From 653a437c04440495cd8e7712c7cf39444f26f1ee Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Thu, 25 Mar 2021 17:55:20 -0400 Subject: [PATCH] accept_filter: Fix filter parameter handling For filters which implement accf_create, the setsockopt(2) handler caches the filter name in the socket, but it also incorrectly frees the buffer containing the copy, leaving a dangling pointer. Note that no accept filters provided in the base system are susceptible to this, as they don't implement accf_create. Reported by: Alexey Kulaev Discussed with: emaste Security: kernel use-after-free MFC after: 3 days Sponsored by: The FreeBSD Foundation --- sys/kern/uipc_accf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sys/kern/uipc_accf.c b/sys/kern/uipc_accf.c index debf4b2deeb..3ca64dd21e2 100644 --- a/sys/kern/uipc_accf.c +++ b/sys/kern/uipc_accf.c @@ -299,6 +299,7 @@ accept_filt_setopt(struct socket *so, struct sockopt *sopt) so->sol_accept_filter = afp; so->sol_accept_filter_arg = accept_filter_arg; so->sol_accept_filter_str = accept_filter_str; + accept_filter_str = NULL; so->so_options |= SO_ACCEPTFILTER; out: SOCK_UNLOCK(so); -- 2.45.0