diff mbox series

[net] calipso: Fix memory leak in netlbl_calipso_add_pass()

Message ID 20231122135242.2779058-1-Ilia.Gavrilov@infotecs.ru (mailing list archive)
State Changes Requested
Delegated to: Paul Moore
Headers show
Series [net] calipso: Fix memory leak in netlbl_calipso_add_pass() | expand

Commit Message

Gavrilov Ilia Nov. 22, 2023, 1:55 p.m. UTC 
If IPv6 support is disabled at boot (ipv6.disable=1),
the calipso_init() -> netlbl_calipso_ops_register() function isn't called,
and the netlbl_calipso_ops_get() function always returns NULL.
In this case, the netlbl_calipso_add_pass() function allocates memory
for the doi_def variable but doesn't free it with the calipso_doi_free().

BUG: memory leak
unreferenced object 0xffff888011d68180 (size 64):
  comm "syz-executor.1", pid 10746, jiffies 4295410986 (age 17.928s)
  hex dump (first 32 bytes):
    00 00 00 00 02 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:
    [<00000000730d8770>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000730d8770>] netlbl_calipso_add_pass net/netlabel/netlabel_calipso.c:76 [inline]
    [<00000000730d8770>] netlbl_calipso_add+0x22e/0x4f0 net/netlabel/netlabel_calipso.c:111
    [<0000000002e662c0>] genl_family_rcv_msg_doit+0x22f/0x330 net/netlink/genetlink.c:739
    [<00000000a08d6d74>] genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
    [<00000000a08d6d74>] genl_rcv_msg+0x341/0x5a0 net/netlink/genetlink.c:800
    [<0000000098399a97>] netlink_rcv_skb+0x14d/0x440 net/netlink/af_netlink.c:2515
    [<00000000ff7db83b>] genl_rcv+0x29/0x40 net/netlink/genetlink.c:811
    [<000000000cf53b8c>] netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
    [<000000000cf53b8c>] netlink_unicast+0x54b/0x800 net/netlink/af_netlink.c:1339
    [<00000000d78cd38b>] netlink_sendmsg+0x90a/0xdf0 net/netlink/af_netlink.c:1934
    [<000000008328a57f>] sock_sendmsg_nosec net/socket.c:651 [inline]
    [<000000008328a57f>] sock_sendmsg+0x157/0x190 net/socket.c:671
    [<000000007b65a1b5>] ____sys_sendmsg+0x712/0x870 net/socket.c:2342
    [<0000000083da800e>] ___sys_sendmsg+0xf8/0x170 net/socket.c:2396
    [<000000004a9b827f>] __sys_sendmsg+0xea/0x1b0 net/socket.c:2429
    [<0000000061b64d3a>] do_syscall_64+0x30/0x40 arch/x86/entry/common.c:46
    [<00000000a1265347>] entry_SYSCALL_64_after_hwframe+0x61/0xc6

Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with Syzkaller

Fixes: cb72d38211ea ("netlabel: Initial support for the CALIPSO netlink protocol.")
Signed-off-by: Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru>
---
 net/netlabel/netlabel_calipso.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Paul Moore Nov. 22, 2023, 3:56 p.m. UTC | #1 
On Wed, Nov 22, 2023 at 8:55 AM Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru> wrote:
>
> If IPv6 support is disabled at boot (ipv6.disable=1),
> the calipso_init() -> netlbl_calipso_ops_register() function isn't called,
> and the netlbl_calipso_ops_get() function always returns NULL.
> In this case, the netlbl_calipso_add_pass() function allocates memory
> for the doi_def variable but doesn't free it with the calipso_doi_free().

It looks like a better option would be to return an error code in
netlbl_calipso_add() so we never allocate the memory in the first
place.

