From nobody Tue Apr 21 15:44:27 2026 X-Original-To: dev-commits-src-all@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 4g0RVh0DLjz6Wtmj for ; Tue, 21 Apr 2026 15:44:28 +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 "R13" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4g0RVg4f6Wz3Pnj for ; Tue, 21 Apr 2026 15:44:27 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776786267; 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=n2W1sMKPkBnmEoOlYGE7L+GGisJ0iVYUwqpzD0FJwmo=; b=HP00KuShizORy4uPno8cUL9uYgI2ExcyA3eNw658mbnnzREI7zTb47+Zfjv34Nsx9yACC0 1B6MyCosbpkhhWPEv6AZv1y5rWJEn1FLfknsfNqkQVY04+oTb/Kf00jVwM44TIsucUUw5W lQECuNZDhSik0sJN1iJVmxAi5sqDQLxLgiogobV7jUmx2Nf7tSxqK7qsozQosdfqmp0Y/s x/snVwWCO41G3F123CBHaoW2z/kSoTwZM9a4znUq0N8cyveKwKSeZIf126xWp7OEb/2CiV Np538RDG7GgEi+hSdMYjYTM8icwoFRJbhyMYyj9+o0hZ6OXa7mmGjAgYaunNdA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1776786267; a=rsa-sha256; cv=none; b=ZIhqJwUc75PLxeBcXrWeaWciAPBQvmE+jS3GZqmrQvnJyF/6SEfEyenAIVWjRR4nT1lJgE f0KU9YoioNDybse+IMfhqRr8XQf32wza7LocrQ+Xa/f0wR/cHlS3QPF8j49/U9MCwNp7fC N9t+I/Cp/UsMpIPVGsiSCI6zwmh5eUmaaW+BoFeHBMxjFD8k+vW805WqHe+4to0E7C55Ls g+UIbnk5rssaoQ8nXF71d6nBZAwdD/lNWlH6EZrN1E9vJCIgFgYo9Kr0Qt31PEfmelesXu QIKgrqZZ28HjpJ87JSEv7xt6maEMEdhg/TxZ4+NVl+xYuqf8+TyxfvnUbqRFew== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776786267; 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=n2W1sMKPkBnmEoOlYGE7L+GGisJ0iVYUwqpzD0FJwmo=; b=an+b7UuoRKjQ3caCxX1BjIVZjhExN3ujqfdZNoLf0QaZ0yjLeurtGzzVgKGtI0CF6Iy+N5 yLL8ayT/Uw3iChjGPlTewiLfxYVXY4DQQT+6YKbUruxMwazxfdmYATXvL2gS55FHACw/UL 6xXMTj/wXsOqSUDVKzz/HN4TftylUtCj0W2ZPNYsCSjFdTbosKrsX/bCxES5FLjUTcO4YK MN4KnIdrv3jPPpT/zN0kZLTY1M1R5QyPoajNJW8IQceV8wWLmPeMpVrG1X0R4uVxAqK0Os BCVejb7AW+2xSh5jtzWFs0QmFEuUTaTiSXaiJmMLq/cL/ZpmJ9p4F+XJTZmjEg== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4g0RVg3yKHzq7w for ; Tue, 21 Apr 2026 15:44:27 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 344d9 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 21 Apr 2026 15:44:27 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: fdee312d0c97 - releng/15.0 - tty: Avoid leaving dangling pointers in tty_drop_ctty() List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/releng/15.0 X-Git-Reftype: branch X-Git-Commit: fdee312d0c97cf6d907eec0b96efd51bfc9a7567 Auto-Submitted: auto-generated Date: Tue, 21 Apr 2026 15:44:27 +0000 Message-Id: <69e79b5b.344d9.b6cf70e@gitrepo.freebsd.org> The branch releng/15.0 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=fdee312d0c97cf6d907eec0b96efd51bfc9a7567 commit fdee312d0c97cf6d907eec0b96efd51bfc9a7567 Author: Mark Johnston AuthorDate: 2026-03-23 15:22:48 +0000 Commit: Mark Johnston CommitDate: 2026-04-20 13:19:13 +0000 tty: Avoid leaving dangling pointers in tty_drop_ctty() The TIOCNOTTY handler detaches the calling process from its controlling terminal. It clears the link from the session to the tty, but not the pointers from the tty to the session and process group. This means that sess_release() doesn't call tty_rel_sess(), and that pgdelete() doesn't call tty_rel_pgrp(), so the pointers are left dangling. Fix this by clearing pointers in tty_drop_ctty(). Add a standalone regression test. Approved by: so Security: