From nobody Tue Aug 25 16:00:04 2026 X-Original-To: dev-commits-src-branches@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 4hTstY3Kdhz6pbYD for ; Tue, 25 Aug 2026 16:00:05 +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 4hTstY12bfz42ZL for ; Tue, 25 Aug 2026 16:00:05 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1787673605; 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=T4/92Ls3yopj1mYc/+UzPUDcm524qanJRjjawWo0RLw=; b=wRudoL9BEBQm5wy9RMGoC1Dcm0iaJRUBkBDz1AQAD1yjemf+H6rmo8e3V4lv54DKyj4ovy Z1al82LOhRoZh8lmI7JLUtcD73bWE0FwIWzgvGHuR85z592o9DOJGtM+AAf+1KRW3T6/86 X66WP90hZJzC8s5gXl0NTBKk89/FTXKfjLojs16TJ9zK7djv0tHO1kY9YXUvDqXkdV+KF9 BWsaq3uKPy/lAIkOKOA0mLsTGmMNSyUMgjrnmSm8gF/6RR42JIu18HE+ZuQJ3I5o4x4Wya UyK0jeuKbbjOxMPUfLSnalGLMOrT2ypxDvSYd5cYckmNk/LV9uXqXAlAoF8Hpg== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1787673605; a=rsa-sha256; cv=none; b=oiXy5WDdaPeiz7JwCOkEYu380tSlnr9Ii5xSshuYWDl4FiTRqYLjuodWdFx4S7PjOKEyRB RLa+nU69kEdYIFJpFMx3m2uf9rH+DoIUI3mzCuzQgOOrB/AxQCBnqmvP2iKFLlmAu/gcCY BBc6A/t34haRsLHT3Al+up9yPoN14H3Z2FxfoaV60sTFMZR/eN/cYaQ9C+2/MuvkvzBzIG AItJKkl8CiHVhfuM0BGCQcrQQY0Uzh9QsHUBHdOo5Sol3p6BZo3hSRhasCgoe1l+scVW9J 2GsPJg46jtnk6wuZkFfwfFZWq0hJ/ohqeu9BLHB6ssKweAKtZP3PATqhHoSL7g== 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=1787673605; 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=T4/92Ls3yopj1mYc/+UzPUDcm524qanJRjjawWo0RLw=; b=yUKQwLbhJsh1iK97sAjPK6SPQmfDzwHd73Th9RjSG1g037gYmEdJUua1KBqNHg+4c04hW4 mKUw73omIvvGz6202DawMSMkvfL5Eg3jrXHfA/cG2wAAwmxufg5WUGlYCXEUurPaGsY6hZ rg1JbrOicql7BrLhYSxNae6pvl5Z8CyzSnjC0tlqcAGesAGBV868545UxjD8+Ns0U4Tcel /2B8cnYGRzozeSwj42O8CmDJpToQqmQ115R5JlQZ+s8RlsrWERsuG0jSc85VPB9XWj5Tnw vD6RL6dEDQp2iDmmdMHiXzrqTd33YXHaqOEMZ+s2BrNXWJqTdfCDh7fPcXFpNQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hTstX6rdzzxs4 for ; Tue, 25 Aug 2026 16:00:04 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 311f5 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 25 Aug 2026 16:00:04 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 6bfd894c8b14 - stable/14 - posixshm: Fix a TOCTOU race in the FIOSSHMLPGCNF handler List-Id: Commits to the stable branches of the FreeBSD src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-branches List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-branches@freebsd.org Sender: owner-dev-commits-src-branches@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/14 X-Git-Reftype: branch X-Git-Commit: 6bfd894c8b14fe781248aa94e3b7b29dd324b106 Auto-Submitted: auto-generated Date: Tue, 25 Aug 2026 16:00:04 +0000 Message-Id: <6a8dbc04.311f5.adabbd@gitrepo.freebsd.org> The branch stable/14 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=6bfd894c8b14fe781248aa94e3b7b29dd324b106 commit 6bfd894c8b14fe781248aa94e3b7b29dd324b106 Author: Mark Johnston AuthorDate: 2026-08-24 18:15:38 +0000 Commit: Mark Johnston CommitDate: 2026-08-25 15:58:57 +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 9c2f91ffe347..3cb4b9734066 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -506,8 +506,6 @@ 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) { /* @@ -529,7 +527,9 @@ 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; @@ -586,18 +586,23 @@ 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; @@ -1591,7 +1596,7 @@ 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; @@ -1599,6 +1604,8 @@ 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); @@ -1763,7 +1770,7 @@ 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 d444f02d3c89..0717edf6a926 100644 --- a/sys/sys/mman.h +++ b/sys/sys/mman.h @@ -291,7 +291,7 @@ 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; };