From nobody Sat May 3 08:14:26 2025 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4ZqLDM1Nd7z5twMT; Sat, 03 May 2025 08:14:27 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R11" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4ZqLDM0l1Fz3dSx; Sat, 03 May 2025 08:14:27 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1746260067; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=fmNGYG1JaPZ7Ho9BrqCVwJix+8EDNu3PXdr2nxhWCoI=; b=S4Jf5WkOAwnlyAJlnKHPKPs40UrMq52r/PGfqndpmBrx2iGXaqDRsc7f/n/7x51xv0eQ7f v8DYmCq308cN2Q6XXBce40ulHhhPmVQ9qu/pxOv/L9iWUKEA8PZqC8evo5X4UFiBk4AT3T 3pz78faj8vYr697Qk5L9/YZOoJc1WnVhUG2xzJKvPWT8PDj9+eZriek/LmA5UJ9x28TKhW Wq67YzBitm/5qbUhLdLRRRXBLgBW8dS+iIgSEms9zGt60VwTLg6KtKkiHrpxAr7Zwi9CBG VWp6e2Np4cryoryYn6Ag2l0ZyBGK9kwxCbcB5x5Y5Og5aa+alYuURwW79uZ8QA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1746260067; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=fmNGYG1JaPZ7Ho9BrqCVwJix+8EDNu3PXdr2nxhWCoI=; b=xLYngX7+bOMZM4xIW1W46qXsFJNwVapEdK8OczIAtxfIMpYc9UQ1gc9MAvCSevtidc6qH0 YCOJUx3fbsWRUrhJEUMEBBAbfA098KBuLTQavDZtAug6owbnzyAz/Zi/O1G1e9GblG1ehq UBo66DqqqQFChdtokM2izKO6erZnZf3dqoW7pAExiikLsvKic+EyFd//hDnPKJLA/U7Hsa hclZdhSTQehbXVG7EAY7eNWAyFPWFFkgN8YhjRYIbd/ReEygOX3FWIF8htcTWHPFWb9/zg oiyUQR/xu9OTBEKaAKjoeXrAeXkE2mZixUbgvOzHQVNRJJJZ2tpY8G6zva1sRw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1746260067; a=rsa-sha256; cv=none; b=VxK+gJBqRIwW8iTAgOMP/6t6p+JZ5OVFcWT50EvH24BT4ockXy/QfIfeRM6LqEthwKub1g oS6gzDx7UtteKslmrvtguG4zL5dYbUUp/8vaL0kREXW06hAAKrWGHRwjMvQpbZ9JfWGAzB TxCcr30Lcim5pAk8OTSADwMhcG5f8fGfq8kDAG4Up/cXWE4HbL6A2p4tQy+59IakBW6qF8 XsTf4NvbaJtXjLJIMb//y+LxjzUuIYEmKg/g8VaBQBwwFZvs4FmYsBxiUYhVnVQiX7sA/y yPhNQjSiB13L0ZXGbBbCpcQ0aSlZ6TUm+91mDeWX93Jeu3w0so2kA0yZpbkgZg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4ZqLDM008Vzb2T; Sat, 03 May 2025 08:14:26 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 5438EQ9w053327; Sat, 3 May 2025 08:14:26 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 5438EQoi053324; Sat, 3 May 2025 08:14:26 GMT (envelope-from git) Date: Sat, 3 May 2025 08:14:26 GMT Message-Id: <202505030814.5438EQoi053324@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Kristof Provost Subject: git: 9485d2228660 - main - pf: send a challenge ACK for SYN's matching existing states List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kp X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 9485d22286603ef2ac2e2009dd7dfcc6a59e2283 Auto-Submitted: auto-generated The branch main has been updated by kp: URL: https://cgit.FreeBSD.org/src/commit/?id=9485d22286603ef2ac2e2009dd7dfcc6a59e2283 commit 9485d22286603ef2ac2e2009dd7dfcc6a59e2283 Author: Kristof Provost AuthorDate: 2025-05-02 12:24:27 +0000 Commit: Kristof Provost CommitDate: 2025-05-03 08:13:52 +0000 pf: send a challenge ACK for SYN's matching existing states PF should send a challenge ACK as response to SYN, which matches existing state. Extra thanks goes to bluhm@ for careful testing and fixing patch I've sent to tech@ O.K. henning@ bluhm@ Obtained from: OpenBSD, sashan , 6679bb1581 Sponsored by: Rubicon Communications, LLC ("Netgate") --- sys/netpfil/pf/pf.c | 62 ++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 15 deletions(-) diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c index a1301e59533b..8c74b15ef991 100644 --- a/sys/netpfil/pf/pf.c +++ b/sys/netpfil/pf/pf.c @@ -4373,6 +4373,25 @@ pf_icmp_to_bandlim(uint8_t type) } } +static void +pf_send_challenge_ack(struct pf_pdesc *pd, struct pf_kstate *s, + struct pf_state_peer *src, struct pf_state_peer *dst) +{ + /* + * We are sending challenge ACK as a response to SYN packet, which + * matches existing state (modulo TCP window check). Therefore packet + * must be sent on behalf of destination. + * + * We expect sender to remain either silent, or send RST packet + * so both, firewall and remote peer, can purge dead state from + * memory. + */ + pf_send_tcp(s->rule, pd->af, pd->dst, pd->src, + pd->hdr.tcp.th_dport, pd->hdr.tcp.th_sport, dst->seqlo, + src->seqlo, TH_ACK, 0, 0, s->rule->return_ttl, 0, 0, 0, + s->rule->rtableid); +} + static void pf_send_icmp(struct mbuf *m, u_int8_t type, u_int8_t code, sa_family_t af, struct pf_krule *r, int rtableid) @@ -7013,22 +7032,35 @@ pf_test_state(struct pf_kstate **state, struct pf_pdesc *pd, u_short *reason) if ((action = pf_synproxy(pd, *state, reason)) != PF_PASS) return (action); - if ((*state)->src.state >= TCPS_FIN_WAIT_2 && - (*state)->dst.state >= TCPS_FIN_WAIT_2 && - (((tcp_get_flags(th) & (TH_SYN|TH_ACK)) == TH_SYN) || - ((tcp_get_flags(th) & (TH_SYN|TH_ACK|TH_RST)) == TH_ACK && - pf_syncookie_check(pd) && pd->dir == PF_IN))) { - if (V_pf_status.debug >= PF_DEBUG_MISC) { - printf("pf: state reuse "); - pf_print_state(*state); - pf_print_flags(tcp_get_flags(th)); - printf("\n"); + if (((tcp_get_flags(th) & (TH_SYN | TH_ACK)) == TH_SYN) || + ((th->th_flags & (TH_SYN | TH_ACK | TH_RST)) == TH_ACK && + pf_syncookie_check(pd) && pd->dir == PF_IN)) { + if ((*state)->src.state >= TCPS_FIN_WAIT_2 && + (*state)->dst.state >= TCPS_FIN_WAIT_2) { + if (V_pf_status.debug >= PF_DEBUG_MISC) { + printf("pf: state reuse "); + pf_print_state(*state); + pf_print_flags(tcp_get_flags(th)); + printf("\n"); + } + /* XXX make sure it's the same direction ?? */ + pf_set_protostate(*state, PF_PEER_BOTH, TCPS_CLOSED); + pf_remove_state(*state); + *state = NULL; + return (PF_DROP); + } else if ((*state)->src.state >= TCPS_ESTABLISHED && + (*state)->dst.state >= TCPS_ESTABLISHED) { + /* + * SYN matches existing state??? + * Typically happens when sender boots up after + * sudden panic. Certain protocols (NFSv3) are + * always using same port numbers. Challenge + * ACK enables all parties (firewall and peers) + * to get in sync again. + */ + pf_send_challenge_ack(pd, *state, src, dst); + return (PF_DROP); } - /* XXX make sure it's the same direction ?? */ - pf_set_protostate(*state, PF_PEER_BOTH, TCPS_CLOSED); - pf_remove_state(*state); - *state = NULL; - return (PF_DROP); } if ((*state)->state_flags & PFSTATE_SLOPPY) { if (pf_tcp_track_sloppy(*state, pd, reason, src, dst,