From nobody Tue Aug 25 16:01:03 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 4hTsvh4TjTz6pbm0 for ; Tue, 25 Aug 2026 16:01:04 +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 4hTsvh0bthz43wh for ; Tue, 25 Aug 2026 16:01:04 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1787673664; 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=jGdwxJ9s9RBv8H9EMXFyBxIRMvAFlMxKNtTf9+o9new=; b=jIVcHoImV7xnon6WBQmqOvHrf6DRTPkL/kJFRST2b3+SpCnv/b8oYUzz0iaqWxGZyaGQxX LXlp1wUp5Dh+HnUXTnS7HlotAyXcxsrpU5kEiVKPbF46XtdhQGiZn67uZbcEW7lBrkhPE4 RsBkuKUTMlYbAw44BGHh8VdnlaoKelzb2KRA4st8Cp8ANJq6OhuwVp8cPZAl/9NAMGCZvY QtstqshO6NMwTBfkFATS4RzhCqHgikdFL44jUL89U/HhpIPRblsorMfjRJ5KstcKgYoKfe ksN32evfIfCmMZr+XSbO7WMHQBxuN891BIIsbFNlfU2oiyxKSpqRtlwE8iIvww== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1787673664; a=rsa-sha256; cv=none; b=dK2zj3qQNnnm2bcsYk+5ZwXOZpy18trcCvOwBSoolU8NR4XM0NUvE6B+eWke1bG7OqFBcs RxCt/Psdn2iGeSbrhqKJyEl2IIsV01tMyQK5+3nZ7QimFulnoCAeIkT3O63EPeBJXx8o0/ BBPWze3qPACAWBCSisL1fBoURMuYtqH/yIHbvG/tdWQHLIAKQzv3BeEbxd14hbusJSCPcs DbN5A9eAadk1B3X+D0jVTC20eRLn7bjKzF+hxatIXA0JaFwtbmlOUbkoQaIv2HbvSxgfIt BjQTLXpy8u7fsvzRQUo0z633wXZ7LP4moUkQfV5xmsE3GFQaQ78KX+jJDa206Q== 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=1787673664; 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=jGdwxJ9s9RBv8H9EMXFyBxIRMvAFlMxKNtTf9+o9new=; b=mPJAV2BW6mhT9CTdrAKoUbtaCUCj9gGinRQhCRoZgwZeYsukOEwziYko55F07UvaMOO2Al bOurHfw3rR93iRFNSwKWJsrDAbbUl3Uf7ULs7C46dIjkFWOV2barJ+WBNh5OATaFi/cW9w MP9wQQ6Tl6lNdobsqN/wRsusBYmOb+mFh4MPw3BZi2qxCZ3lfM8h3qvuNVg1Yy0A1v7hbz BZzl4A5W3QQfk39OaQ9pZks1v3ynw+5SBDUCg4Re4a16WTyLBTpPfahgjhr3mIPwABvx2m RXV8q/9qHbkDCuZaTVElr47UMnPfRb8IJCQJ5SDK+slAiicbkgEdyZEbH8BQVw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hTsvg6lwnzy8S for ; Tue, 25 Aug 2026 16:01:03 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 334be by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 25 Aug 2026 16:01:03 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 00036dad647f - releng/15.0 - cred: Fix group_is_primary() 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/releng/15.0 X-Git-Reftype: branch X-Git-Commit: 00036dad647ff171b8c1847e92ac74bb511ed9d9 Auto-Submitted: auto-generated Date: Tue, 25 Aug 2026 16:01:03 +0000 Message-Id: <6a8dbc3f.334be.5b449ae@gitrepo.freebsd.org> The branch releng/15.0 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=00036dad647ff171b8c1847e92ac74bb511ed9d9 commit 00036dad647ff171b8c1847e92ac74bb511ed9d9 Author: Mark Johnston AuthorDate: 2026-08-24 18:13:29 +0000 Commit: Mark Johnston CommitDate: 2026-08-24 19:29:47 +0000 cred: Fix group_is_primary() This helper wasn't updated in commit be1f7435ef21, so in reality it was testing whether "gid" is the first supplemental group. If a user doesn't belong to a supplementary group, then it's testing an uninitialized slot; since ucreds are allocated with M_ZERO, this typically means that we're testing gid == 0. group_is_primary() has exactly one use, in mac_do. There, it's used to determine whether to keep the caller's current primary groups. This means that a rule such as gid=0>uid=0 will permit any credential with no supplementary groups. I believe this is mostly exploitable by daemons which have explicitly dropped privileges and called setgroups(0, NULL); logged in users will have a non-empty supplementary group list by virtue of having gone through initgroups(3). Fix group_is_primary(), and add a regression test. Approved by: so Security: FreeBSD-SA-26:59.mac_do Security: CVE-2026-58092 Reported by: Hazley Samsudin of GovTech CSG Fixes: be1f7435ef21 ("kern: start tracking cr_gid outside of cr_groups[]") Reviewed by: olce, kevans Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D59051 --- sys/sys/ucred.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/sys/ucred.h b/sys/sys/ucred.h index 254f58841993..0edd1549b5f6 100644 --- a/sys/sys/ucred.h +++ b/sys/sys/ucred.h @@ -258,7 +258,7 @@ bool cr_xids_subset(struct ucred *active_cred, struct ucred *obj_cred); static inline bool group_is_primary(const gid_t gid, const struct ucred *const cred) { - return (gid == cred->cr_groups[0] || gid == cred->cr_rgid || + return (gid == cred->cr_gid || gid == cred->cr_rgid || gid == cred->cr_svgid); } bool group_is_supplementary(const gid_t gid, const struct ucred *const cred);