Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.9 23/26] cifs: read overflow in is_valid_oplock_break() | Date | Mon, 1 Oct 2018 00:40:43 +0000 |
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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> --- fs/cifs/misc.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 323d8e34abde..50559a80acf8 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -406,9 +406,17 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv) (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", -- 2.17.1
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