Untested patch below, copy-n-paste'd so there is likely whitespace
damage, but you get the idea.

diff --git a/net/netlabel/netlabel_calipso.c b/net/netlabel/netlabel_calipso.c
index f1d5b8465217..26a504dc6e57 100644
--- a/net/netlabel/netlabel_calipso.c
+++ b/net/netlabel/netlabel_calipso.c
@@ -54,8 +54,31 @@ static const struct nla_policy
calipso_genl_policy[NLBL_CALIPSO_A_MAX + 1] = {
       [NLBL_CALIPSO_A_MTYPE] = { .type = NLA_U32 },
};

+static const struct netlbl_calipso_ops *calipso_ops;
+
+/**
+ * netlbl_calipso_ops_register - Register the CALIPSO operations
+ * @ops: ops to register
+ *
+ * Description:
+ * Register the CALIPSO packet engine operations.
+ *
+ */
+const struct netlbl_calipso_ops *
+netlbl_calipso_ops_register(const struct netlbl_calipso_ops *ops)
+{
+       return xchg(&calipso_ops, ops);
+}
+EXPORT_SYMBOL(netlbl_calipso_ops_register);
+
+static const struct netlbl_calipso_ops *netlbl_calipso_ops_get(void)
+{
+       return READ_ONCE(calipso_ops);
+}
+
/* NetLabel Command Handlers
 */
+
/**
 * netlbl_calipso_add_pass - Adds a CALIPSO pass DOI definition
 * @info: the Generic NETLINK info block
@@ -100,10 +123,13 @@ static int netlbl_calipso_add(struct sk_buff
*skb, struct genl_info *info)
{
       int ret_val = -EINVAL;
       struct netlbl_audit audit_info;
+       const struct netlbl_calipso_ops *ops = netlbl_calipso_ops_get();

       if (!info->attrs[NLBL_CALIPSO_A_DOI] ||
           !info->attrs[NLBL_CALIPSO_A_MTYPE])
               return -EINVAL;
+       if (!ops)
+               return -EOPNOTSUPP;

       netlbl_netlink_auditinfo(&audit_info);
       switch (nla_get_u32(info->attrs[NLBL_CALIPSO_A_MTYPE])) {
@@ -363,28 +389,6 @@ int __init netlbl_calipso_genl_init(void)
       return genl_register_family(&netlbl_calipso_gnl_family);
}

