From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DBFBC2BB41 for ; Tue, 16 Aug 2022 06:37:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230014AbiHPGh5 (ORCPT ); Tue, 16 Aug 2022 02:37:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229772AbiHPGhj (ORCPT ); Tue, 16 Aug 2022 02:37:39 -0400 Received: from lgeamrelo11.lge.com (lgeamrelo13.lge.com [156.147.23.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F04BAE3415 for ; Mon, 15 Aug 2022 18:15:46 -0700 (PDT) Received: from unknown (HELO lgeamrelo04.lge.com) (156.147.1.127) by 156.147.23.53 with ESMTP; 16 Aug 2022 09:45:44 +0900 X-Original-SENDERIP: 156.147.1.127 X-Original-MAILFROM: hyc.lee@gmail.com Received: from unknown (HELO localhost.localdomain) (10.177.245.62) by 156.147.1.127 with ESMTP; 16 Aug 2022 09:45:44 +0900 X-Original-SENDERIP: 10.177.245.62 X-Original-MAILFROM: hyc.lee@gmail.com From: Hyunchul Lee To: stable@vger.kernel.org Cc: Namjae Jeon , Steve French , Greg Kroah-Hartman , Steve French Subject: [PATCH 5.15.y 1/2] ksmbd: prevent out of bound read for SMB2_WRITE Date: Tue, 16 Aug 2022 09:44:30 +0900 Message-Id: <20220816004431.30133-1-hyc.lee@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit ac60778b87e45576d7bfdbd6f53df902654e6f09 ] OOB read memory can be written to a file, if DataOffset is 0 and Length is too large in SMB2_WRITE request of compound request. To prevent this, when checking the length of the data area of SMB2_WRITE in smb2_get_data_area_len(), let the minimum of DataOffset be the size of SMB2 header + the size of SMB2_WRITE header. This bug can lead an oops looking something like: [ 798.008715] BUG: KASAN: slab-out-of-bounds in copy_page_from_iter_atomic+0xd3d/0x14b0 [ 798.008724] Read of size 252 at addr ffff88800f863e90 by task kworker/0:2/2859 ... [ 798.008754] Call Trace: [ 798.008756] [ 798.008759] dump_stack_lvl+0x49/0x5f [ 798.008764] print_report.cold+0x5e/0x5cf [ 798.008768] ? __filemap_get_folio+0x285/0x6d0 [ 798.008774] ? copy_page_from_iter_atomic+0xd3d/0x14b0 [ 798.008777] kasan_report+0xaa/0x120 [ 798.008781] ? copy_page_from_iter_atomic+0xd3d/0x14b0 [ 798.008784] kasan_check_range+0x100/0x1e0 [ 798.008788] memcpy+0x24/0x60 [ 798.008792] copy_page_from_iter_atomic+0xd3d/0x14b0 [ 798.008795] ? pagecache_get_page+0x53/0x160 [ 798.008799] ? iov_iter_get_pages_alloc+0x1590/0x1590 [ 798.008803] ? ext4_write_begin+0xfc0/0xfc0 [ 798.008807] ? current_time+0x72/0x210 [ 798.008811] generic_perform_write+0x2c8/0x530 [ 798.008816] ? filemap_fdatawrite_wbc+0x180/0x180 [ 798.008820] ? down_write+0xb4/0x120 [ 798.008824] ? down_write_killable+0x130/0x130 [ 798.008829] ext4_buffered_write_iter+0x137/0x2c0 [ 798.008833] ext4_file_write_iter+0x40b/0x1490 [ 798.008837] ? __fsnotify_parent+0x275/0xb20 [ 798.008842] ? __fsnotify_update_child_dentry_flags+0x2c0/0x2c0 [ 798.008846] ? ext4_buffered_write_iter+0x2c0/0x2c0 [ 798.008851] __kernel_write+0x3a1/0xa70 [ 798.008855] ? __x64_sys_preadv2+0x160/0x160 [ 798.008860] ? security_file_permission+0x4a/0xa0 [ 798.008865] kernel_write+0xbb/0x360 [ 798.008869] ksmbd_vfs_write+0x27e/0xb90 [ksmbd] [ 798.008881] ? ksmbd_vfs_read+0x830/0x830 [ksmbd] [ 798.008892] ? _raw_read_unlock+0x2a/0x50 [ 798.008896] smb2_write+0xb45/0x14e0 [ksmbd] [ 798.008909] ? __kasan_check_write+0x14/0x20 [ 798.008912] ? _raw_spin_lock_bh+0xd0/0xe0 [ 798.008916] ? smb2_read+0x15e0/0x15e0 [ksmbd] [ 798.008927] ? memcpy+0x4e/0x60 [ 798.008931] ? _raw_spin_unlock+0x19/0x30 [ 798.008934] ? ksmbd_smb2_check_message+0x16af/0x2350 [ksmbd] [ 798.008946] ? _raw_spin_lock_bh+0xe0/0xe0 [ 798.008950] handle_ksmbd_work+0x30e/0x1020 [ksmbd] [ 798.008962] process_one_work+0x778/0x11c0 [ 798.008966] ? _raw_spin_lock_irq+0x8e/0xe0 [ 798.008970] worker_thread+0x544/0x1180 [ 798.008973] ? __cpuidle_text_end+0x4/0x4 [ 798.008977] kthread+0x282/0x320 [ 798.008982] ? process_one_work+0x11c0/0x11c0 [ 798.008985] ? kthread_complete_and_exit+0x30/0x30 [ 798.008989] ret_from_fork+0x1f/0x30 [ 798.008995] Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-17817 Signed-off-by: Hyunchul Lee Acked-by: Namjae Jeon Signed-off-by: Steve French --- fs/ksmbd/smb2misc.c | 7 +++++-- fs/ksmbd/smb2pdu.c | 6 ++---- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c index 66b24b480ebf..b47be71be4c8 100644 --- a/fs/ksmbd/smb2misc.c +++ b/fs/ksmbd/smb2misc.c @@ -132,8 +132,11 @@ static int smb2_get_data_area_len(unsigned int *off, unsigned int *len, *len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength); break; case SMB2_WRITE: - if (((struct smb2_write_req *)hdr)->DataOffset) { - *off = le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset); + if (((struct smb2_write_req *)hdr)->DataOffset || + ((struct smb2_write_req *)hdr)->Length) { + *off = max_t(unsigned int, + le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset), + offsetof(struct smb2_write_req, Buffer) - 4); *len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length); break; } diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index 53f5db40b96e..06552a67a810 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -6471,10 +6471,8 @@ int smb2_write(struct ksmbd_work *work) (offsetof(struct smb2_write_req, Buffer) - 4)) { data_buf = (char *)&req->Buffer[0]; } else { - if ((u64)le16_to_cpu(req->DataOffset) + length > get_rfc1002_len(req)) { - pr_err("invalid write data offset %u, smb_len %u\n", - le16_to_cpu(req->DataOffset), - get_rfc1002_len(req)); + if (le16_to_cpu(req->DataOffset) < + offsetof(struct smb2_write_req, Buffer)) { err = -EINVAL; goto out; } -- 2.17.1