From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56132 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730063AbeIXSU0 (ORCPT ); Mon, 24 Sep 2018 14:20:26 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dr Silvio Cesare of InfoSect , Ronnie Sahlberg , Aurelien Aptel , Dan Carpenter , Steve French Subject: [PATCH 4.14 101/173] cifs: prevent integer overflow in nxt_dir_entry() Date: Mon, 24 Sep 2018 13:52:15 +0200 Message-Id: <20180924113123.493910670@linuxfoundation.org> In-Reply-To: <20180924113114.334025954@linuxfoundation.org> References: <20180924113114.334025954@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter commit 8ad8aa353524d89fa2e09522f3078166ff78ec42 upstream. The "old_entry + le32_to_cpu(pDirInfo->NextEntryOffset)" can wrap around so I have added a check for integer overflow. Reported-by: Dr Silvio Cesare of InfoSect Reviewed-by: Ronnie Sahlberg Reviewed-by: Aurelien Aptel Signed-off-by: Dan Carpenter Signed-off-by: Steve French CC: Stable Signed-off-by: Greg Kroah-Hartman --- fs/cifs/readdir.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -376,8 +376,15 @@ static char *nxt_dir_entry(char *old_ent new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) + pfData->FileNameLength; - } else - new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset); + } else { + u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset); + + if (old_entry + next_offset < old_entry) { + cifs_dbg(VFS, "invalid offset %u\n", next_offset); + return NULL; + } + new_entry = old_entry + next_offset; + } cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry); /* validate that new_entry is not past end of SMB */ if (new_entry >= end_of_smb) {