| From | Ben Hutchings <> | Date | Mon, 06 Nov 2017 23:03:02 +0000 | Subject | [PATCH 3.16 155/294] l2tp: initialise session's refcount before making it reachable |
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3.16.50-rc1 review patch. If anyone has any objections, please let me know.
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From: Guillaume Nault <g.nault@alphalink.fr>
commit 9ee369a405c57613d7c83a3967780c3e30c52ecc upstream.
Sessions must be fully initialised before calling l2tp_session_add_to_tunnel(). Otherwise, there's a short time frame where partially initialised sessions can be accessed by external users.
Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net> [bwh: Backported to 3.16: keep using l2tp_session_inc_refcount()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/l2tp/l2tp_core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1929,6 +1929,8 @@ struct l2tp_session *l2tp_session_create l2tp_session_set_header_len(session, tunnel->version); + l2tp_session_inc_refcount(session); + err = l2tp_session_add_to_tunnel(tunnel, session); if (err) { kfree(session); @@ -1936,10 +1938,6 @@ struct l2tp_session *l2tp_session_create return ERR_PTR(err); } - /* Bump the reference count. The session context is deleted - * only when this drops to zero. - */ - l2tp_session_inc_refcount(session); l2tp_tunnel_inc_refcount(tunnel); /* Ensure tunnel socket isn't deleted */
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