From nobody Tue Aug 25 15:59:47 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 4hTstD6lgxz6pbXh for ; Tue, 25 Aug 2026 15:59:48 +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 4hTstD02DCz428S for ; Tue, 25 Aug 2026 15:59:47 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1787673588; 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=KdEiL9H0TyDhFiknhHtFBYNFJWP4tl/C+9SP6Ww/u+w=; b=NXotuY7uiLSFHaOLghnE3KoVYA4QV4RKHjC8MAGKcAxy/UIaXIMohCgbG/6gak6l9V3C9X Oa8dR7WUSBJ3SFcdLhrUTqwZ4QuhEyMT9rsFMJ1HTfoBWS5Z7YKMZLLv7gGuNxwBkGXYQf zOiIBEqwUi0SDYFx/5dgAz4UKM5OIAOJlW3NZzd/EzQ0Bd8ogZ07zwipN8zhEvpfI2ghUZ f+Bn2TUQk5liB8oh2zutbHhX8M091sSk5gHMgAh0j8LmSlVnKBztYgcPjSuvnmUt6GdQwp j6xBfate5WFj0tFZRzBZSKY4VTKjxDL7o0n0SkbGbI0sLgRAHEfergFxqwXa3Q== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1787673588; a=rsa-sha256; cv=none; b=S6oSdH+Fuvk/QMW5qIJwlI6xPoFf6TPHgpvgnqS9lArbNh1z0JWMPstGGaSYFCIw48SQLd kji5166Q1T5kijlCdXBSzhJ/8G5twi7FpstJmurIbK1N54nhTnNjT4PA3+aYmy1atKc59j ZElogMzCcGlXi/R4rHZsFyyItCR5oL6kvWwPqJP6y5mHDntPxz0KN2PpyVi1iVhcSXN82X lwt3FcMpkEOknOWDUkV92AYuncPfSi3EYWdMIfrW7exXVHpE4luPBpk3PfheZ4HJlKHvBS uNjoRzxKMJReeH5OJuHE0jSdbK5g9NvduWxwxfkAjv9tc1xIX917x9rAjQJUMQ== 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=1787673588; 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=KdEiL9H0TyDhFiknhHtFBYNFJWP4tl/C+9SP6Ww/u+w=; b=ocnCtIkKjQ7TW9LO1xOVs+sfKjJ8hKrjgSf80zK502b2nAoMEyjPqZKGUCh+7FUeO2UMwJ p1+fVWlRmmoYvdeELerkFMNetGjG1l4Zj9wZ7jaXpuk/tBvVFip7qK3nSO3B6F5bh13zN8 K2zXAIqwuZoximtisAJ1c1elXqJezMOabKKnoCI9T2ttFMlvECYhKFQTtK/nwCPCwFMjF6 Kwo6WN8sIRHenaUOI0FAtjSP0rkd7FpygC9bB3S5umBD0nJUy/jM8knoAP0hRYfQJaWya2 UsrLf1dhtqWCzci1ZkepHOyfe82Nm1WEyjaNmjvjypE8Zviz88mh04AS78rSMw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hTstC5cZmzy60 for ; Tue, 25 Aug 2026 15:59:47 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 31046 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 25 Aug 2026 15:59:47 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 87bb4aa63ac7 - stable/15 - hwpmc: Fix the execve handler 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: 87bb4aa63ac789dd2821753f04bae5c768f343df Auto-Submitted: auto-generated Date: Tue, 25 Aug 2026 15:59:47 +0000 Message-Id: <6a8dbbf3.31046.3285e9e2@gitrepo.freebsd.org> The branch stable/15 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=87bb4aa63ac789dd2821753f04bae5c768f343df commit 87bb4aa63ac789dd2821753f04bae5c768f343df Author: Mark Johnston AuthorDate: 2026-08-24 14:57:16 +0000 Commit: Mark Johnston CommitDate: 2026-08-25 15:47:12 +0000 hwpmc: Fix the execve handler When a process execve()s, pmc_process_exec() is supposed to evaluate whether the new image is setuid/setgid and if so, whether to detach PMCs. This was handled by pmc_can_attach(), which is effectively an open-coded copy of cr_xids_subset(). Unfortunately, the test of the result of this function was inverted, with the result that we'd detach PMCs only if the predicate said it was okay to do so. It appears the bug has always been there; it seems the intent was to return 0 on "success", i.e., it is okay to attach the PMCs, much like p_candebug(). Commits 1c3c698ba4c4 and 1c40b15971f0 obscured this a bit. I think this check is trying to be too clever. Let's make it simpler: simply do not attach PMCs unless the owner is privileged. This is how, e.g., ktrace works. I do not think it's worth trying to be more sophisticated than this unless we can generalize the policy in a way that's applicable to other subsystems. Also fix a bug at the end of