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Sat, 23 Sep 2023 23:03:31 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFzc6g2VxeSFFA1pRFagT5GtyabcUKpPjtAq/MWnCPL9Fy7EZYFoZ69r6Dscmbis/qAG507ig== X-Received: by 2002:a17:90b:4c92:b0:25d:eca9:1621 with SMTP id my18-20020a17090b4c9200b0025deca91621mr2156633pjb.6.1695535410990; Sat, 23 Sep 2023 23:03:30 -0700 (PDT) Received: from kernel-devel.local ([240d:1a:c0d:9f00:245e:16ff:fe87:c960]) by smtp.gmail.com with ESMTPSA id ki19-20020a17090ae91300b0026b41363887sm7516644pjb.27.2023.09.23.23.03.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 23 Sep 2023 23:03:30 -0700 (PDT) From: Shigeru Yoshida To: jmaloy@redhat.com, ying.xue@windriver.com Cc: netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org, Shigeru Yoshida , syzbot+5138ca807af9d2b42574@syzkaller.appspotmail.com Subject: [PATCH] tipc: Fix uninit-value access in tipc_nl_node_reset_link_stats() Date: Sun, 24 Sep 2023 15:03:25 +0900 Message-ID: <20230924060325.3779150-1-syoshida@redhat.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" syzbot reported the following uninit-value access issue: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D BUG: KMSAN: uninit-value in strlen lib/string.c:418 [inline] BUG: KMSAN: uninit-value in strstr+0xb8/0x2f0 lib/string.c:756 strlen lib/string.c:418 [inline] strstr+0xb8/0x2f0 lib/string.c:756 tipc_nl_node_reset_link_stats+0x3ea/0xb50 net/tipc/node.c:2595 genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline] genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066 netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545 genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg net/socket.c:753 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2541 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2595 __sys_sendmsg net/socket.c:2624 [inline] __do_sys_sendmsg net/socket.c:2633 [inline] __se_sys_sendmsg net/socket.c:2631 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was created at: slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:559 __alloc_skb+0x318/0x740 net/core/skbuff.c:650 alloc_skb include/linux/skbuff.h:1286 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline] netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg net/socket.c:753 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2541 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2595 __sys_sendmsg net/socket.c:2624 [inline] __do_sys_sendmsg net/socket.c:2633 [inline] __se_sys_sendmsg net/socket.c:2631 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Link names must be null-terminated strings. If a link name which is not null-terminated is passed through netlink, strstr() and similar functions can cause buffer overrun. This causes the above issue. This patch fixes this issue by returning -EINVAL if a non-null-terminated link name is passed. Fixes: ae36342b50a9 ("tipc: add link stat reset to new netlink api") Reported-and-tested-by: syzbot+5138ca807af9d2b42574@syzkaller.appspotmail.c= om Closes: https://syzkaller.appspot.com/bug?extid=3D5138ca807af9d2b42574 Signed-off-by: Shigeru Yoshida Acked-by: Jon Maloy --- net/tipc/node.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/tipc/node.c b/net/tipc/node.c index 3105abe97bb9..f167bdafc034 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -2586,6 +2586,10 @@ int tipc_nl_node_reset_link_stats(struct sk_buff *sk= b, struct genl_info *info) =20 link_name =3D nla_data(attrs[TIPC_NLA_LINK_NAME]); =20 + if (link_name[strnlen(link_name, + nla_len(attrs[TIPC_NLA_LINK_NAME]))] !=3D '\0') + return -EINVAL; + err =3D -EINVAL; if (!strcmp(link_name, tipc_bclink_name)) { err =3D tipc_bclink_reset_stats(net, tipc_bc_sndlink(net)); --=20 2.41.0