Commit b87b6194 authored Feb 21, 2018 by Jason A. Donenfeld Committed by David S. Miller Feb 22, 2018

netlink: put module reference if dump start fails



Before, if cb->start() failed, the module reference would never be put,
because cb->cb_running is intentionally false at this point. Users are
generally annoyed by this because they can no longer unload modules that
leak references. Also, it may be possible to tediously wrap a reference
counter back to zero, especially since module.c still uses atomic_inc
instead of refcount_inc.

This patch expands the error path to simply call module_put if
cb->start() fails.

Fixes: 41c87425 ("netlink: do not set cb_running if dump's start() errs")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent cfd092f2

net/netlink/af_netlink.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2308,7 +2308,7 @@ int __netlink_dump_start(struct sock ssk, struct sk_buff skb,
		if (cb->start) {
		ret = cb->start(cb);
		if (ret)
		goto error_unlock;
		goto error_put;
		}

		nlk->cb_running = true;
		@@ -2328,6 +2328,8 @@ int __netlink_dump_start(struct sock ssk, struct sk_buff skb,
		*/
		return -EINTR;

		error_put:
		module_put(control->module);
		error_unlock:
		sock_put(sk);
		mutex_unlock(nlk->cb_mutex);

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