-static const struct netlbl_calipso_ops *calipso_ops;
-
-/**
- * netlbl_calipso_ops_register - Register the CALIPSO operations
- * @ops: ops to register
- *
- * Description:
- * Register the CALIPSO packet engine operations.
- *
- */
-const struct netlbl_calipso_ops *
-netlbl_calipso_ops_register(const struct netlbl_calipso_ops *ops)
-{
-       return xchg(&calipso_ops, ops);
-}
-EXPORT_SYMBOL(netlbl_calipso_ops_register);
-
-static const struct netlbl_calipso_ops *netlbl_calipso_ops_get(void)
-{
-       return READ_ONCE(calipso_ops);
-}
-
/**
 * calipso_doi_add - Add a new DOI to the CALIPSO protocol engine
 * @doi_def: the DOI structure
Gavrilov Ilia Nov. 23, 2023, 7:55 a.m. UTC | #2 
On 11/22/23 18:56, Paul Moore wrote:
> On Wed, Nov 22, 2023 at 8:55 AM Gavrilov Ilia <Ilia.Gavrilov@infotecs.ru> wrote:
>>
>> If IPv6 support is disabled at boot (ipv6.disable=1),
>> the calipso_init() -> netlbl_calipso_ops_register() function isn't called,
>> and the netlbl_calipso_ops_get() function always returns NULL.
>> In this case, the netlbl_calipso_add_pass() function allocates memory
>> for the doi_def variable but doesn't free it with the calipso_doi_free().
> 
> It looks like a better option would be to return an error code in
> netlbl_calipso_add() so we never allocate the memory in the first
> place.
> 
> Untested patch below, copy-n-paste'd so there is likely whitespace
> damage, but you get the idea.
> 
> diff --git a/net/netlabel/netlabel_calipso.c b/net/netlabel/netlabel_calipso.c
> index f1d5b8465217..26a504dc6e57 100644
> --- a/net/netlabel/netlabel_calipso.c
> +++ b/net/netlabel/netlabel_calipso.c
> @@ -54,8 +54,31 @@ static const struct nla_policy
> calipso_genl_policy[NLBL_CALIPSO_A_MAX + 1] = {
>         [NLBL_CALIPSO_A_MTYPE] = { .type = NLA_U32 },
> };
> 
> +static const struct netlbl_calipso_ops *calipso_ops;
> +
> +/**
> + * netlbl_calipso_ops_register - Register the CALIPSO operations
> + * @ops: ops to register
> + *
> + * Description:
> + * Register the CALIPSO packet engine operations.
> + *
> + */
> +const struct netlbl_calipso_ops *
> +netlbl_calipso_ops_register(const struct netlbl_calipso_ops *ops)
> +{
> +       return xchg(&calipso_ops, ops);
> +}
> +EXPORT_SYMBOL(netlbl_calipso_ops_register);
> +
> +static const struct netlbl_calipso_ops *netlbl_calipso_ops_get(void)
> +{
> +       return READ_ONCE(calipso_ops);
> +}
> +
> /* NetLabel Command Handlers
>   */
> +
> /**
>   * netlbl_calipso_add_pass - Adds a CALIPSO pass DOI definition
>   * @info: the Generic NETLINK info block
> @@ -100,10 +123,13 @@ static int netlbl_calipso_add(struct sk_buff
> *skb, struct genl_info *info)
> {
>         int ret_val = -EINVAL;
>         struct netlbl_audit audit_info;
> +       const struct netlbl_calipso_ops *ops = netlbl_calipso_ops_get();
> 
>         if (!info->attrs[NLBL_CALIPSO_A_DOI] ||
>             !info->attrs[NLBL_CALIPSO_A_MTYPE])
>                 return -EINVAL;
> +       if (!ops)
> +               return -EOPNOTSUPP;
> 
>         netlbl_netlink_auditinfo(&audit_info);
>         switch (nla_get_u32(info->attrs[NLBL_CALIPSO_A_MTYPE])) {
> @@ -363,28 +389,6 @@ int __init netlbl_calipso_genl_init(void)
>         return genl_register_family(&netlbl_calipso_gnl_family);
> }
> 
> -static const struct netlbl_calipso_ops *calipso_ops;
> -
> -/**
> - * netlbl_calipso_ops_register - Register the CALIPSO operations
> - * @ops: ops to register
> - *
> - * Description:
> - * Register the CALIPSO packet engine operations.
> - *
> - */
> -const struct netlbl_calipso_ops *
> -netlbl_calipso_ops_register(const struct netlbl_calipso_ops *ops)
> -{
> -       return xchg(&calipso_ops, ops);
> -}
> -EXPORT_SYMBOL(netlbl_calipso_ops_register);
> -
> -static const struct netlbl_calipso_ops *netlbl_calipso_ops_get(void)
> -{
> -       return READ_ONCE(calipso_ops);
> -}
> -
> /**
>   * calipso_doi_add - Add a new DOI to the CALIPSO protocol engine
>   * @doi_def: the DOI structure
> 

Thank you for review. I'll test and send this idea in the next version.
diff mbox series

Patch

diff --git a/net/netlabel/netlabel_calipso.c b/net/netlabel/netlabel_calipso.c
index f1d5b8465217..76ae57c4df90 100644
--- a/net/netlabel/netlabel_calipso.c
+++ b/net/netlabel/netlabel_calipso.c
@@ -423,6 +423,8 @@  void calipso_doi_free(struct calipso_doi *doi_def)
 
 	if (ops)
 		ops->doi_free(doi_def);
+	else
+		kfree(doi_def);
 }
 
 /**