Re: [PATCH v2] netlink: do not proceed if dump's start() errs
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: 2017-09-28 10:40:10
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On Thu, Sep 28, 2017 at 12:41:44AM +0200, Jason A. Donenfeld wrote:
quoted hunk ↗ jump to hunk
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 327807731b44..94c11cf0459d 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c@@ -2270,10 +2270,13 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, mutex_unlock(nlk->cb_mutex); + ret = 0; if (cb->start) - cb->start(cb); + ret = cb->start(cb); + + if (!ret) + ret = netlink_dump(sk); - ret = netlink_dump(sk); sock_put(sk); if (ret)
FYI, using this horrific hack to currently work around bug:
#define KERNEL_VERSION_THAT_HAS_NETLINK_START_FIX KERNEL_VERSION(4, 14, 0) /* Hopefully! */
static int get(struct sk_buff *skb, struct netlink_callback *cb)
{
#if LINUX_VERSION_CODE < KERNEL_VERSION_THAT_HAS_NETLINK_START_FIX
/* https://marc.info/?l=linux-netdev&m=150655213004221&w=2 */
if (!cb->args[0]) {
ret = get_start(cb);
if (ret)
return ret;
}
#endif
...
}
static const struct genl_ops genl_ops[] = {
{
.cmd = CMD_GET,
#if LINUX_VERSION_CODE >= KERNEL_VERSION_THAT_HAS_NETLINK_START_FIX
/* https://marc.info/?l=linux-netdev&m=150655213004221&w=2 */
.start = get_start,
#endif
.dumpit = get,
...
}
}
Gross.