From nobody Tue Aug 25 15:59:19 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 4hTssn3y0fz6pZqc for ; Tue, 25 Aug 2026 15:59:25 +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 4hTssm5phhz41SM for ; Tue, 25 Aug 2026 15:59:24 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1787673564; 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=tUW83YejQIWQGk+YytODdjN0mVLnl8Rx5ks5ASck1/w=; b=mKtpi91KbVoDK42gVqWppn3OzAdw9+T4Dldv/jIl1/DCL1txKuuQJY5M9VdiPT5qQtPQDO 42xlfuAJ0rYc7V8PY46pbQDVLyEjkhZ3M26+aROLTWZwZJc6UHmX2SgOfwU3bU6XkWdI2z 1pzUcmM0WrwPwPtiEcMSIc2m4Y6KVLFqehydcqhzjuj5kzUH0jrITd0ZvtaIpbw6UZ609V ik4Esn9cOaLtQIXJgyuzx2SQQsV0Q/oXtYsztnwpmEgN8BcM7aZFdBJTIfFMyGtTjsNifP Z09S/RPTtcUSVnaA6af/lGD1Yl9iQBd4qsMfNGVrqy5E8HY7hc0F7kvolTg5Ew== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1787673564; a=rsa-sha256; cv=none; b=VaSMzqCLo5VxZK1wAIqcSzmTYUia/mWA5AHCNPf8wzuEkDCuzKQ/dpXTIPKO0M4SBpk6qg fKdMt1yf4V9kXRi8+r7mOZkNblgMuHucJK9BTwIttMdMEhQKGuKB8DRrn35eGoh4oKmy+L zJRXJTxfhUPNANcd5yiFwQYktECiVCcEErbFwNqCEG9noFQCQFCtI0uiJMWpegQJTfDa6r wKW2/ABvyDom4T5P8hazT3c2oFllUF3GuRXf0KLFk39QD54GMMdqykK4PW4XMtPREtGZ+/ qUSsFBRFDvpDpG/bwNwwoy+jKudLojGdau/w1e8NipXVVPQ9htoIwEzUxLF5Wg== 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=1787673564; 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=tUW83YejQIWQGk+YytODdjN0mVLnl8Rx5ks5ASck1/w=; b=qO/K7ZjYFo7qtxUcyW7gXHJQWMF+nsPSuwpCxL0ljkd/DoGJkH95u38FesJJNM5LolOu3+ iEm7fa2EhNcioP65gul7JUuMrATJ/AMG8EYeIb7m6mV4HaL2ZS/ioDW9UXenVYyWqCZroD pagdnDdvxB8udn3sQTvYqXFA0lOvrPSslcClyU6VOE5tBMVdDk81hRqqLJk/FG10tw10+c Hf+NpPqBtihcRtga3pXjKz5aZt71W2E7sjZ6x3zTNq3fSo5TRFIxEBJ2WfmpJiLEyA79Uv dUOKH6hVwxhSmIYAT439XqojTx8Zxvxh0uXseyWTxORbbBpQGgib7fi7p0SFSw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hTssm4v6yzy7p for ; Tue, 25 Aug 2026 15:59:24 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 31141 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 25 Aug 2026 15:59:19 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mark Johnston Subject: git: cbf3fe8549b6 - main - 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/main X-Git-Reftype: branch X-Git-Commit: cbf3fe8549b68745bddd6c6ee4a0f3233eacbe85 Auto-Submitted: auto-generated Date: Tue, 25 Aug 2026 15:59:19 +0000 Message-Id: <6a8dbbd7.31141.70e8d9f2@gitrepo.freebsd.org> The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=cbf3fe8549b68745bddd6c6ee4a0f3233eacbe85 commit cbf3fe8549b68745bddd6c6ee4a0f3233eacbe85 Author: Mark Johnston AuthorDate: 2026-08-24 14:57:16 +0000 Commit: Mark Johnston CommitDate: 2026-08-25 15:46:23 +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 bfa8a217235e..6c405d53486b 100644 --- a/sys/dev/hwpmc/hwpmc_mod.c +++ b/sys/dev/hwpmc/hwpmc_mod.c @@ -218,7 +218,6 @@ 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); @@ -1033,60 +1032,6 @@ 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. */ @@ -1450,10 +1395,19 @@ 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); } } @@ -1466,10 +1420,8 @@ 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 352170d4f6f0..7871ac9b86fa 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;