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Groups > linux.kernel > #1507638 > unrolled thread

[PATCH] can: fix warning in bcm_connect/proc_register

Started byOliver Hartkopp <socketcan@hartkopp.net>
First post2016-10-24 21:20 +0200
Last post2016-10-24 22:20 +0200
Articles 4 — 3 participants

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  [PATCH] can: fix warning in bcm_connect/proc_register Oliver Hartkopp <socketcan@hartkopp.net> - 2016-10-24 21:20 +0200
    Re: [PATCH] can: fix warning in bcm_connect/proc_register Cong Wang <xiyou.wangcong@gmail.com> - 2016-10-24 22:20 +0200
      Re: [PATCH] can: fix warning in bcm_connect/proc_register Andrey Konovalov <andreyknvl@google.com> - 2016-10-25 14:20 +0200
    Re: [PATCH] can: fix warning in bcm_connect/proc_register Cong Wang <xiyou.wangcong@gmail.com> - 2016-10-24 22:20 +0200

#1507638 — [PATCH] can: fix warning in bcm_connect/proc_register

FromOliver Hartkopp <socketcan@hartkopp.net>
Date2016-10-24 21:20 +0200
Subject[PATCH] can: fix warning in bcm_connect/proc_register
Message-ID<svSWR-3rd-21@gated-at.bofh.it>
Andrey Konovalov reported an issue with proc_register in bcm.c.
As suggested by Cong Wang this patch adds a lock_sock() protection and
a check for unsuccessful proc_create_data() in bcm_connect().

Reference: http://marc.info/?l=linux-netdev&m=147732648731237

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 net/can/bcm.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 8e999ff..8af9d25 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1549,24 +1549,31 @@ static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
 	struct sock *sk = sock->sk;
 	struct bcm_sock *bo = bcm_sk(sk);
+	int ret = 0;
 
 	if (len < sizeof(*addr))
 		return -EINVAL;
 
-	if (bo->bound)
-		return -EISCONN;
+	lock_sock(sk);
+
+	if (bo->bound) {
+		ret = -EISCONN;
+		goto fail;
+	}
 
 	/* bind a device to this socket */
 	if (addr->can_ifindex) {
 		struct net_device *dev;
 
 		dev = dev_get_by_index(&init_net, addr->can_ifindex);
-		if (!dev)
-			return -ENODEV;
-
+		if (!dev) {
+			ret = -ENODEV;
+			goto fail;
+		}
 		if (dev->type != ARPHRD_CAN) {
 			dev_put(dev);
-			return -ENODEV;
+			ret = -ENODEV;
+			goto fail;
 		}
 
 		bo->ifindex = dev->ifindex;
@@ -1577,17 +1584,24 @@ static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
 		bo->ifindex = 0;
 	}
 
-	bo->bound = 1;
-
 	if (proc_dir) {
 		/* unique socket address as filename */
 		sprintf(bo->procname, "%lu", sock_i_ino(sk));
 		bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
 						     proc_dir,
 						     &bcm_proc_fops, sk);
+		if (!bo->bcm_proc_read) {
+			ret = -ENOMEM;
+			goto fail;
+		}
 	}
 
-	return 0;
+	bo->bound = 1;
+
+fail:
+	release_sock(sk);
+
+	return ret;
 }
 
 static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
-- 
2.9.3

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#1507686

FromCong Wang <xiyou.wangcong@gmail.com>
Date2016-10-24 22:20 +0200
Message-ID<svTSV-43c-1@gated-at.bofh.it>
In reply to#1507638
On Mon, Oct 24, 2016 at 1:10 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> On Mon, Oct 24, 2016 at 12:11 PM, Oliver Hartkopp
> <socketcan@hartkopp.net> wrote:
>>         if (proc_dir) {
>>                 /* unique socket address as filename */
>>                 sprintf(bo->procname, "%lu", sock_i_ino(sk));
>>                 bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
>>                                                      proc_dir,
>>                                                      &bcm_proc_fops, sk);
>> +               if (!bo->bcm_proc_read) {
>> +                       ret = -ENOMEM;
>> +                       goto fail;
>> +               }
>
> Well, I meant we need to call proc_create_data() once per socket,
> so we need a check before proc_create_data() too.

Hmm, bo->bound should guarantee it, so never mind, your patch
looks fine.

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#1508249

FromAndrey Konovalov <andreyknvl@google.com>
Date2016-10-25 14:20 +0200
Message-ID<sw8RY-5yg-11@gated-at.bofh.it>
In reply to#1507686
Hi Oliver,

I can confirm that your patch fixes the warnings for me.

Tested-by: Andrey Konovalov <andreyknvl@google.com>

On Mon, Oct 24, 2016 at 10:17 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> On Mon, Oct 24, 2016 at 1:10 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
>> On Mon, Oct 24, 2016 at 12:11 PM, Oliver Hartkopp
>> <socketcan@hartkopp.net> wrote:
>>>         if (proc_dir) {
>>>                 /* unique socket address as filename */
>>>                 sprintf(bo->procname, "%lu", sock_i_ino(sk));
>>>                 bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
>>>                                                      proc_dir,
>>>                                                      &bcm_proc_fops, sk);
>>> +               if (!bo->bcm_proc_read) {
>>> +                       ret = -ENOMEM;
>>> +                       goto fail;
>>> +               }
>>
>> Well, I meant we need to call proc_create_data() once per socket,
>> so we need a check before proc_create_data() too.
>
> Hmm, bo->bound should guarantee it, so never mind, your patch
> looks fine.

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#1507688

FromCong Wang <xiyou.wangcong@gmail.com>
Date2016-10-24 22:20 +0200
Message-ID<svTSV-43c-3@gated-at.bofh.it>
In reply to#1507638
On Mon, Oct 24, 2016 at 12:11 PM, Oliver Hartkopp
<socketcan@hartkopp.net> wrote:
>         if (proc_dir) {
>                 /* unique socket address as filename */
>                 sprintf(bo->procname, "%lu", sock_i_ino(sk));
>                 bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
>                                                      proc_dir,
>                                                      &bcm_proc_fops, sk);
> +               if (!bo->bcm_proc_read) {
> +                       ret = -ENOMEM;
> +                       goto fail;
> +               }

Well, I meant we need to call proc_create_data() once per socket,
so we need a check before proc_create_data() too.

Thanks.

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