From nobody Tue Aug 25 16:00:57 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 4hTsvY6cjKz6pbTG for ; Tue, 25 Aug 2026 16:00:57 +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 4hTsvY3PxDz43pr for ; Tue, 25 Aug 2026 16:00:57 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1787673657; 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=xy4iQ7x9cgzqh6peUyF53fHErGdqyjGB92zah2yYXi8=; b=n8+ygFeJwXoVOdxNBb/mmHNKDH4YeAEQHkoPmAfSxdbpqlwM+xvZGf0n11Msdrho4IZx6k fWGTmulEq1783H4L3FeKkHNQBLWuw1+MzzfjO26IuLPsO8LEXTxldPN0lAclpYZYYz3JrD T304801RPaARteHR0bVhWccS9Kxm2j7COgibJ3+kpQtkKQOOFLquvK/xeIYKBaDuEIPe7B KMF+xWGKy1xNRG1yB4N09qWmRgClajAB6mUf1V7wKTBJaxaPI3Ba58L4YNWeGqIEA7ShPR gcGc0WwXxQenOmBUO5hqIVK9uetqikOtipUywRJyEg342jgyESb3VXwbEO5glw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1787673657; a=rsa-sha256; cv=none; b=KAxk2aqi1L+A3uAOmu/FrZnB6e4/QhbPnYfg1gqVQpdc4dqbb48oZfbVLLCkIPWubPYKgL Ty2fWQiSNsOe4Sp6Uj9qkgUMgh36Lv8muZebox0FFwe6y3vl89lvdv1ehmkyDPGR0pJPw7 4XTL4mlB+e3MD5e0WGZGgDw+L0BA8o1SJq2ATR1ddoI38Bc1zByMHSUIvDXzCpUGu0BQ8P M48syI9xAkjOzWhoEZ+M+iuFu+gAy3mbJJoEITAdZBIue4bgacJR1uG4fN1iCqjjfpjXvA 3rwDq1s2ELW/kOE2BDR7RXL9PsA6ykuTzrmY3mwrHx+xEZOyV3l1oqsuJUhkzg== 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=1787673657; 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=xy4iQ7x9cgzqh6peUyF53fHErGdqyjGB92zah2yYXi8=; b=LhETr6OK9XM3W1q2GbliH6IJwmFkxZeGbt1KhTXBlHYsoZOah4al7pXogEllPsh3I7EhnP nFphAk33ZfsJrHMGW/DwN6w37338znAwvA7HvxzhTPz4WjI4d0ik8SE4ToUiU+E0SzWz/s OCEfTa7JvFQyVGIR36XKq4R1y98QYnXBKykwHw5/O8H/wheS9LfMwCrQVEJBW7V1IWEMPj eEbpSCtoOHwYt6WQ5h4q/ci3TRebA0dBnV9aiRO0eXEh969bf+jn8kzqEu82H20mqWYaih 1VInoaLCfX1tdDpwELprrQzyQV2s3YFKOdK7r0yYP4ZkFW9YJGhGH2dxeS0PxQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hTsvY2JrrzxZh for ; Tue, 25 Aug 2026 16:00:57 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 33098 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 25 Aug 2026 16:00:57 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 57a2373f86ac - releng/15.0 - 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/releng/15.0 X-Git-Reftype: branch X-Git-Commit: 57a2373f86acf8e2dbb334776044c7c1122a7432 Auto-Submitted: auto-generated Date: Tue, 25 Aug 2026 16:00:57 +0000 Message-Id: <6a8dbc39.33098.37799657@gitrepo.freebsd.org> The branch releng/15.0 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=57a2373f86acf8e2dbb334776044c7c1122a7432 commit 57a2373f86acf8e2dbb334776044c7c1122a7432 Author: Mark Johnston AuthorDate: 2026-08-24 14:57:16 +0000 Commit: Mark Johnston CommitDate: 2026-08-24 19:29:46 +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 a6a6ae68996c..50baff47e504 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. */ @@ -1411,10 +1356,19 @@ 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); } } @@ -1427,10 +1381,8 @@ 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 3dc3e54ee762..3df2701fabc4 100644 --- a/sys/kern/kern_exec.c +++ b/sys/kern/kern_exec.c @@ -1008,7 +1008,7 @@ 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;