From nobody Tue Jun 30 17:21:04 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 4gqVKr5SXPz6jY6C for ; Tue, 30 Jun 2026 17:21:04 +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 4gqVKr2J2Pz3rG1 for ; Tue, 30 Jun 2026 17:21:04 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1782840064; 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=Dghh36/3eNykcbm/gZ9gew+hAxfdL6ADrFF2F8UoZlo=; b=A4Ejar0ghWfxNUzPkRRf5BHLSPJB7z+7LXonMEcI0pDFyO/Bl5Q1zWXcmsZ+m2affMeN+8 sxv+sx3orwYsE/9YgUnoYXTuqjJh3PC0svW7kHoZxYAH0WrsXVaHDF6pta/+xCzRT3Thrn Vh+orB5fVLmDz1MWz8kRxNtGI+fLAWkBJ955JeqsF+yX3iFQVlHpg/SYxABe1mjM9uJQnC EIICdFWJvThs77c23RZEAgzqnlLklyLR4b/1Psn16bHPA3my0Upex0hnXtYnnUdb6X27+E yzt/F+lsBjn6mRiJZI7koVT9s1/i7y9pHD1lUXkdRO8ddmRJOv0D2rQQxE0gNQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1782840064; a=rsa-sha256; cv=none; b=orwreQiOM6HPHGKNd4nxdj72oqQsfrXJlI0W2PSF+llCZoTAzrNDVA5ybok5VKtOzYKTIQ h4tndjXa/rEZUIwyeFv5Cw6tqYt+WuJbgNx6hQd46XkiP6RKpkkYUpVEnvSSJIUOUQp9AB oXX7zZINHavLgI0Rjty9Hnd4IXFNQ1AQos5EeBEOS1nRMGJiRV7tr00+7pbE9kI3fOWNKy JgsWFdq1mUI2XIdAmPl3iwhLG6M7h74xXQ+zSZesceajH8G2al1KcG/QcobWe7byoToXAW 5cdQXrFBv/jEkjOlZFbbFSVQKqhg+RBOEh8V+GRM+r7rfPsaMvO9n1SX6GCekw== 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=1782840064; 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=Dghh36/3eNykcbm/gZ9gew+hAxfdL6ADrFF2F8UoZlo=; b=OH7684fmPkSGeLC5Wu7aRf+dCYN2PdwCWViN4mxDH3Qn+SLiJnVmiXs5kVJjfwxyNvwUJ1 2hiVXv80YoOWb7hAdk6mOIT8LUPl/8xj6Fl13J6GCW4pr+uItU5dv3Qx2rXf/0yrHxayzF eN91OdZSXuDVeWpdgFHX4P0Mv23nonPC4qh39oWMH/zMSAd5UuNVKr3ztsnV1kihWnSIHa M6xMmOxb7vBCrO/4mV5HzZSgCUDTj012f8UDdDJFHEwXSJJEkS+W0khPNdj+B1AlNRm5Uk QA8f7sS9VYfQqiZmwDYFB5P6/0vVE69trqkOB3BnGL4gT2PEshIP+gFSuDxTog== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gqVKr1Ftnzt05 for ; Tue, 30 Jun 2026 17:21:04 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 44fb2 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Tue, 30 Jun 2026 17:21:04 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: 0848cdea83fd - releng/14.4 - 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/releng/14.4 X-Git-Reftype: branch X-Git-Commit: 0848cdea83fd46a5f23f813e3069b11df31a7233 Auto-Submitted: auto-generated Date: Tue, 30 Jun 2026 17:21:04 +0000 Message-Id: <6a43fb00.44fb2.7ad2ccd0@gitrepo.freebsd.org> The branch releng/14.4 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=0848cdea83fd46a5f23f813e3069b11df31a7233 commit 0848cdea83fd46a5f23f813e3069b11df31a7233 Author: Mark Johnston AuthorDate: 2026-06-24 19:57:00 +0000 Commit: Mark Johnston CommitDate: 2026-06-29 19:17:30 +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 8542510299a9..937784e5e860 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; @@ -904,7 +918,6 @@ 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 c792a85de9e3..dccc5add12a9 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 @@ -2151,6 +2152,93 @@ 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) { @@ -2239,6 +2327,7 @@ 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());