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 90581C7EE23 for ; Tue, 30 May 2023 12:59:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232278AbjE3M7i (ORCPT ); Tue, 30 May 2023 08:59:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232172AbjE3M7h (ORCPT ); Tue, 30 May 2023 08:59:37 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C726F9 for ; Tue, 30 May 2023 05:59:13 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id d2e1a72fcca58-64d341bdedcso3176144b3a.3 for ; Tue, 30 May 2023 05:59:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685451492; x=1688043492; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=FnNMAiSYagBoQy7G3Rszl8N/LirJbUlAbAH4gMgMbNs=; b=UjQnPs1Wc8cPWnQdlF+G7v9J1uAoKJXpcnrycrdyBA9AN+wcJR/qXE/Uj4SQpirCAl W+ua+h2ZypiQUM/6+XwtmHeI20S469A2ndoIzvVkHWGDJAjtmLJBQ4Ya2KoFItABt+zZ tk4w2GbYnNbU1ir7le5xoK+hpxZ2jKXj/KXuk+MJxurxn98Noq7lBAw0WMA4RMjks4qo QtG+0JgAhi7Aj7LDcRLaj9T+7YIs78vsjnFPMwkmZAnIR4L8ktlqNTWXTeHLHNa3v3UR clDj694FpkgKyHa3euY07XwrSNG5jed5Gep8NZdwUGINpRvQb24jBFwxnKB07W9FLpdG gmVA== X-Gm-Message-State: AC+VfDwU42GzogPkx/wAeDXHwH7rKiLD4h2zT6KprBZMvvzEhGzVlalD Y5yCfkVCDjG7vggWKetuc9nNn2xKgJ0= X-Google-Smtp-Source: ACHHUZ6LdYPbPOKcniKBCMf0cu3pkagQ4QoV+ZsfN6/fq30WPG1YWjjDVKFyLrMgCJ05ECqwoVotcw== X-Received: by 2002:a05:6a00:a0b:b0:64d:42cb:42af with SMTP id p11-20020a056a000a0b00b0064d42cb42afmr2762577pfh.4.1685451492564; Tue, 30 May 2023 05:58:12 -0700 (PDT) Received: from localhost.localdomain ([211.49.23.9]) by smtp.gmail.com with ESMTPSA id c17-20020aa78c11000000b0063afb08afeesm1605007pfd.67.2023.05.30.05.58.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 May 2023 05:58:12 -0700 (PDT) From: Namjae Jeon To: linux-cifs@vger.kernel.org Cc: smfrench@gmail.com, senozhatsky@chromium.org, tom@talpey.com, atteh.mailbox@gmail.com, Namjae Jeon , Chih-Yen Chang Subject: [PATCH] ksmbd: fix out-of-bound read in deassemble_neg_contexts() Date: Tue, 30 May 2023 21:57:54 +0900 Message-Id: <20230530125757.12910-1-linkinjeon@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org The check in the beginning is `clen + sizeof(struct smb2_neg_context) <= len_of_ctxts`, but in the end of loop, `len_of_ctxts` will subtract `((clen + 7) & ~0x7) + sizeof(struct smb2_neg_context)`, which causes integer underflow when clen does the 8 alignment. We should use `(clen + 7) & ~0x7` in the check to avoid underflow from happening. Then there are some variables that need to be declared unsigned instead of signed. [ 11.671070] BUG: KASAN: slab-out-of-bounds in smb2_handle_negotiate+0x799/0x1610 [ 11.671533] Read of size 2 at addr ffff888005e86cf2 by task kworker/0:0/7 ... [ 11.673383] Call Trace: [ 11.673541] [ 11.673679] dump_stack_lvl+0x33/0x50 [ 11.673913] print_report+0xcc/0x620 [ 11.674671] kasan_report+0xae/0xe0 [ 11.675171] kasan_check_range+0x35/0x1b0 [ 11.675412] smb2_handle_negotiate+0x799/0x1610 [ 11.676217] ksmbd_smb_negotiate_common+0x526/0x770 [ 11.676795] handle_ksmbd_work+0x274/0x810 ... Signed-off-by: Chih-Yen Chang Tested-by: Chih-Yen Chang Signed-off-by: Namjae Jeon --- fs/smb/server/smb2pdu.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 7a81541de602..25c0ba04c59d 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -963,13 +963,13 @@ static void decode_sign_cap_ctxt(struct ksmbd_conn *conn, static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn, struct smb2_negotiate_req *req, - int len_of_smb) + unsigned int len_of_smb) { /* +4 is to account for the RFC1001 len field */ struct smb2_neg_context *pctx = (struct smb2_neg_context *)req; int i = 0, len_of_ctxts; - int offset = le32_to_cpu(req->NegotiateContextOffset); - int neg_ctxt_cnt = le16_to_cpu(req->NegotiateContextCount); + unsigned int offset = le32_to_cpu(req->NegotiateContextOffset); + unsigned int neg_ctxt_cnt = le16_to_cpu(req->NegotiateContextCount); __le32 status = STATUS_INVALID_PARAMETER; ksmbd_debug(SMB, "decoding %d negotiate contexts\n", neg_ctxt_cnt); @@ -983,7 +983,7 @@ static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn, while (i++ < neg_ctxt_cnt) { int clen, ctxt_len; - if (len_of_ctxts < sizeof(struct smb2_neg_context)) + if (len_of_ctxts < (int)sizeof(struct smb2_neg_context)) break; pctx = (struct smb2_neg_context *)((char *)pctx + offset); @@ -1038,9 +1038,8 @@ static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn, } /* offsets must be 8 byte aligned */ - clen = (clen + 7) & ~0x7; - offset = clen + sizeof(struct smb2_neg_context); - len_of_ctxts -= clen + sizeof(struct smb2_neg_context); + offset = (ctxt_len + 7) & ~0x7; + len_of_ctxts -= offset; } return status; } -- 2.25.1