NULL, leading to a
null pointer dereference.

This patch fixes the issue by checking if inet6_sk(sk)
returns a NULL pointer before accessing pinet6.

Signed-off-by: Debin Zhu <mowenroot@163.com>
Signed-off-by: Bitao Ouyang <1985755126@qq.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Fixes: ceba1832b1b2 ("calipso: Set the calipso socket label to match the secattr.")
Link: https://patch.msgid.link/20250401124018.4763-1-mowenroot@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv6/calipso.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c
index 7426e33686d13..9bc612b3f8340 100644
--- a/net/ipv6/calipso.c
+++ b/net/ipv6/calipso.c
@@ -1075,8 +1075,13 @@ static int calipso_sock_getattr(struct sock *sk,
struct ipv6_opt_hdr *hop;
int opt_len, len, ret_val = -ENOMSG, offset;
unsigned char *opt;
- struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
+ struct ipv6_pinfo *pinfo = inet6_sk(sk);
+ struct ipv6_txoptions *txopts;
+
+ if (!pinfo)
+ return -EAFNOSUPPORT;

+ txopts = txopt_get(pinfo);
if (!txopts || !txopts->hopopt)
goto done;

@@ -1128,8 +1133,13 @@ static int calipso_sock_setattr(struct sock *sk,
{
int ret_val;
struct ipv6_opt_hdr *old, *new;
- struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
+ struct ipv6_pinfo *pinfo = inet6_sk(sk);
+ struct ipv6_txoptions *txopts;
+
+ if (!pinfo)
+ return -EAFNOSUPPORT;

+ txopts = txopt_get(pinfo);
old = NULL;
if (txopts)
old = txopts->hopopt;
@@ -1156,8 +1166,13 @@ static int calipso_sock_setattr(struct sock *sk,
static void calipso_sock_delattr(struct sock *sk)
{
struct ipv6_opt_hdr *new_hop;
- struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
+ struct ipv6_pinfo *pinfo = inet6_sk(sk);
+ struct ipv6_txoptions *txopts;
+
+ if (!pinfo)
+ return;

+ txopts = txopt_get(pinfo);
if (!txopts || !txopts->hopopt)
goto done;

--
2.39.5