Thread (3 messages) 3 messages, 3 authors, 2010-12-31

Re: [PATCH] ISDN, Gigaset: Fix memory leak in do_disconnect_req()

From: Tilman Schmidt <hidden>
Date: 2010-12-28 17:42:43
Also in: lkml

Quite correct. Thanks for finding and fixing this.

Am 26.12.2010 20:59 schrieb Jesper Juhl:
Hi,

In drivers/isdn/gigaset/capi.c::do_disconnect_req() we will leak the 
memory allocated (with kmalloc) to 'b3cmsg' if the call to alloc_skb() 
fails.

...
		b3cmsg = kmalloc(sizeof(*b3cmsg), GFP_KERNEL);
	allocation here ------^
		if (!b3cmsg) {
			dev_err(cs->dev, "%s: out of memory\n", __func__);
			send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
			return;
		}
		capi_cmsg_header(b3cmsg, ap->id, CAPI_DISCONNECT_B3, CAPI_IND,
				 ap->nextMessageNumber++,
				 cmsg->adr.adrPLCI | (1 << 16));
		b3cmsg->Reason_B3 = CapiProtocolErrorLayer1;
		b3skb = alloc_skb(CAPI_DISCONNECT_B3_IND_BASELEN, GFP_KERNEL);
		if (b3skb == NULL) {
			dev_err(cs->dev, "%s: out of memory\n", __func__);
			send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
			return;
	leak here ------^
...

This leak is easily fixed by just kfree()'ing the memory allocated to 
'b3cmsg' right before we return. The following patch does that.


Signed-off-by: Jesper Juhl <redacted>
Acked-by: Tilman Schmidt <redacted>
quoted hunk ↗ jump to hunk
---
 capi.c |    1 +
 1 file changed, 1 insertion(+)

  compile tested only since I have no way to actually test this.
diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index bcc174e..658e75f 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -1900,6 +1900,7 @@ static void do_disconnect_req(struct gigaset_capi_ctr *iif,
 		if (b3skb == NULL) {
 			dev_err(cs->dev, "%s: out of memory\n", __func__);
 			send_conf(iif, ap, skb, CAPI_MSGOSRESOURCEERR);
+			kfree(b3cmsg);
 			return;
 		}
 		capi_cmsg2message(b3cmsg,
-- 
Tilman Schmidt                    E-Mail: tilman@imap.cc
Bonn, Germany
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