Messages in this thread | | | Subject | Re: [PATCH 2/3] tun: free skb in early errors | From | Jason Wang <> | Date | Fri, 1 Dec 2017 15:07:44 +0800 |
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On 2017年12月01日 13:54, wexu@redhat.com wrote: > From: Wei Xu <wexu@redhat.com> > > tun_recvmsg() supports accepting skb by msg_control after > commit ac77cfd4258f ("tun: support receiving skb through msg_control"), > the skb if presented should be freed within the function, otherwise it > would be leaked. > > Signed-off-by: Wei Xu <wexu@redhat.com> > Reported-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com> > --- > drivers/net/tun.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 6a7bde9..5563430 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -2067,14 +2067,17 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, > { > struct tun_file *tfile = container_of(sock, struct tun_file, socket); > struct tun_struct *tun = tun_get(tfile); > + struct sk_buff *skb = m->msg_control; > int ret; > > - if (!tun) > - return -EBADFD; > + if (!tun) { > + ret = -EBADFD; > + goto out_free_skb;
Unfortunately, you can't to there since tun is NULL.
> + } > > if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { > ret = -EINVAL; > - goto out; > + goto out_free_skb; > } > if (flags & MSG_ERRQUEUE) { > ret = sock_recv_errqueue(sock->sk, m, total_len, > @@ -2087,6 +2090,11 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, > m->msg_flags |= MSG_TRUNC; > ret = flags & MSG_TRUNC ? ret : total_len; > } > + goto out;
We usually don't use goto in the case of success, and you need deal with the case skb != NULL but iov_iter_count(to) == 0 in tun_do_read().
Thanks
> + > +out_free_skb: > + if (skb) > + kfree_skb(skb); > out: > tun_put(tun); > return ret;
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