From nobody Tue Apr 21 15:43:02 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 4g0RT26pbWz6WtfY for ; Tue, 21 Apr 2026 15:43:02 +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 4g0RT267pzz3MDB for ; Tue, 21 Apr 2026 15:43:02 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776786182; 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=uvD+/NNVHHt3iwEcYJBthz2Ufe9GomZgvC9QrMY3Ck8=; b=NwzBKVtXflmdYc79IYVrsOgdl2C6JnZ0B9Fb0Zy7NARCHNHLYodlcVuf9TKIY/aTxoZuFV s1pHJM264cVQ8FOjF6TLerkAjMnYfFFWv4MsYH5hKBfXGzd9pFdfTx43BO5SqowgkFG/gs Zp/dJFH7zB+3pZ5BE+LoZEaS01guKrSxs4b50EuTjlKbinj2LFKHB6eFvQi+mxnWs8vFZ1 L9aigj7Tmqb+ilAMgGDo2nn4dLSbdRmNLCT1kyL+m+sq8BN5w693ucaZBRlzyR/TeSICUw whxSU4KKnPDDCExXPrdd/OF/34Ssr8EAV888xoAx9Re28gf/8lnTO60axMAgug== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1776786182; a=rsa-sha256; cv=none; b=uI/I0iHPWJ6A3aRM3MJXPQMRge6lsCCXKBhbSuf+bSqMCZF/mpEEoBJukgo7CZYWXYyNEo CThp7VG0I7IPtNHQWhrZHQzQ80IEh9HAditl/60OJpWTFg5lPl0YiGUo6nE6MGx1Uv9mkn x7dBnctuQ0FeUkkkX0i045SR8gvylOBKlOEYam9pE2X19MXq2NKO5UFtlaXcCp0p9BbWo2 uEvj2kSlPQ+cvQdUpYu+ZtosyBUxMxYyOs/wjoj38bqRWz5OiIda+4ny3ZdRXkvtr1/uRT Yfs4WddtDPDjN0ikHHaMplixej1IUa8Ddj4lhkvDyKFT2mtQR8opUnujpPRi6A== 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=1776786182; 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=uvD+/NNVHHt3iwEcYJBthz2Ufe9GomZgvC9QrMY3Ck8=; b=kk0Wr49gznkFZNO1ZjwVo77TYYQ/u6ZzR7oo4yQWF+lnMoNpDBeyyMPwkXpSJ0FwVTai3F kYSY7mntu/e+0X8V9t5I6QHsKGmhEIZFrDg1LRNuwKJK/AdqYNjnaNzbU9ECTtIpGGPQ7o QxQTX+6fg/jQr8D/9YKKapvI18io76h9AHbFQ82Rl2bN/9BL2zCJYssqQooxveLkv4wNhh NGO1j5L9ATwMOXUR/1VqOMCbg4eSqiONpre4COBsh/U/5yhOSfPC7imk3xZGlOs0iGrZSG V06+VMcdIUGjvBLCbb7uLL4/coJQbWU92WRw9+xL8elsAwhwan4Vz4fEUyPg7Q== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4g0RT25SmpzqQ2 for ; Tue, 21 Apr 2026 15:43:02 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 36017 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 21 Apr 2026 15:43:02 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 0c6b1e0864b8 - stable/15 - 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/stable/15 X-Git-Reftype: branch X-Git-Commit: 0c6b1e0864b8f2055740b611ab21c73910a73614 Auto-Submitted: auto-generated Date: Tue, 21 Apr 2026 15:43:02 +0000 Message-Id: <69e79b06.36017.319febfc@gitrepo.freebsd.org> The branch stable/15 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=0c6b1e0864b8f2055740b611ab21c73910a73614 commit 0c6b1e0864b8f2055740b611ab21c73910a73614 Author: Mark Johnston AuthorDate: 2026-03-23 15:22:48 +0000 Commit: Mark Johnston CommitDate: 2026-04-21 15:42:40 +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 067471eb949a..afba05ec27b4 100644 --- a/sys/kern/tty.c +++ b/sys/kern/tty.c @@ -1263,6 +1263,10 @@ 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)); +}