From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794063662; b=UoNDHIohJ2Pp+fFk37QuzjuYGCkynlyAL+PXZf4SGpktUkKqpdYOJDgk4nj21unFdhyq /kWsrYsA1jIVwcbfWMRfMZOEdOOuTntNacoqhS111SCp0Qq2vyo3eSVy1fvicA+B5XVmU nngZZiqIgHBWbLa9ALJNJHnYULgGpR/f7bmirwCLLzE5I4gi856e+AS0W8SstaLgo3zKs j8EcmnCifPAHQxZAWNdF+p0bFCG+RTVm2z7cdvQJL8INyOdWa0oQYUA2OH2CnDxQVmemt P+fWfIRiMBummvEcmOD7iCNCN3B632+ztoFDDTuBMdKdLU1zdsFWngKFt1Nkge/AmIA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063662; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=OVao9QcNMcEjfVpV9hR9B73+qtczPgAL9/RzYbiezNw=; b=eQT6bfZ3iHsrZSOMI/BVk3BJfhUa3Gt4wSrvsJpBk6GI63BwRW5ymfFQOh12JHqjq49H o/NMODUTnvRU5+lHhd7DeSzB7IN5oWkByR1R4D+EJYd+A9XLWvcJjE8k/FhkK5ftHeXyI BernQndEi35yHxBoqm1bos4cpqN7i1P/Vwqn18PNLU4e9Tz9yGvToqxmKEs+kt2LsTSmd 693NtYByK91tH3QVT6xlPKXxmRKoJWP4wrRah9RAr5TKKql16NGb9QdE156Pb2WRHvN85 04fWk6MP9d4/imZuo5O8slM6vCTA4opsMPL2ah7hZZCpEq+2KX/q2vlyYT2G35kd4mg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=KxQsM7bi; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 14FC4606A9DA; Sat, 7 Nov 2026 15:01:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=KxQsM7bi Received: by smtp.kernel.org (Postfix) with ESMTPSA id 887A61F0089F; Sat, 7 Nov 2026 15:01:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063661; bh=OVao9QcNMcEjfVpV9hR9B73+qtczPgAL9/RzYbiezNw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KxQsM7bi2QTM03+twDK24c4KbQ1zDh7oh9YqMXlDVZ4OfC3y4NfDlTGChbaoQ0rKG LqRJmPsD+gYS8MiYg4zR5+0ngqlHXGyzjXA0TAIEMD58TnAsUYVakDpp9SbaOkinN4 wTRsjEId5DLAMDxecugdSMC3rZGuNXtHd/Wi4L2U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, co+ecaada42f806f629@bugs.sh, Xiang Mei , Alex Markuze , Ilya Dryomov , Sasha Levin Subject: [PATCH 6.18 775/869] ceph: fix integer overflow in the snap trace bounds check Date: Sat, 7 Nov 2026 08:57:37 -0500 Message-ID: <20261107134918.963243887@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit b3bf89767e3ca9506f1c7167cac97c41ec254d42 ] ceph_update_snap_trace() bounds the two encoded snapid arrays that follow a struct ceph_mds_snap_realm with sizeof(u64) * (num_snaps + num_prior_parent_snaps). Both counts come straight off the wire as __le32, so the addition is evaluated in unsigned int and wraps before sizeof(u64) promotes it to size_t: an MDS sending num_snaps = 1 and num_prior_parent_snaps = 0xffffffff makes the sum zero and the check degenerates to ceph_decode_need(&p, e, 0, bad), which always passes. dup_array() then reads num_snaps * 8 bytes past the end of the message front, which ceph_msg_new2() allocates at exactly front_len bytes. An unsolicited CEPH_MSG_CLIENT_SNAP reaches this from a malicious or compromised MDS with no client-side action, as do the snaptraces carried in an MDS reply and in a cap import. Compute the length with size_add()/size_mul() so it saturates at SIZE_MAX instead of wrapping, in the style fs/ceph/mdsmap.c already uses for num_export_targets. BUG: KASAN: slab-out-of-bounds in dup_array (include/linux/unaligned.h:28 fs/ceph/snap.c:500) Read of size 8 at addr ffff8880102a16c8 by task kworker/1:2/129 Workqueue: ceph-msgr ceph_con_workfn Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) dup_array (include/linux/unaligned.h:28 fs/ceph/snap.c:500) ceph_update_snap_trace (fs/ceph/snap.c:836) ceph_handle_snap (fs/ceph/snap.c:1155) mds_dispatch (fs/ceph/mds_client.c:7234) ceph_con_process_message (net/ceph/messenger.c:1424) ceph_con_v1_try_read (net/ceph/messenger_v1.c:1430) ceph_con_workfn (net/ceph/messenger.c:1576) process_one_work (kernel/workqueue.c:3396) worker_thread (kernel/workqueue.c:3479 kernel/workqueue.c:3560) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) ... The buggy address is located 0 bytes to the right of allocated 72-byte region [ffff8880102a1680, ffff8880102a16c8) Cc: stable@vger.kernel.org Fixes: 963b61eb041e ("ceph: snapshot management") Reported-by: co+ecaada42f806f629@bugs.sh Assisted-by: LLM Signed-off-by: Xiang Mei Reviewed-by: Alex Markuze Signed-off-by: Ilya Dryomov Signed-off-by: Sasha Levin --- fs/ceph/snap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index c65f2b202b2b3..00cfcef5fbb25 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -788,6 +788,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, struct ceph_snap_realm *first_realm = NULL; struct ceph_snap_realm *realm_to_rebuild = NULL; struct ceph_client *client = mdsc->fsc->client; + size_t snaps_len; int rebuild_snapcs; int err = -ENOMEM; int ret; @@ -802,8 +803,10 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, ceph_decode_need(&p, e, sizeof(*ri), bad); ri = p; p += sizeof(*ri); - ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) + - le32_to_cpu(ri->num_prior_parent_snaps)), bad); + snaps_len = size_mul(size_add(le32_to_cpu(ri->num_snaps), + le32_to_cpu(ri->num_prior_parent_snaps)), + sizeof(u64)); + ceph_decode_need(&p, e, snaps_len, bad); snaps = p; p += sizeof(u64) * le32_to_cpu(ri->num_snaps); prior_parent_snaps = p; -- 2.53.0