From nobody Tue Apr 21 15:43:13 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 4g0RTF34Psz6Wtth for ; Tue, 21 Apr 2026 15:43:13 +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 4g0RTF1Nt2z3Mbl for ; Tue, 21 Apr 2026 15:43:13 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776786193; 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=HH4xZ6t22941TciSU8Mw9snLl7jS2kidscbKwX3yg8g=; b=qI8qJTMa7GYGuwknVhvZAfD+IzE1v381eBy0Z196pqD4zF7LMZO98/M5xv+gZKlvRaATwJ Bju5uiI+zoaXbBaElHsr3Hg747XNMt3dNMJP0Oozt4+5Twgobl/crecpfpBjaULixGLtRK J5vXrmC/khKjAhvxfPmxmSIZtWW+UbRtSun8czydgT4ngGQGIg+HZGhPyH4rchkxxj1mcC zuEooesWGgIIPtCoJXVHYIhYgR0kZc2R0IPfVCKM9KA8TqrnukrtOpn6WjgBSTTO593Nuw nlq3otBBbQcPbHiQ/2xkRPGI4tU8Yl2y0yGJDpsucVdZ2L26FxJnFSjTVopbhA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1776786193; a=rsa-sha256; cv=none; b=qeu0vIdcirqOFcSDoc0Xi0YqSTqClWrkfo6piCNt47k6Wk8xck2kMfIr8+mOkDQ0cHDbOd M+RnKSqpAjQbgfuLSZ0W/kmaSNk6CaTUX9DUE68knyooKk2DAelbF/KTSIqDAAKaaWQORe ZcaDPu2W9xahKKihzW+dfUlzFRm2URZo1OI5pQ7dsqTCv93UmkMvMIbeMOZ09n26B6fcbo Zg5GmNZD0d4IM6xrWkZMCHHn/ZtbdD7PuuJHVIxVX64dytgpTyQAVZIUtszMEMe1d0k0Y5 H+DCFdgjXVFiJlsYpuWjFI8DsZzlI2ycTAnzn0+CRaddXLgXgOV0aGCw3xXKzQ== 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=1776786193; 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=HH4xZ6t22941TciSU8Mw9snLl7jS2kidscbKwX3yg8g=; b=cDp7G7cpd5gBPyx6V8jElm+2ItdU4s0fx+NCeo17XRhWbBDvNnJn2iRIm7R1XEMbjb1xpZ 9FV/FvLdci/VRJ/ySSOIRCpsmG/4/TxC9tZ4UzBGGmAJb5hwW6G1m9DgBOM5uXmMRGpGa9 zXvE3VVMBhRofN+Jt+d8xJFXEalyJQ55s3kTH7dGOFiVNsSsNLi+2hu7rgE+StCAo+1c6z rfUhcH/AM0SHBRcWqliVTj3zVIoRIJCE8qjjyVxemJ+Tr11Kw6xVJmfnDE9KMzJTUHiXy2 rGvsmsLRUPSh8XV7WVWRPrrTDwEZoN+mfh/TNGRLABY3o8cdx2spV56o26+Cmg== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4g0RTF0MhYzqc6 for ; Tue, 21 Apr 2026 15:43:13 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 360c4 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 21 Apr 2026 15:43:13 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: f46210a7ab32 - stable/14 - 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/14 X-Git-Reftype: branch X-Git-Commit: f46210a7ab3227e71cd1fee16d2ede88b648a2df Auto-Submitted: auto-generated Date: Tue, 21 Apr 2026 15:43:13 +0000 Message-Id: <69e79b11.360c4.1e14808d@gitrepo.freebsd.org> The branch stable/14 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=f46210a7ab3227e71cd1fee16d2ede88b648a2df commit f46210a7ab3227e71cd1fee16d2ede88b648a2df Author: Mark Johnston AuthorDate: 2026-03-23 15:22:48 +0000 Commit: Mark Johnston CommitDate: 2026-04-21 15:43:09 +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 47f9f25cec37..508fa10fdd62 100644 --- a/sys/kern/tty.c +++ b/sys/kern/tty.c @@ -1262,6 +1262,10 @@ 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)); +}