FreeBSD-SA-26:10.tty Security: CVE-2026-5398 Reported by: Nicholas Carlini Reviewed by: kib, kevans Fixes: 1b50b999f9b5 ("tty: implement TIOCNOTTY") Differential Revision: https://reviews.freebsd.org/D56046 --- sys/kern/tty.c | 4 +++ tests/sys/kern/tty/Makefile | 1 + tests/sys/kern/tty/tiocnotty.c | 82 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 87 insertions(+) diff --git a/sys/kern/tty.c b/sys/kern/tty.c index c8e2c561b7cf..356a69682997 100644 --- a/sys/kern/tty.c +++ b/sys/kern/tty.c @@ -1261,6 +1261,10 @@ tty_drop_ctty(struct tty *tp, struct proc *p) session->s_ttydp = NULL; SESS_UNLOCK(session); + if (tp->t_session == session) { + tp->t_session = NULL; + tp->t_pgrp = NULL; + } tp->t_sessioncnt--; p->p_flag &= ~P_CONTROLT; PROC_UNLOCK(p); diff --git a/tests/sys/kern/tty/Makefile b/tests/sys/kern/tty/Makefile index 8628ab79875f..d134b3337a21 100644 --- a/tests/sys/kern/tty/Makefile +++ b/tests/sys/kern/tty/Makefile @@ -5,6 +5,7 @@ PLAIN_TESTS_PORCH+= test_canon PLAIN_TESTS_PORCH+= test_canon_fullbuf PLAIN_TESTS_PORCH+= test_ncanon PLAIN_TESTS_PORCH+= test_recanon +PLAIN_TESTS_C+= tiocnotty ATF_TESTS_C+= test_sti PROGS+= fionread diff --git a/tests/sys/kern/tty/tiocnotty.c b/tests/sys/kern/tty/tiocnotty.c new file mode 100644 index 000000000000..2581f976b2ef --- /dev/null +++ b/tests/sys/kern/tty/tiocnotty.c @@ -0,0 +1,82 @@ +/* + * Copyright (c) 2026 Mark Johnston + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +/* + * A regression test that exercises a bug where TIOCNOTTY would leave some + * dangling pointers behind in the controlling terminal structure. + */ + +#include +#include + +#include +#include +#include +#include +#include + +int +main(void) +{ + int master, slave, status; + pid_t child; + + master = posix_openpt(O_RDWR | O_NOCTTY); + if (master < 0) + err(1, "posix_openpt"); + if (grantpt(master) < 0) + err(1, "grantpt"); + if (unlockpt(master) < 0) + err(1, "unlockpt"); + + child = fork(); + if (child < 0) + err(1, "fork"); + if (child == 0) { + if (setsid() < 0) + err(1, "setsid"); + slave = open(ptsname(master), O_RDWR | O_NOCTTY); + if (slave < 0) + err(2, "open"); + if (ioctl(slave, TIOCSCTTY, 0) < 0) + err(3, "ioctl(TIOCSCTTY)"); + /* Detach ourselves from the controlling terminal. */ + if (ioctl(slave, TIOCNOTTY, 0) < 0) + err(4, "ioctl(TIOCNOTTY)"); + _exit(0); + } + + if (waitpid(child, &status, 0) < 0) + err(1, "waitpid"); + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) + errx(1, "child exited with status %d", WEXITSTATUS(status)); + + child = fork(); + if (child < 0) + err(1, "fork"); + if (child == 0) { + struct winsize winsz; + + if (setsid() < 0) + err(1, "setsid"); + slave = open(ptsname(master), O_RDWR | O_NOCTTY); + if (slave < 0) + err(2, "open"); + /* Dereferences dangling t_pgrp pointer in the terminal. */ + memset(&winsz, 0xff, sizeof(winsz)); + if (ioctl(slave, TIOCSWINSZ, &winsz) < 0) + err(3, "ioctl(TIOCSWINSZ)"); + /* Dereferences dangling t_session pointer in the terminal. */ + if (ioctl(slave, TIOCSCTTY, 0) < 0) + err(4, "ioctl(TIOCSCTTY)"); + _exit(0); + } + + if (waitpid(child, &status, 0) < 0) + err(1, "waitpid"); + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) + errx(1, "child exited with status %d", WEXITSTATUS(status)); +}