From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subash Abhinov Kasiviswanathan Subject: Re: [PATCH net] net: qualcomm: rmnet: Fix a double free Date: Fri, 08 Sep 2017 13:44:52 -0600 Message-ID: <2ddbb6da514108b4e70ccd8362292134@codeaurora.org> References: <20170908102356.tzysh6qaiesd2umz@mwanda> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , netdev@vger.kernel.org, kernel-janitors@vger.kernel.org To: Dan Carpenter Return-path: In-Reply-To: <20170908102356.tzysh6qaiesd2umz@mwanda> Sender: kernel-janitors-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > index 557c9bf1a469..0335fce54201 100644 > --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > @@ -95,10 +95,8 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff > *skb) > skb_pull(skb, packet_len); > > /* Some hardware can send us empty frames. Catch them */ > - if (ntohs(maph->pkt_len) == 0) { > - kfree_skb(skb); > + if (ntohs(maph->pkt_len) == 0) > return NULL; > - } > > return skbn; > } Thanks for the patch. This is fixing the double free, but is leaking the new skb skbn created. Perhaps we should add the check earlier - diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 557c9bf..86b8c75 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -84,6 +84,10 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb) if (((int)skb->len - (int)packet_len) < 0) return NULL; + /* Some hardware can send us empty frames. Catch them */ + if (ntohs(maph->pkt_len) == 0) + return NULL; + skbn = alloc_skb(packet_len + RMNET_MAP_DEAGGR_SPACING, GFP_ATOMIC); if (!skbn) return NULL; @@ -94,11 +98,5 @@ struct sk_buff *rmnet_map_deaggregate(struct sk_buff *skb) memcpy(skbn->data, skb->data, packet_len); skb_pull(skb, packet_len); - /* Some hardware can send us empty frames. Catch them */ - if (ntohs(maph->pkt_len) == 0) { - kfree_skb(skb); - return NULL; - } - return skbn; } -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project