From nobody Tue Aug 25 15:59:53 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 4hTstL1XQsz6pbPC for ; Tue, 25 Aug 2026 15:59:54 +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 4hTstK3Q5Rz429F for ; Tue, 25 Aug 2026 15:59:53 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1787673593; 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=nFzx4ZYZhWtbM1jeSpw2Vsz+FiF+vVcCAK6LudfvgTU=; b=MdcFhKD6qhVMfVUrOtnuSp/zuRdMBZVKctaoE8uOTuPQhqYRjuJfodwhyPEJGHWmAU20Sv zz3pnuz7sFueSZePiXRrSGz50bGbxO5aqyOK/VdZcgMMzPRWmA28uWej/HEzk0tMu+f8WW p0s9ZFtm3gYaYFxtd2hSMr+cJj+8Ky6gKry9/DNz2CaUpmEEhYLK93lsIyYAaZGM2sBd+I wmCAr5ph8brRckWlb6yLak+BtUrmoJG4+hMUFOrF10/RcS/3DHW1GcPAYrRC/pd0XGZGcA zPIm6OYC2yaxGoUqYrUx+mtcLtj9biri2tL/A2uh81pTohPO1Jihwz9pnyC5lQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1787673593; a=rsa-sha256; cv=none; b=VunV1kuBvufUYZAz/VWzNFAB4cJc05QVQmFu9OceBCnrT4DlCAM6PUqfMNR3DFV5CvxRaB xrd8sakfyMHvY7X85bxqr5N4cPTQgraxTNQ2iYp19Nrb2nRawNx/gUgfRcKZjIPqtkFQR8 YbO5RgiQ4GLXt08/TnJ8kVBWihJgbkoyqiNSvhvavW9KgurKrxrnC30VRG5j4zozOVJ+l4 zwmkXYgone02YHodZFQBg8oO0aUPNOJqmHBjOzaL4yImNAIA3LIRk0bg+S8exXyPhOfcOU 9d83Y9zaw+bdfDyOFWLUEWML5tqFzCo2hJ2kARiaSZIvJA5Q+jlt6pesMbGtSQ== 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=1787673593; 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=nFzx4ZYZhWtbM1jeSpw2Vsz+FiF+vVcCAK6LudfvgTU=; b=XdyMdHSBS9uXyfloDf3aJqP/yoHJDPLNxIg6281eIuXCduEiigBtrbYBYsV8EaIMSGtLH1 CmXNE+2EF7iDiN9YRRiRDbWlU+o8olO2Okkz86HSJLeUQff5/G7Yd8SFUmmZW+1QT8wNCN XWbke3euPSu2GaR5u+NS2wFtlBZTodOrsIAGJDdgg9XnDhyt8goYxe9wang4drk26qQy+/ +Sb6Uvk5764j1N4fjxZP8/d31tGjKyj+pWkBFUU23dTFvh2cYDKCowlEC5rg77Uv9TJbOP yxAzDtndAIKu7vvz84kK6Ajw/V3Sgmc4CXipOmmimfh6Y7USJKdJOjwqPJR2iA== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hTstK1kllzy7r for ; Tue, 25 Aug 2026 15:59:53 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 313ba by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 25 Aug 2026 15:59:53 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 5990860ca841 - stable/15 - posixshm: Fix a TOCTOU race in the FIOSSHMLPGCNF 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: 5990860ca841fddaef9acbb7e2cbbd372ce10081 Auto-Submitted: auto-generated Date: Tue, 25 Aug 2026 15:59:53 +0000 Message-Id: <6a8dbbf9.313ba.ddfabed@gitrepo.freebsd.org> The branch stable/15 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=5990860ca841fddaef9acbb7e2cbbd372ce10081 commit 5990860ca841fddaef9acbb7e2cbbd372ce10081 Author: Mark Johnston AuthorDate: 2026-08-24 18:15:38 +0000 Commit: Mark Johnston CommitDate: 2026-08-25 15:47:13 +0000 posixshm: Fix a TOCTOU race in the FIOSSHMLPGCNF handler The check for whether shm_lp_psind was assigned was unlocked. This race can be exploited to create an object with psind==2 but with only pagesizes[1] worth of pages populated. This in turn can be used to escalate privileges. Fix this by acquiring the rangelock earlier. In shm_mmap_large(), assert that we hold the rangelock. In shm_write(), annotate an unlocked load of shm_lp_psind. Approved by: so Security: FreeBSD-SA-26:63.posixshm Security: CVE-2026-58094 Reported by: tsune of GMO Cybersecurity by Ierae, Inc. working with TrendAI Zero Day