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=1794351597; b=Xq+KDUUgglNQ+vbX5xsnbku61+ebnYDK0iAP2tZYmCJUYTwCLeuc38r1IGYlB6O72MQW fAhyff8QCf5sE1isPJ81PFB4rE85Sz/j0qQ9Iv9UYOWSq+0I9zbC91x38vo/emnrM3L9j ka5L4V+va8jj1gvvKSTMFihCuacsL3WRgIlzT/fASaV57wAkbvE0qnYS0h9MQF7bmcGho yJPe0exdnPeYfibMMBjjOLuqfFBmLgeOQUA/Yshs0yq3excaCirHOTlyy/CWIFnbUJsYQ crXNfl6AQeVrKQOIyy3894yPmDELJMYVmRM8KJIjQG0CbQLQVqpIHuDVgz70PEpUqTg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794351597; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=bFIpRPx2YZGBGUB7lpvwu3PR8rwLsePjl+Y2HF5Tgp0=; b=1nI8L8ZDGkJZplxn/XW6Evxo/zh9dhNj4iBINi7uhtZE7uxtYj6VHbMRY227UBLQopxr vA+Qqrv3Kx/rysxpuwoe3MAfliXIlLQ+qKMwn1RbYV3rSp5I6GX8LJeEbemvWxEFsGOd4 iajoVk4pIvoWZqAgDZ+Skbr00pUABxkVdanSuRNORHAvRrIS1oY4lfpbjpBi0rHV2bDVU O3zvOHg+Of8GnKKA0DkstmKADy+2K5AlJ1nHbIGt9En4gwieFYWQFuW6hhyZnVoYCZqxy yndND+UVWxKErLIT0TnO99MyY0U8xTxuIhLcOwopzfXkkLHxjMO+G+xtxmc6loPnrEg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=bs3ewZ+v; 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 7644B606A31C for ; Tue, 10 Nov 2026 22:59:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=bs3ewZ+v Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61A531F0093C; Tue, 10 Nov 2026 22:59:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794351597; bh=bFIpRPx2YZGBGUB7lpvwu3PR8rwLsePjl+Y2HF5Tgp0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bs3ewZ+vb2gZEPEjHAIm0RHvIO0b+25N6FAerZ+uSAT8FNsK1SYgBEOPezjGJC/3r 6ECvdB/VJfoiVRg6mpycstloZ36ATKXG2yUhhZPwX7g7IAER6aLa0PY80lsnTkFYXj 8CwJBlR/w6fqxlyCxZoeRduvrtsyJsrPwIO3qYhZQk70hxwxW6fWVM9phpAWcfJ+1p htjMXu2ztl4HXJEsvkt1GyyyzrxTlCVA2hq3+rlIZ1XYv+QGX9dTiluQ6kbH+r++mh NkPr7ptH9DdvNB28zoF9/KLpjj9oe2F6OK4K3mUSmD81wS7fsSb+Lo4rM3z0p/l7Ij SYY5DDEepeVcA== From: Sasha Levin To: stable@vger.kernel.org Cc: Xiang Mei , co+ecaada42f806f629@bugs.sh, Alex Markuze , Ilya Dryomov , Sasha Levin Subject: [PATCH 5.15.y] ceph: fix integer overflow in the snap trace bounds check Date: Tue, 10 Nov 2026 17:59:55 -0500 Message-ID: <20261110225923.4141850-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107061207-failed-5.15-b3bf89767e3c@kernel.org> References: <20261107061207-failed-5.15-b3bf89767e3c@kernel.org> 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 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 [ sashal: Adjusted snaps_len declaration placement to account for missing client and ret declarations. ] 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 74a1fc919c6be..ce1f489e00e84 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -710,6 +710,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm; struct ceph_snap_realm *first_realm = NULL; struct ceph_snap_realm *realm_to_rebuild = NULL; + size_t snaps_len; int rebuild_snapcs; int err = -ENOMEM; LIST_HEAD(dirty_realms); @@ -723,8 +724,10 @@ 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