From: Paul Moore <paul@paul-moore.com>
To: Liu Shixin <liushixin2@huawei.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] netlabel: Fix memory leak in netlbl_mgmt_add_common
Date: Thu, 10 Jun 2021 19:38:54 -0400 [thread overview]
Message-ID: <CAHC9VhQM4YP527Z9ijTBk2i++S=viZ1hKVo6GgCOUcNCVgB2vw@mail.gmail.com> (raw)
In-Reply-To: <20210610020108.1356361-1-liushixin2@huawei.com>
On Wed, Jun 9, 2021 at 9:29 PM Liu Shixin <liushixin2@huawei.com> wrote:
>
> Hulk Robot reported memory leak in netlbl_mgmt_add_common.
> The problem is non-freed map in case of netlbl_domhsh_add() failed.
>
> BUG: memory leak
> unreferenced object 0xffff888100ab7080 (size 96):
> comm "syz-executor537", pid 360, jiffies 4294862456 (age 22.678s)
> hex dump (first 32 bytes):
> 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> fe 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 ................
> backtrace:
> [<0000000008b40026>] netlbl_mgmt_add_common.isra.0+0xb2a/0x1b40
> [<000000003be10950>] netlbl_mgmt_add+0x271/0x3c0
> [<00000000c70487ed>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320
> [<000000001f2ff614>] genl_rcv_msg+0x2bf/0x4f0
> [<0000000089045792>] netlink_rcv_skb+0x134/0x3d0
> [<0000000020e96fdd>] genl_rcv+0x24/0x40
> [<0000000042810c66>] netlink_unicast+0x4a0/0x6a0
> [<000000002e1659f0>] netlink_sendmsg+0x789/0xc70
> [<000000006e43415f>] sock_sendmsg+0x139/0x170
> [<00000000680a73d7>] ____sys_sendmsg+0x658/0x7d0
> [<0000000065cbb8af>] ___sys_sendmsg+0xf8/0x170
> [<0000000019932b6c>] __sys_sendmsg+0xd3/0x190
> [<00000000643ac172>] do_syscall_64+0x37/0x90
> [<000000009b79d6dc>] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Fixes: 63c416887437 ("netlabel: Add network address selectors to the NetLabel/LSM domain mapping")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Liu Shixin <liushixin2@huawei.com>
> ---
> net/netlabel/netlabel_mgmt.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
> index e664ab990941..e7f00c0f441e 100644
> --- a/net/netlabel/netlabel_mgmt.c
> +++ b/net/netlabel/netlabel_mgmt.c
> @@ -191,6 +191,12 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
> entry->family = AF_INET;
> entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
> entry->def.addrsel = addrmap;
> +
> + ret_val = netlbl_domhsh_add(entry, audit_info);
> + if (ret_val != 0) {
> + kfree(map);
> + goto add_free_addrmap;
> + }
> #if IS_ENABLED(CONFIG_IPV6)
> } else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) {
> struct in6_addr *addr;
> @@ -243,13 +249,19 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
> entry->family = AF_INET6;
> entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
> entry->def.addrsel = addrmap;
> +
> + ret_val = netlbl_domhsh_add(entry, audit_info);
> + if (ret_val != 0) {
> + kfree(map);
> + goto add_free_addrmap;
> + }
> #endif /* IPv6 */
> + } else {
> + ret_val = netlbl_domhsh_add(entry, audit_info);
> + if (ret_val != 0)
> + goto add_free_addrmap;
> }
>
> - ret_val = netlbl_domhsh_add(entry, audit_info);
> - if (ret_val != 0)
> - goto add_free_addrmap;
> -
> return 0;
Thanks for the report and a fix, although I think there may be a
simpler fix that results in less code duplication; some quick pseudo
code below:
int netlbl_mgmt_add_common(...)
{
void *map_p = NULL;
if (NLBL_MGMT_A_IPV4ADDR) {
struct netlbl_domaddr4_map *map;
map_p = map;
} else if (NLBL_MGMT_A_IPV6ADDR) {
struct netlbl_domaddr4_map *map;
map_p = map;
}
add_free_addrmap:
kfree(map_p);
kfree(addrmap);
}
... this approach would even simplify the error handling after the
netlbl_af{4,6}list_add() calls a bit too (you could jump straight to
add_free_addrmap).
--
paul moore
www.paul-moore.com
next prev parent reply other threads:[~2021-06-10 23:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 2:01 [PATCH -next] netlabel: Fix memory leak in netlbl_mgmt_add_common Liu Shixin
2021-06-10 3:08 ` Dongliang Mu
2021-06-10 10:45 ` Liu Shixin
2021-06-10 12:15 ` Dongliang Mu
2021-06-10 23:38 ` Paul Moore [this message]
2021-06-11 4:05 ` Dongliang Mu
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