Initiative Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D59104 --- sys/kern/uipc_shm.c | 27 +++++++++++++++++---------- sys/sys/mman.h | 2 +- 2 files changed, 18 insertions(+), 11 deletions(-) diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c index 8341364f4d16..fa80eabc39a3 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -512,8 +512,6 @@ shm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, if (error) return (error); #endif - if (shm_largepage(shmfd) && shmfd->shm_lp_psind == 0) - return (EINVAL); foffset_lock_uio(fp, uio, flags); if (uio->uio_resid > OFF_MAX - uio->uio_offset) { /* @@ -535,7 +533,9 @@ shm_write(struct file *fp, struct uio *uio, struct ucred *active_cred, else rl_cookie = shm_rangelock_wlock(shmfd, uio->uio_offset, MAX(newsize, uio->uio_offset)); - if ((shmfd->shm_seals & F_SEAL_WRITE) != 0) { + if (shm_largepage(shmfd) && shmfd->shm_lp_psind == 0) { + error = EINVAL; + } else if ((shmfd->shm_seals & F_SEAL_WRITE) != 0) { error = EPERM; } else { error = 0; @@ -592,18 +592,23 @@ shm_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, if (!shm_largepage(shmfd)) return (ENOTTY); conf = data; + rl_cookie = shm_rangelock_wlock(shmfd, 0, OFF_MAX); if (shmfd->shm_lp_psind != 0 && - conf->psind != shmfd->shm_lp_psind) + conf->psind != shmfd->shm_lp_psind) { + shm_rangelock_unlock(shmfd, rl_cookie); return (EINVAL); + } if (conf->psind <= 0 || conf->psind >= MAXPAGESIZES || - pagesizes[conf->psind] == 0) + pagesizes[conf->psind] == 0) { + shm_rangelock_unlock(shmfd, rl_cookie); return (EINVAL); + } if (conf->alloc_policy != SHM_LARGEPAGE_ALLOC_DEFAULT && conf->alloc_policy != SHM_LARGEPAGE_ALLOC_NOWAIT && - conf->alloc_policy != SHM_LARGEPAGE_ALLOC_HARD) + conf->alloc_policy != SHM_LARGEPAGE_ALLOC_HARD) { + shm_rangelock_unlock(shmfd, rl_cookie); return (EINVAL); - - rl_cookie = shm_rangelock_wlock(shmfd, 0, OFF_MAX); + } shmfd->shm_lp_psind = conf->psind; shmfd->shm_lp_alloc_policy = conf->alloc_policy; shmfd->shm_object->un_pager.phys.data_val = conf->psind; @@ -1575,7 +1580,7 @@ out: static int shm_mmap_large(struct shmfd *shmfd, vm_map_t map, vm_offset_t *addr, vm_size_t size, vm_prot_t prot, vm_prot_t max_prot, int flags, - vm_ooffset_t foff, struct thread *td) + vm_ooffset_t foff, struct thread *td, void *rl_cookie) { struct vmspace *vms; vm_map_entry_t next_entry, prev_entry; @@ -1583,6 +1588,8 @@ shm_mmap_large(struct shmfd *shmfd, vm_map_t map, vm_offset_t *addr, int docow, error, rv, try; bool curmap; + rangelock_cookie_assert(rl_cookie, RA_LOCKED); + if (shmfd->shm_lp_psind == 0) return (EINVAL); @@ -1758,7 +1765,7 @@ shm_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t objsize, if (shm_largepage(shmfd)) { writecnt = false; error = shm_mmap_large(shmfd, map, addr, objsize, prot, - maxprot, flags, foff, td); + maxprot, flags, foff, td, rl_cookie); } else { if (writecnt) { vm_pager_update_writecount(shmfd->shm_object, 0, diff --git a/sys/sys/mman.h b/sys/sys/mman.h index ba478bc71c7c..e15cc4380b5b 100644 --- a/sys/sys/mman.h +++ b/sys/sys/mman.h @@ -293,7 +293,7 @@ struct shmfd { int shm_flags; int shm_seals; - /* largepage config */ + /* largepage config, synchronized by the rangelock */ int shm_lp_psind; int shm_lp_alloc_policy; };