On Fri, Dec 10, 2010 at 3:13 PM, Jeff Layton <[email protected]> wrote:
> On Fri, 10 Dec 2010 10:30:47 -0600
> [email protected] wrote:
>
>> From: Shirish Pargaonkar <[email protected]>
>>
>>
>> Indicate to the server a capability of NTLM2 session security (NTLM2 Key)
>> during ntlmssp protocol exchange in one of the bits of the flags field.
>> If server supports this capability, send NTLM2 key even if signing is not
>> required on the server.
>>
>> If the server requires signing, the session keys exchanged for NTLMv2
>> and NTLM2 session security in auth packet of the nlmssp exchange are same.
>>
>> Send the same flags in authenticate message (type 3) that client sent in
>> negotiate message (type 1).
>>
>> Remove function setup_ntlmssp_neg_req() and allocate zero'ed buffers
>> to prepare ntlmssp negotiate and authenticat requests.
>>
>>
>> Reported-and-Tested-by: Robbert Kouprie <[email protected]>
>> Signed-off-by: Shirish Pargaonkar <[email protected]>
>> ---
>> fs/cifs/sess.c | 46 +++++++++++++++++++++++++---------------------
>> 1 files changed, 25 insertions(+), 21 deletions(-)
>>
>> diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
>> index 7b01d3f..56e945a 100644
>> --- a/fs/cifs/sess.c
>> +++ b/fs/cifs/sess.c
>> @@ -425,7 +425,7 @@ static int decode_ntlmssp_challenge(char *bcc_ptr, int
>> blob_len,
>>
>> /* We do not malloc the blob, it is passed in pbuffer, because
>> it is fixed size, and small, making this approach cleaner */
>> -static void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
>> +static void build_ntlmssp_negotiate_blob(char *pbuffer,
>> struct cifsSesInfo *ses)
>> {
>> NEGOTIATE_MESSAGE *sec_blob = (NEGOTIATE_MESSAGE *)pbuffer;
>> @@ -437,7 +437,7 @@ static void build_ntlmssp_negotiate_blob(unsigned char
>> *pbuffer,
>> /* BB is NTLMV2 session security format easier to use here? */
>> flags = NTLMSSP_NEGOTIATE_56 | NTLMSSP_REQUEST_TARGET |
>> NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
>> - NTLMSSP_NEGOTIATE_NTLM;
>> + NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC;
>> if (ses->server->secMode &
>> (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
>> flags |= NTLMSSP_NEGOTIATE_SIGN;
>> @@ -446,7 +446,7 @@ static void build_ntlmssp_negotiate_blob(unsigned char
>> *pbuffer,
>> NTLMSSP_NEGOTIATE_EXTENDED_SEC;
>> }
>>
>> - sec_blob->NegotiateFlags |= cpu_to_le32(flags);
>> + sec_blob->NegotiateFlags = cpu_to_le32(flags);
>>
>> sec_blob->WorkstationName.BufferOffset = 0;
>> sec_blob->WorkstationName.Length = 0;
>> @@ -477,7 +477,7 @@ static int build_ntlmssp_auth_blob(unsigned char
>> *pbuffer,
>> flags = NTLMSSP_NEGOTIATE_56 |
>> NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_TARGET_INFO |
>> NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
>> - NTLMSSP_NEGOTIATE_NTLM;
>> + NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC;
>> if (ses->server->secMode &
>> (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
>> flags |= NTLMSSP_NEGOTIATE_SIGN;
>> @@ -485,7 +485,7 @@ static int build_ntlmssp_auth_blob(unsigned char
>> *pbuffer,
>> flags |= NTLMSSP_NEGOTIATE_ALWAYS_SIGN;
>>
>> tmp = pbuffer + sizeof(AUTHENTICATE_MESSAGE);
>> - sec_blob->NegotiateFlags |= cpu_to_le32(flags);
>> + sec_blob->NegotiateFlags = cpu_to_le32(flags);
>>
>> sec_blob->LmChallengeResponse.BufferOffset =
>> cpu_to_le32(sizeof(AUTHENTICATE_MESSAGE));
