| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 75/94] cifs: read overflow in is_valid_oplock_break() | Date | Mon, 8 Oct 2018 20:31:56 +0200 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter <dan.carpenter@oracle.com>
[ Upstream commit 097f5863b1a0c9901f180bbd56ae7d630655faaa ]
We need to verify that the "data_offset" is within bounds.
Reported-by: Dr Silvio Cesare of InfoSect <silvio.cesare@gmail.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/cifs/misc.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -398,9 +398,17 @@ is_valid_oplock_break(char *buffer, stru (struct smb_com_transaction_change_notify_rsp *)buf; struct file_notify_information *pnotify; __u32 data_offset = 0; + size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length); + if (get_bcc(buf) > sizeof(struct file_notify_information)) { data_offset = le32_to_cpu(pSMBr->DataOffset); + if (data_offset > + len - sizeof(struct file_notify_information)) { + cifs_dbg(FYI, "invalid data_offset %u\n", + data_offset); + return true; + } pnotify = (struct file_notify_information *) ((char *)&pSMBr->hdr.Protocol + data_offset); cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
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