From nobody Tue Sep 29 15:56:18 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 4hvN832dnqz6tlC3 for ; Tue, 29 Sep 2026 15:56:19 +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 "YR2" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4hvN826dpRz4VHR for ; Tue, 29 Sep 2026 15:56:18 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1790697378; 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=fJywF9hJuI6W2czcxvX84Ycb2oCS0JGEICBS/LEhrHU=; b=ND5/OrOD4AFVz5rNOgcG0Q1Z48QwlrzUYP/fW6EyfbKOky0csIwy3elkWS5YkZLUqKEGqi bdms2E+DKaunKlxIqIocimWPhqLm4kuQO19Cbb3a0gm01PJuQi/cP2h1iZFzUZP80a5Nhx GiJYBO0N7M5/d8kkqCk0AjQoRtCNFyhK0GWgBuabM85ZL+aOqnLKBPtgDNBwe2JVM5MxM6 QNiAiZSMhFDpF+pfWrijVwBSBEZmCINhpy96J+Frtu/mtwocdCwV9Hsiq4hY/fGsp9kvq1 SQXXUwu1vgv6eUghi3I25nkEctIf93+8v7t5YqbGdUJKeGW11rARCP44PiWmPQ== ARC-Seal: i=1; a=rsa-sha256; d=freebsd.org; s=dkim; cv=none; t=1790697378; b=QBf8icVgn6h8dmM+kksozCBUEBZvP2BmcTUE9R7umnYnDWJGzWlWTgD7QOAqgo71yI2jOo /QhidoEGpOzEWcftBRO4zsydGjcaNgLtGyFNzVN0bAUFbFtaR4Gi7PNZ47jQ6vDVK8LiMS NUcLoXSMuk4j0oQxdpYhon+9GY+QfDtOTu/pRvs/EFO2SIeeEXJodz5KVK7L07m8PdiuJH uvSY3p2wJ30pfOQnbuJwOXSwKzcuK/6QQMDjBGgXNeKdYF2SRfmyOuYFC3qG8rK01oLtz0 WP7reBpe5gsK5XDgNavnlZHxp91e3wol82fCieZAuXsCjmihcQBn7XtJrfR5/w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1790697378; 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=fJywF9hJuI6W2czcxvX84Ycb2oCS0JGEICBS/LEhrHU=; b=Q5xPm8Fa9SSQhBobC0P+aF0y/2yof4bOxewAIFkEjphxeOYGB860IN9PfwxqVJx7JeRs/B u0lOO26sj+cK3nEXrtjHoXLM74/a/bdsVSiggtalYtSFaCDNDIeq0elehEu8gRBoE2LAnY 2VNuuU9X7Kr3873tvM6Mv2f5w9Vxw7Y5lhahVCFdKfNnKLKIAISfShWGZUWK8yPsuzuG75 PtWnf8TQP9njVc+XfxNfweIggwg/v7KLLxkJUlYdd48B5Qxoh2IHK+ubciW2wlNDBSdeBA zr/4QHouzJFW96x9XyGggLmr7emZiJX87VoMvwe2lAgvMEEWECrzOOoSredN1A== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hvN825KDhz1JRF for ; Tue, 29 Sep 2026 15:56:18 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 261de by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 29 Sep 2026 15:56:18 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 0ee32bf5318d - stable/15 - kqueue: Fix handling of marker knotes during fork 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 List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list 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: 0ee32bf5318dd3221111d76df079ef99f4346178 Auto-Submitted: auto-generated Date: Tue, 29 Sep 2026 15:56:18 +0000 Message-Id: <6abbdfa2.261de.465e67ef@gitrepo.freebsd.org> The branch stable/15 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=0ee32bf5318dd3221111d76df079ef99f4346178 commit 0ee32bf5318dd3221111d76df079ef99f4346178 Author: Mark Johnston AuthorDate: 2026-09-28 13:40:45 +0000 Commit: Mark Johnston CommitDate: 2026-09-29 15:56:01 +0000 kqueue: Fix handling of marker knotes during fork Commit d8bdcb08d0eb fixed a problem in kqueue_fork_copy_knote() where we did not skip over marker knotes when copying. However, that fix was not sufficient: we bump the influx counter and check for a marker after dropping the kqueue lock. So, if multiple threads in a process are forking concurrently, kqueue_fork_copy_list() may mark a marker as in-flux and drop the lock; if the marker owner then frees the marker, the first thread will decrement the in-flux counter of a freed knotes. This use-after-free can be exploited, at least prior to commit d8bdcb08d0eb, which makes exploitation more challenging. Approved by: so Security: FreeBSD-SA-26:65.kqueue Security: CVE-2026-58099 Reported by: Reo Shiseki Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D59522 --- sys/kern/kern_event.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c index 456eddfaea9f..32e2e6e69d7e 100644 --- a/sys/kern/kern_event.c +++ b/sys/kern/kern_event.c @@ -3096,9 +3096,9 @@ kqueue_fork_copy_knote(struct kqueue *kq, struct kqueue *kq1, struct knote *kn, ("%s: knote %p not in flux", __func__, kn)); KASSERT((kn->kn_status & KN_DETACHED) == 0, ("%s: knote %p not detached", __func__, kn)); + KASSERT((kn->kn_status & KN_MARKER) == 0, + ("%s: knote %p not detached", __func__, kn)); - if ((kn->kn_status & KN_MARKER) != 0) - return; if ((kn->kn_status & KN_KQUEUE) != 0) { /* * We cannot hold references to a kqueue outside of the process @@ -3164,7 +3164,7 @@ kqueue_fork_copy_list(struct klist *knlist, struct knote *marker, kn = SLIST_FIRST(knlist); while (kn != NULL) { MPASS(kn->kn_kq == kq); - if ((kn->kn_status & KN_DETACHED) != 0 || + if ((kn->kn_status & (KN_DETACHED | KN_MARKER)) != 0 || (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0)) { kn = SLIST_NEXT(kn, kn_link); continue;