From nobody Tue Jun 30 17:19:55 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 4gqVJX5yg4z6jXdl for ; Tue, 30 Jun 2026 17:19:56 +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 "YR1" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4gqVJX21Zyz3pV8 for ; Tue, 30 Jun 2026 17:19:56 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1782839996; 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=kuibJMS4ZVOo7l46hMOeQv13uqYqIS7kk15cLAW4pMQ=; b=SFuBCRD3dxNbVTUs8aw0Nhrcczdke8b6r35B3jafLZ02tTWHn5h3nb08N0zJ+6OiSktpPl QGqnanpw13gBDxrWmj1i5Khp+GtbYCi/0w4gzXbSXqLKHy7Cphzvw1bQE70TvKRrtFGXCx A9nuLzmeBdigC3jRaLovyJD7eI1mE4d8Aw0T/0hkKxuQOz0R1G3KSoc7nppROHIZOCOoaI TS97p7+9SMicdMmHBE1/19YhTeAz0MuFldhPNdFzc/2x4vmv4wmE0LDJ5M7JU2K7WbSqsD ywBw/Lo6bY6wm59JLlw2Ogg5vJrnMHb/F2ksKJBAxQXcNhmHprTjggFpbmMf3w== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1782839996; a=rsa-sha256; cv=none; b=pM+XdUzzhzZPWegBgOGG9q5F1OQ2hDGeoqVBK8vet/ZrUC10dBTHiTYckwqZMNyOqyhkuM Makk36RTbyI/idTWvJMI0xd/R7vGE/8ykdOnE6/iIyxhBnsaAsrGB4tCLY8LG4tn9Ba/xj yvLDFo6j1kSzMW2/ciG130RWqLRckRcDurjeOCbIFf5yeDrVe1nZROzWa8p6tYbQT0QFeq W6+RV1EOLKIPujrrqOoPErc7LEouxSuOPfN1dnv23VPZzRnq6kh7rpEGjvLD12Tz9adxyC 33O/FGSo8KBNbDrOzoywgaOSyYf6Fx9Ce843aqaR3O1CD486G/s/nLD+GljO5g== 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=1782839996; 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=kuibJMS4ZVOo7l46hMOeQv13uqYqIS7kk15cLAW4pMQ=; b=taWxJT2EcaDJz4UzMdnDgjqaQBIvF3NAAvFUk30gvapoWk3MdgqHJd48Eo0DUqQchPvSEI lcQTP54Viw/IOKcAJ7YJgfawCQyDU6sKSV04Mg1aLaTGiC8apzQKFoqW7LKS4IgMMTKyYM gBbaQXwbs7bbxrUxJFWwEVHI7T8HdruDsid+GopIiM/8PNfNSYrhLoTxwP8dOGSrKCpcsu ZRQe4RRrKQwiFD7IQl7p0ozsZYdqeaQmqUoteU7cjCtEKFFpGadwX2XCw6/Dvngk6bu5xn KhAVOjEMoTPi2jWKv9s+UrEQpI0gTGDdAuopyElKMXBO/Qv2hU78fWrZhzy+tQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gqVJW6YdHzt9c for ; Tue, 30 Jun 2026 17:19:55 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 444a7 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 30 Jun 2026 17:19:55 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: f30052c16dba - stable/14 - posixshm: Fix handling of sendfile() with largepage objects 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/14 X-Git-Reftype: branch X-Git-Commit: f30052c16dba54e63a5e9dcd81f5a58a4eee4684 Auto-Submitted: auto-generated Date: Tue, 30 Jun 2026 17:19:55 +0000 Message-Id: <6a43fabb.444a7.6bdd809e@gitrepo.freebsd.org> The branch stable/14 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=f30052c16dba54e63a5e9dcd81f5a58a4eee4684 commit f30052c16dba54e63a5e9dcd81f5a58a4eee4684 Author: Mark Johnston AuthorDate: 2026-06-24 19:57:00 +0000 Commit: Mark Johnston CommitDate: 2026-06-30 17:00:22 +0000 posixshm: Fix handling of sendfile() with largepage objects sendfile(2) can transmit POSIX shared memory objects. Typically it will look up and wire each page before sending it to a socket; once transmission is complete, the page is unwired and typically released back into the page queues. sendfile() has an advisory flag, SF_NOCACHE, which means, "try to free the page once transmission is complete." This is implemented in vm_page_release(), which expects to operate on managed pages. Pages belonging a largepage object are de-facto wired not explicitly so. Thus, vm_page_release() will unwire and, having found no additional references, free