From nobody Tue Apr 21 15:42:31 2026 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 4g0RSR5C6Lz6WtQw for ; Tue, 21 Apr 2026 15:42:31 +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 4g0RSR4f4Zz3Lhs for ; Tue, 21 Apr 2026 15:42:31 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1776786151; 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=zJUNV1lcp08qA+fuTgn3eovYGbxGVgCNA1/fyeAuBfo=; b=ceowSWrFeciUczmVxTO+DpZTV+s2Uv/BlA4ErAEzlrBw4mGOHPg4nxI0bUySIMILe+CYjD mMDnBLpSnREgnydR8COYHuaAhWqz84miL7tZGTVyoO7ljjr+R+xLdubPdTVDhvWNgh/Za+ SVqpcGeamvQA1SaPj66LQs44EkZzWqtPXz1GJ7MBl4xMhQBFxhs/m4eYlrC2385JFAH1dc zhQv68C6ImhXU1FSEgaDbVfR9h41+A6AzjBbM75LXTNv7CttN8wlnlX6dw5YmPUQnmfjTD zDGsqLTtX5I7RLebzFbsLpHf4S9XnH9zSfX33KIkoWPGfU+XpaLzoKJ2rDyyhA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1776786151; a=rsa-sha256; cv=none; b=AUgiXCFQ+v5lFZJeXeu4Ig7vtlUxcSY59g0myQCmSbcDlUzCdmeAbVLksklMX3qrBzoSDT 3w8RjdYpBGj/+52nRD8UuEATvtg+k0XaY0DtOnlC/6S2/9mTmFusBtlrOeuslFhY+VrNOX BJz8DlbepkHpbf6EQaJq+P2TslKvcn+3UcrLKH+6IPzFMrThySKlzKUn0NSimdfMWSzvf9 JIVhiXKxZjvzikSP9JeWbTi23t6hseqydztfr6/ph10WpCcxF1pz0k7qVIiszi3xod5sUX WvOWTK4uuzxpLGwZRowB1va4UNIiAKdUluuseNLQlNj66c8+7IorDbg8JMuqBg== 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=1776786151; 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=zJUNV1lcp08qA+fuTgn3eovYGbxGVgCNA1/fyeAuBfo=; b=xM9m/cSbb5F8mKrAoZC4Wt/XZm1FT2K9Zqntp9n7ppE00L3uEkFf+NaY0hVLbvbBmmLU/o N2dj1N3QWa5cKV7O5CsGR6xXF2uj12RS96vBBOWTlfqBZ0tY8jY/cEvxBuaYlPm197OP6B XqcCMMR5FcWuAVtkQrYsjiAStVyG4NL9m79v/ur6AWsj0G3wO/VaMIBHCkgqWN1w6cbH16 NKT8hrQMJPiek6LIW719aCimDLqDYmrC4ho5pUsBKFiqQI2W3MGIL3/Sjcn3BGWRNEhDI/ JK9SLw5+GEt79VpULYyvhIREzaYBTOj3uRcpKNm1UXvh8U07JBeDtr0Uhu0AJw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4g0RSR4Cg0zqyP for ; Tue, 21 Apr 2026 15:42:31 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 33d46 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 21 Apr 2026 15:42:31 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: 093903a8d4c0 - main - tty: Avoid leaving dangling pointers in tty_drop_ctty() 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: markj X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 093903a8d4c05d1adff79895a52a3e3009ff07a7 Auto-Submitted: auto-generated Date: Tue, 21 Apr 2026 15:42:31 +0000 Message-Id: <69e79ae7.33d46.70134080@gitrepo.freebsd.org> The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=093903a8d4c05d1adff79895a52a3e3009ff07a7 commit 093903a8d4c05d1adff79895a52a3e3009ff07a7 Author: Mark Johnston AuthorDate: 2026-03-23 15:22:48 +0000 Commit: Mark Johnston CommitDate: 2026-04-21 15:41:34 +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 9297fc81df5e..3d20d225087c 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)); +}