Re: [PATCH] net: ipv4: fix memory leak in netlbl_cipsov4_add_std

From: Paul Moore <paul@paul-moore.com>
To: Nanyong Sun <sunnanyong@huawei.com>
Cc: davem@davemloft.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org,
	kuba@kernel.org, netdev@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: ipv4: fix memory leak in netlbl_cipsov4_add_std
Date: Mon, 7 Jun 2021 21:53:55 -0400	[thread overview]
Message-ID: <CAHC9VhTqDjN1VwakrYZznaMVTyqkEKcYLo=bPtHsOXugS_mexQ@mail.gmail.com> (raw)
In-Reply-To: <20210608015158.3848878-1-sunnanyong@huawei.com>

On Mon, Jun 7, 2021 at 9:19 PM Nanyong Sun <sunnanyong@huawei.com> wrote:
>
> Reported by syzkaller:
> BUG: memory leak
> unreferenced object 0xffff888105df7000 (size 64):
> comm "syz-executor842", pid 360, jiffies 4294824824 (age 22.546s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<00000000e67ed558>] kmalloc include/linux/slab.h:590 [inline]
> [<00000000e67ed558>] kzalloc include/linux/slab.h:720 [inline]
> [<00000000e67ed558>] netlbl_cipsov4_add_std net/netlabel/netlabel_cipso_v4.c:145 [inline]
> [<00000000e67ed558>] netlbl_cipsov4_add+0x390/0x2340 net/netlabel/netlabel_cipso_v4.c:416
> [<0000000006040154>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320 net/netlink/genetlink.c:739
> [<00000000204d7a1c>] genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
> [<00000000204d7a1c>] genl_rcv_msg+0x2bf/0x4f0 net/netlink/genetlink.c:800
> [<00000000c0d6a995>] netlink_rcv_skb+0x134/0x3d0 net/netlink/af_netlink.c:2504
> [<00000000d78b9d2c>] genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
> [<000000009733081b>] netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
> [<000000009733081b>] netlink_unicast+0x4a0/0x6a0 net/netlink/af_netlink.c:1340
> [<00000000d5fd43b8>] netlink_sendmsg+0x789/0xc70 net/netlink/af_netlink.c:1929
> [<000000000a2d1e40>] sock_sendmsg_nosec net/socket.c:654 [inline]
> [<000000000a2d1e40>] sock_sendmsg+0x139/0x170 net/socket.c:674
> [<00000000321d1969>] ____sys_sendmsg+0x658/0x7d0 net/socket.c:2350
> [<00000000964e16bc>] ___sys_sendmsg+0xf8/0x170 net/socket.c:2404
> [<000000001615e288>] __sys_sendmsg+0xd3/0x190 net/socket.c:2433
> [<000000004ee8b6a5>] do_syscall_64+0x37/0x90 arch/x86/entry/common.c:47
> [<00000000171c7cee>] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> The memory of doi_def->map.std pointing is allocated in
> netlbl_cipsov4_add_std, but no place has freed it. It should be
> freed in cipso_v4_doi_free which frees the cipso DOI resource.
>
> Fixes: 96cb8e3313c7a ("[NetLabel]: CIPSOv4 and Unlabeled packet integration")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
> ---
>  net/ipv4/cipso_ipv4.c | 1 +
>  1 file changed, 1 insertion(+)

Nice catch, thanks for fixing this.

Acked-by: Paul Moore <paul@paul-moore.com>

> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index d6e3a92841e3..099259fc826a 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -471,6 +471,7 @@ void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
>                 kfree(doi_def->map.std->lvl.local);
>                 kfree(doi_def->map.std->cat.cipso);
>                 kfree(doi_def->map.std->cat.local);
> +               kfree(doi_def->map.std);
>                 break;
>         }
>         kfree(doi_def);
> --
> 2.18.0.huawei.25

-- 
paul moore
www.paul-moore.com