pmc_process_exec(): pmc_detach_one_process() will call pmc_remove_process_descriptor() for us. Approved by: so Security: FreeBSD-SA-26:56.hwpmc Security: CVE-2026-58089 Reported by: netchild Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D59102 --- sys/dev/hwpmc/hwpmc_mod.c | 72 ++++++++--------------------------------------- sys/kern/kern_exec.c | 2 +- 2 files changed, 13 insertions(+), 61 deletions(-) diff --git a/sys/dev/hwpmc/hwpmc_mod.c b/sys/dev/hwpmc/hwpmc_mod.c index 70c974857f5c..98ef14885c10 100644 --- a/sys/dev/hwpmc/hwpmc_mod.c +++ b/sys/dev/hwpmc/hwpmc_mod.c @@ -210,7 +210,6 @@ static int pmc_attach_one_process(struct proc *p, struct pmc *pm); static bool pmc_can_allocate_row(int ri, enum pmc_mode mode); static bool pmc_can_allocate_rowindex(struct proc *p, unsigned int ri, int cpu); -static bool pmc_can_attach(struct pmc *pm, struct proc *p); static void pmc_capture_user_callchain(int cpu, int soft, struct trapframe *tf); static void pmc_cleanup(void); @@ -1025,60 +1024,6 @@ pmc_unlink_target_process(struct pmc *pm, struct pmc_process *pp) } } -/* - * Check if PMC 'pm' may be attached to target process 't'. - */ - -static bool -pmc_can_attach(struct pmc *pm, struct proc *t) -{ - struct proc *o; /* pmc owner */ - struct ucred *oc, *tc; /* owner, target credentials */ - bool decline_attach; - - /* - * A PMC's owner can always attach that PMC to itself. - */ - - if ((o = pm->pm_owner->po_owner) == t) - return (true); - - PROC_LOCK(o); - oc = o->p_ucred; - crhold(oc); - PROC_UNLOCK(o); - - PROC_LOCK(t); - tc = t->p_ucred; - crhold(tc); - PROC_UNLOCK(t); - - /* - * The effective uid of the PMC owner should match at least one - * of the {effective,real,saved} uids of the target process. - */ - - decline_attach = oc->cr_uid != tc->cr_uid && - oc->cr_uid != tc->cr_svuid && - oc->cr_uid != tc->cr_ruid; - - /* - * Every one of the target's group ids, must be in the owner's - * group list. - */ - for (int i = 0; !decline_attach && i < tc->cr_ngroups; i++) - decline_attach = !groupmember(tc->cr_groups[i], oc); - if (!decline_attach) - decline_attach = !groupmember(tc->cr_gid, oc) || - !groupmember(tc->cr_rgid, oc) || - !groupmember(tc->cr_svgid, oc); - - crfree(tc); - crfree(oc); - - return (!decline_attach); -} - /* * Attach a process to a PMC. */ @@ -1442,10 +1387,19 @@ pmc_process_exec(struct thread *td, struct pmckern_procexec *pk) */ for (ri = 0; ri < md->pmd_npmc; ri++) { if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) { - if (pmc_can_attach(pm, td->td_proc)) { + struct proc *owner; + struct ucred *cred; + + owner = pm->pm_owner->po_owner; + PROC_LOCK(owner); + cred = crhold(owner->p_ucred); + PROC_UNLOCK(owner); + + if (priv_check_cred(cred, PRIV_DEBUG_DIFFCRED) != 0) pmc_detach_one_process(td->td_proc, pm, PMC_FLAG_NONE); - } + + crfree(cred); } } @@ -1458,10 +1412,8 @@ pmc_process_exec(struct thread *td, struct pmckern_procexec *pk) * PMCs, we can remove the process entry and free * up space. */ - if (pp->pp_refcnt == 0) { - pmc_remove_process_descriptor(pp); + if (pp->pp_refcnt == 0) pmc_destroy_process_descriptor(pp); - } } /* diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c index 5f7adae8df03..a109871d7673 100644 --- a/sys/kern/kern_exec.c +++ b/sys/kern/kern_exec.c @@ -1037,7 +1037,7 @@ interpret: */ if (PMC_SYSTEM_SAMPLING_ACTIVE() || PMC_PROC_IS_USING_PMCS(p)) { VOP_UNLOCK(imgp->vp); - pe.pm_credentialschanged = credential_changing; + pe.pm_credentialschanged = imgp->credential_setid; pe.pm_baseaddr = imgp->reloc_base; pe.pm_dynaddr = imgp->et_dyn_addr;