the page. Because mappings of largepage objects are unmanaged, userspace can still access the now freed page. Fix the problem by explicitly wiring largepage pages. Make the VM object destructor responsible for unwiring and freeing them. Add a regression test. Approved by: so Security: FreeBSD-SA-26:44.posixshm Security: CVE-2026-49427 Reported by: Chris Jarrett-Davies Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D57832 --- sys/kern/uipc_shm.c | 19 ++++++-- sys/vm/vm_page.c | 23 +++++----- tests/sys/posixshm/posixshm_test.c | 89 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 118 insertions(+), 13 deletions(-) diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c index f302bc305f86..9c2f91ffe347 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -323,6 +323,7 @@ static void shm_largepage_phys_ctor(vm_object_t object, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred) { + object->flags |= OBJ_PG_DTOR; } static void @@ -330,11 +331,24 @@ shm_largepage_phys_dtor(vm_object_t object) { int psind; + VM_OBJECT_ASSERT_WLOCKED(object); + psind = object->un_pager.phys.data_val; if (psind != 0) { + vm_page_t m, mtmp; + bool removed __diagused; + +restart: + TAILQ_FOREACH_SAFE(m, &object->memq, listq, mtmp) { + if (!vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL)) { + goto restart; + } + removed = vm_page_remove(m); + KASSERT(!removed, ("%s: page %p not wired", __func__, m)); + vm_page_unwire(m, PQ_NONE); + } atomic_subtract_long(&count_largepages[psind], object->size / (pagesizes[psind] / PAGE_SIZE)); - vm_wire_sub(object->size); } else { KASSERT(object->size == 0, ("largepage phys obj %p not initialized bit size %#jx > 0", @@ -856,7 +870,7 @@ shm_dotruncate_largepage(struct shmfd *shmfd, off_t length, void *rl_cookie) if ((shmfd->shm_seals & F_SEAL_GROW) != 0) return (EPERM); - aflags = VM_ALLOC_NORMAL | VM_ALLOC_ZERO; + aflags = VM_ALLOC_NORMAL | VM_ALLOC_ZERO | VM_ALLOC_WIRED; if (shmfd->shm_lp_alloc_policy == SHM_LARGEPAGE_ALLOC_NOWAIT) aflags |= VM_ALLOC_WAITFAIL; try = 0; @@ -912,7 +926,6 @@ shm_dotruncate_largepage(struct shmfd *shmfd, off_t length, void *rl_cookie) object->size += OFF_TO_IDX(pagesizes[psind]); shmfd->shm_size += pagesizes[psind]; atomic_add_long(&count_largepages[psind], 1); - vm_wire_add(atop(pagesizes[psind])); } return (0); } diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c index 178b104ab95f..284895658651 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -4121,6 +4121,9 @@ vm_page_unwire_managed(vm_page_t m, uint8_t nqueue, bool noreuse) { u_int old; + KASSERT(nqueue < PQ_COUNT, + ("vm_page_unwire: invalid queue %u request for page %p", + nqueue, m)); KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("%s: page %p is unmanaged", __func__, m)); @@ -4179,17 +4182,15 @@ vm_page_unwire_managed(vm_page_t m, uint8_t nqueue, bool noreuse) void vm_page_unwire(vm_page_t m, uint8_t nqueue) { - - KASSERT(nqueue < PQ_COUNT, - ("vm_page_unwire: invalid queue %u request for page %p", - nqueue, m)); + KASSERT(nqueue < PQ_COUNT || nqueue == PQ_NONE, + ("%s: invalid queue %u request for page %p", __func__, nqueue, m)); if ((m->oflags & VPO_UNMANAGED) != 0) { if (vm_page_unwire_noq(m) && m->ref_count == 0) vm_page_free(m); - return; + } else { + vm_page_unwire_managed(m, nqueue, false); } - vm_page_unwire_managed(m, nqueue, false); } /* @@ -4363,13 +4364,15 @@ vm_page_release_toq(vm_page_t m, uint8_t nqueue, const bool noreuse) void vm_page_release(vm_page_t m, int flags) { - vm_object_t object; - - KASSERT((m->oflags & VPO_UNMANAGED) == 0, - ("vm_page_release: page %p is unmanaged", m)); + if ((m->oflags & VPO_UNMANAGED) != 0) { + vm_page_unwire(m, PQ_NONE); + return; + } if ((flags & VPR_TRYFREE) != 0) { for (;;) { + vm_object_t object; + object = atomic_load_ptr(&m->object); if (object == NULL) break; diff --git a/tests/sys/posixshm/posixshm_test.c b/tests/sys/posixshm/posixshm_test.c index 20f44693b45d..24a90133f4d9 100644 --- a/tests/sys/posixshm/posixshm_test.c +++ b/tests/sys/posixshm/posixshm_test.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -2149,6 +2150,93 @@ ATF_TC_BODY(largepage_reopen, tc) "close failed; errno=%d", errno); } +static unsigned char +largepage_sendfile_expected(size_t off) +{ + + return ((unsigned char)(off * 131 + (off >> 8))); +} + +ATF_TC_WITHOUT_HEAD(largepage_sendfile); +ATF_TC_BODY(largepage_sendfile, tc) +{ + static const int flags[] = { 0, SF_NOCACHE }; + char *addr; + off_t sbytes; + size_t ps[MAXPAGESIZES]; + int error, fd, pscnt, sd[2], status; + pid_t child; + + pscnt = pagesizes(ps, true); + + for (int i = 1; i < pscnt; i++) { + for (int fi = 0; fi < (int)nitems(flags); fi++) { + fd = shm_open_large(i, SHM_LARGEPAGE_ALLOC_DEFAULT, + ps[i]); + addr = mmap(NULL, ps[i], PROT_READ | PROT_WRITE, + MAP_SHARED, fd, 0); + ATF_REQUIRE_MSG(addr != MAP_FAILED, + "mmap(%zu bytes) failed; error=%d", ps[i], errno); + + /* Fill with a verifiable pattern. */ + for (size_t j = 0; j < ps[i]; j++) + addr[j] = largepage_sendfile_expected(j); + + ATF_REQUIRE(socketpair(PF_LOCAL, SOCK_STREAM, 0, + sd) == 0); + + child = fork(); + ATF_REQUIRE_MSG(child != -1, + "fork() failed; error=%d", errno); + if (child == 0) { + char buf[BUFSIZ]; + ssize_t len; + size_t off, resid; + + (void)close(sd[0]); + off = 0; + for (resid = ps[i]; resid > 0; resid -= len) { + len = read(sd[1], buf, sizeof(buf)); + if (len <= 0) + _exit(1); + for (ssize_t k = 0; k < len; k++) { + if ((unsigned char)buf[k] != + largepage_sendfile_expected( + off + k)) + _exit(2); + } + off += len; + } + _exit(0); + } + ATF_REQUIRE(close(sd[1]) == 0); + + sbytes = 0; + error = sendfile(fd, sd[0], 0, ps[i], NULL, &sbytes, + flags[fi]); + ATF_REQUIRE_MSG(error == 0, + "sendfile() failed; error=%d flags=%#x", + errno, flags[fi]); + ATF_REQUIRE_MSG(sbytes == (off_t)ps[i], + "sendfile() short; sbytes=%jd expected=%zu flags=%#x", + (intmax_t)sbytes, ps[i], flags[fi]); + + ATF_REQUIRE(close(sd[0]) == 0); + + ATF_REQUIRE_MSG(waitpid(child, &status, 0) == child, + "waitpid() failed; error=%d", errno); + ATF_REQUIRE_MSG(WIFEXITED(status), + "child killed by signal %d", WTERMSIG(status)); + ATF_REQUIRE_MSG(WEXITSTATUS(status) == 0, + "child exited with status %d (flags=%#x)", + WEXITSTATUS(status), flags[fi]); + + ATF_REQUIRE(munmap(addr, ps[i]) == 0); + ATF_REQUIRE(close(fd) == 0); + } + } +} + ATF_TC_WITHOUT_HEAD(largepage_truncate); ATF_TC_BODY(largepage_truncate, tc) { @@ -2237,6 +2325,7 @@ ATF_TP_ADD_TCS(tp) ATF_TP_ADD_TC(tp, largepage_pkru); #endif ATF_TP_ADD_TC(tp, largepage_reopen); + ATF_TP_ADD_TC(tp, largepage_sendfile); ATF_TP_ADD_TC(tp, largepage_truncate); return (atf_no_error());