From nobody Tue Jun 30 17:21:31 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 4gqVLN0RMWz6jYdv for ; Tue, 30 Jun 2026 17:21:32 +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 4gqVLM5L2Rz3s6Y for ; Tue, 30 Jun 2026 17:21:31 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1782840091; 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=JmAzxV7yufn9lXxy5MU2wOOjr3R0xVXqDqRfNXsgMgc=; b=WAMp1xRfSH2j8oKOQHwx4hKYfmns2kSLB4a9mn0M1YB7p5D5SbtRXRG5/J1L/iQjJq/9ol IXSL1MRFVOYsUoaPPHmdS6gDBpFRBgFYN9F+yOYYiZGTmGc4zut+uA8pfgWA9XEqizIew8 Ae38rwfqeDw9tqLU2jdsL1+ca7hUnCsTcxT3yDy1MPI3P0gwJExcjkX0m+zSdi0EJpbPus X9UuFU/1ux5KsVilkySFJJ7H2JX5BVMQFxLx0C/GNmQmrD4C2m0zlbzYxnFCRR79j6ItKl f+5Zjs0K34NfiRlpUpuFEW42/JJxNAU+LU9A8nMdjGDEe73U+pWiNy5ume+44g== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1782840091; a=rsa-sha256; cv=none; b=fo9s/KwrX+LuHtSNgveQJP1fBJ3ud+2XR3jCmm4DaFplPxCSxP7lNDAUHbuk/aQK99Jcua 0XQ0jyU17jNRYMgFOaez3Vd08fGPiGFwpRIkVdSSnmnDyB9ZrelPW7NlUc2c76JMIszkcO 8CqheIa2UdoB7wR1jPxTXZa6tiK6EGP9BvWqOxHPvdHg/qhg5uq04yvKm8P6Lnl5aMbJwi 70pTSIEgzi88uWa0QqVFPSI69qzfu7/AsbShLMvyuoLLxiMUx1ql8/A0DTBnjA2jjPSXbl flmAUZ1rRedbyRWj7MCJnvhQQAwhj/D7IOIqK+XRzgQ6lv96WBJ+mYXd+3IGHg== 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=1782840091; 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=JmAzxV7yufn9lXxy5MU2wOOjr3R0xVXqDqRfNXsgMgc=; b=BzyNKrKz1F59LTDFBjPIofjP+4bk39FU2VTUlOAT9YGHYJAK5OVPEfXv2050VAB7HaJoMX nqHx3tpPelVN3O+KtpzlGQ+IgZ35amVBxHz0JRF+aiwzdh7Ncf/Jjx0KKXgJQLM8PMdMMM rU4B9WN+yR6NsRDURC5/jxDZ8xS5LG4/tT5Klkxc54oH8G6QP0IXc+7hv6VPpuNQ44tBMi jmf6PHyuEd4E0JvSiVkFl7o4DISFWkHQc2JSqM/d7STPvA6Na2zj2p4/5SSFcm9URmcMAq kWziQGl6FNWePwHLgJfbJ6iQTekjM8J8UheSFdjKpq1e5PHfM36Tq/iX9Aj6cw== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gqVLM49yyztQ2 for ; Tue, 30 Jun 2026 17:21:31 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 45a20 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 30 Jun 2026 17:21:31 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 8d086f03b9be - releng/15.0 - posixshm: Fix handling of sendfile() with largepage objects 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/releng/15.0 X-Git-Reftype: branch X-Git-Commit: 8d086f03b9beebd1caa43549c824b269c8c6bda8 Auto-Submitted: auto-generated Date: Tue, 30 Jun 2026 17:21:31 +0000 Message-Id: <6a43fb1b.45a20.109f875@gitrepo.freebsd.org> The branch releng/15.0 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=8d086f03b9beebd1caa43549c824b269c8c6bda8 commit 8d086f03b9beebd1caa43549c824b269c8c6bda8 Author: Mark Johnston AuthorDate: 2026-06-24 19:57:00 +0000 Commit: Mark Johnston CommitDate: 2026-06-30 02:32:57 +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 | 22 ++++++++-- sys/vm/vm_page.c | 23 +++++----- tests/sys/posixshm/posixshm_test.c | 89 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 121 insertions(+), 13 deletions(-) diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c index 8ab03b5bff32..662d2e5e5c8c 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -326,6 +326,7 @@ 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 @@ -333,11 +334,27 @@ 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) { + struct pctrie_iter pages; + vm_page_t m; + bool removed __diagused; + + vm_page_iter_init(&pages, object); +restart: + VM_RADIX_FOREACH(m, &pages) { + if (!vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL)) { + pctrie_iter_reset(&pages); + goto restart; + } + removed = vm_page_iter_remove(&pages, 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", @@ -820,7 +837,7 @@ 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; @@ -868,7 +885,6 @@ 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 9de91d2503f2..4e42865a622d 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -4254,6 +4254,9 @@ 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)); @@ -4312,17 +4315,15 @@ 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); } /* @@ -4496,13 +4497,15 @@ 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 fbd15f079896..22e69255308f 100644 --- a/tests/sys/posixshm/posixshm_test.c +++ b/tests/sys/posixshm/posixshm_test.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include #include @@ -2150,6 +2151,93 @@ 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); + + 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) { @@ -2238,6 +2326,7 @@ 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());