>> @@ -544,8 +544,9 @@ static int build_ntlmssp_auth_blob(unsigned char
>> *pbuffer,
>> sec_blob->WorkstationName.MaximumLength = 0;
>> tmp += 2;
>>
>> - if ((ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) &&
>> - !calc_seckey(ses)) {
>> + if (((ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_KEY_XCH) ||
>> + (ses->ntlmssp->server_flags & NTLMSSP_NEGOTIATE_EXTENDED_SEC))
>> + && !calc_seckey(ses)) {
>> memcpy(tmp, ses->ntlmssp->ciphertext, CIFS_CPHTXT_SIZE);
>> sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> sec_blob->SessionKey.Length = cpu_to_le16(CIFS_CPHTXT_SIZE);
>> @@ -562,16 +563,6 @@ setup_ntlmv2_ret:
>> *buflen = tmp - pbuffer;
>> return rc;
>> }
>> -
>> -
>> -static void setup_ntlmssp_neg_req(SESSION_SETUP_ANDX *pSMB,
>> - struct cifsSesInfo *ses)
>> -{
>> - build_ntlmssp_negotiate_blob(&pSMB->req.SecurityBlob[0], ses);
>> - pSMB->req.SecurityBlobLength = cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));
>> -
>> - return;
>> -}
> ^^^^^
> I like that you removed the above function. It was useless indirection.
>
>> #endif
>>
>> int
>> @@ -595,6 +586,7 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
>> __le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
>> u16 blob_len;
>> char *ntlmsspblob = NULL;
>> + char *ntlmsspnblob = NULL;
>>
>> if (ses == NULL)
>> return -EINVAL;
>> @@ -828,16 +820,26 @@ ssetup_ntlmssp_authenticate:
>> capabilities |= CAP_EXTENDED_SECURITY;
>> pSMB->req.Capabilities |= cpu_to_le32(capabilities);
>> if (phase == NtLmNegotiate) {
>> - setup_ntlmssp_neg_req(pSMB, ses);
>> + ntlmsspnblob = kzalloc(
>> + sizeof(struct _NEGOTIATE_MESSAGE),
>> + GFP_KERNEL);
>> + if (!ntlmsspnblob) {
>> + cERROR(1, "Can't allocate NTLMSSPN");
>> + rc = -ENOMEM;
>> + goto ssetup_exit;
>> + }
>> + build_ntlmssp_negotiate_blob(ntlmsspnblob,
>> ses);
>
> Why did you decide to allocate a new buffer here? Was the SecurityBlob
> not big enough? If not, then I think it would make more sense to just
> memset the existing buffer to 0.
No the buffer allocated by small_smb_init is sufficient to hold the
ntlmssp negotiate request. I do not need to allocate a new buffer.
And header_assemble memsets that buffer to 0, so no need to redo it again.
So only ntlmsspblob needs to be kzalloc'ed.
>
>> iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
>> - iov[1].iov_base = &pSMB->req.SecurityBlob[0];
>> + iov[1].iov_base = ntlmsspnblob;
>> + pSMB->req.SecurityBlobLength =
>> + cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));
>> } else if (phase == NtLmAuthenticate) {
>> - /* 5 is an empirical value, large enought to
>> + /* 5 is an empirical value, large enough to
>> * hold authenticate message, max 10 of
>> * av paris, doamin,user,workstation mames,
>> * flags etc..
>> */
>> - ntlmsspblob = kmalloc(
>> + ntlmsspblob = kzalloc(
>> 5*sizeof(struct _AUTHENTICATE_MESSAGE),
>> GFP_KERNEL);
>> if (!ntlmsspblob) {
>> @@ -960,6 +962,8 @@ ssetup_exit:
>> key_put(spnego_key);
>> }
>> kfree(str_area);
>> + kfree(ntlmsspnblob);
>> + ntlmsspnblob = NULL;
>
> If we did decide that we needed a new buffer for this, I don't think we
> need a new pointer on the stack for it. ntlmsspblob would suffice in
> that case.
>
>> kfree(ntlmsspblob);
>> ntlmsspblob = NULL;
>> if (resp_buf_type == CIFS_SMALL_BUFFER) {
>
> --
> Jeff Layton <[email protected]>
>
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