On Fri, Sep 17, 2010 at 9:19 AM, Jeff Layton <jlayton@xxxxxxxxx> wrote:
> On Thu, 16 Sep 2010 00:47:03 -0500
> shirishpargaonkar@xxxxxxxxx wrote:
>
>> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>>
>>
>> Attribue Value (AV) pairs or Target Info (TI) pairs are part of
>> ntlmv2 authentication.
>> Structure ntlmv2_resp had only definition for two av pairs.
>> So removed it, and now allocation of av pairs is dynamic.
>> For servers like Windows 7/2008, av pairs sent by server in
>> challege packet (type 2 in the ntlmssp exchange/negotiation) can
>> vary.
>>
>> Server sends them during ntlmssp negotiation. So when ntlmssp is used
>> as an authentication mechanism, type 2 challenge packet from server
>> has this information. Pluck it and use the entire blob for
>> authenticaiton purpose. If user has not specified, extract
>> (netbios) domain name from the av pairs which is used to calculate
>> ntlmv2 hash. Servers like Windows 7 are particular about the AV pair
>> blob.
>>
>> Servers like Windows 2003, are not very strict about the contents
>> of av pair blob used during ntlmv2 authentication.
>> So when security mechanism such as ntlmv2 is used (not ntlmv2 in ntlmssp),
>> there is no negotiation and so genereate a minimal blob that gets
>> used in ntlmv2 authentication as well as gets sent.
>>
>> Fields tilen, tilbob, and tidomain are session specific.
>> AV pair values are defined.
>> tidomain is used to figure out whether domainName field of smb session
>> was allocated during ntlmssp exchange. If it was, then it gets freed
>> once (netbios) domain name is used as a part of ntlmv2 hash calculation
>> and then as a part of ntlmv2 ntlmssp response.
>>
>> To calculate ntlmv2 response we need ti/av pair blob.
>>
>> For sec mech like ntlmssp, the blob is plucked from type 2 response from
>> the server. From this blob, netbios name of the domain is retrieved,
>> if user has not already provided, to be included in the Target String
>> as part of ntlmv2 hash calculations.
>>
>> For sec mech like ntlmv2, create a minimal, two av pair blob.
>>
>> The allocated blob is freed in case of error. In case there is no error,
>> this blob is used in calculating ntlmv2 response (in CalcNTLMv2_response)
>> and is also copied on the response to the server, and then freed.
>>
>> The type 3 ntlmssp response is prepared on a buffer,
>> 5 * sizeof of struct _AUTHENTICATE_MESSAGE, an empirical value large
>> enough to hold _AUTHENTICATE_MESSAGE plus a blob with max possible
>> 10 values as part of ntlmv2 response and lmv2 keys and domain, user,
>> workstation names etc.
>>
>> Also, kerberos gets selected as a default mechanism if server supports it,
>> over the other security mechanisms.
>>
>>
>> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>>
>>
>> ---
>> fs/cifs/cifsencrypt.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++--
>> fs/cifs/cifsglob.h | 3 +
>> fs/cifs/cifspdu.h | 1 -
>> fs/cifs/cifsproto.h | 2 +-
>> fs/cifs/cifssmb.c | 16 ++++---
>> fs/cifs/connect.c | 3 +
>> fs/cifs/ntlmssp.h | 15 ++++++
>> fs/cifs/sess.c | 127 ++++++++++++++++++++++++++++++++++---------------
>> 8 files changed, 241 insertions(+), 53 deletions(-)
>>
>> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
>> index eed70ca..6cf58c0 100644
>> --- a/fs/cifs/cifsencrypt.c
>> +++ b/fs/cifs/cifsencrypt.c
>> @@ -27,6 +27,7 @@
>> #include "md5.h"
>> #include "cifs_unicode.h"
>> #include "cifsproto.h"
>> +#include "ntlmssp.h"
>> #include <linux/ctype.h>
>> #include <linux/random.h>
>>
>> @@ -262,6 +263,88 @@ void calc_lanman_hash(const char *password, const char *cryptkey, bool encrypt,
>> }
>> #endif /* CIFS_WEAK_PW_HASH */
>>
>> +/* This is just a filler for ntlmv2 type of security mechanisms.
>> + * Older servers are not very particular about the contents of av pairs
>> + * in the blob and for sec mechs like ntlmv2, there is no negotiation
>> + * as in ntlmssp, so unless domain and server netbios and dns names
>> + * are specified, there is no way to obtain name. In case of ntlmssp,
>> + * server provides that info in type 2 challenge packet
>> + */
>> +static int
>> +build_avpair_blob(struct cifsSesInfo *ses)
>> +{
>> + struct ntlmssp2_name *attrptr;
>> +
>> + ses->tilen = 2 * sizeof(struct ntlmssp2_name);
>> + ses->tiblob = kzalloc(ses->tilen, GFP_KERNEL);
>> + if (!ses->tiblob) {
>> + ses->tilen = 0;
>> + cERROR(1, "Challenge target info allocation failure");
>> + return -ENOMEM;
>> + }
>> + attrptr = (struct ntlmssp2_name *) ses->tiblob;
>> + attrptr->type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
>> +
>> + return 0;
>> +}
>> +
>> +/* Server has provided av pairs/target info in the type 2 challenge
>> + * packet and we have plucked it and stored within smb session.
>> + * We parse that blob here to find netbios domain name to be used
>> + * as part of ntlmv2 authentication (in Target String), if not already
>> + * specified on the command line.
>> + * If this function returns without any error but without fetching
>> + * domain name, authentication may fail against some server but
>> + * may not fail against other (those who are not very particular
>> + * about target string i.e. for some, just user name might suffice.
>> + */
>> +static int
>> +find_domain_name(struct cifsSesInfo *ses)
>> +{
>> + unsigned int attrsize;
>> + unsigned int type;
>> + unsigned int onesize = sizeof(struct ntlmssp2_name);
>> + unsigned char *blobptr;
>> + unsigned char *blobend;
>> + struct ntlmssp2_name *attrptr;
>> +
>> + if (!ses->tilen || !ses->tiblob)
>> + return 0;
>> +
>> + blobptr = ses->tiblob;
>> + blobend = ses->tiblob + ses->tilen;
>> +
>> + while (blobptr + onesize < blobend) {
>> + attrptr = (struct ntlmssp2_name *) blobptr;
>> + type = le16_to_cpu(attrptr->type);
>> + if (type == NTLMSSP_AV_EOL)
>> + break;
>> + blobptr += 2; /* advance attr type */
>> + attrsize = le16_to_cpu(attrptr->length);
>> + blobptr += 2; /* advance attr size */
>> + if (blobptr + attrsize > blobend)
>> + break;
>> + if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
>> + if (!attrsize)
>> + break;
>> + if (!ses->domainName) {
>> + ses->domainName =
>> + kmalloc(attrsize + 1, GFP_KERNEL);
>> + if (!ses->domainName)
>> + return -ENOMEM;
>> + cifs_from_ucs2(ses->domainName,
>> + (__le16 *)blobptr, attrsize, attrsize,
>> + load_nls_default(), false);
>> + ses->tidomain = true;
>> + break;
>> + }
>> + }
>> + blobptr += attrsize; /* advance attr value */
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
>> const struct nls_table *nls_cp)
>> {
>> @@ -321,7 +404,8 @@ calc_exit_2:
>> return rc;
>> }
>>
>> -void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
>> +int
>> +setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
>> const struct nls_table *nls_cp)
>> {
>> int rc;
>> @@ -333,15 +417,29 @@ void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
>> buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
>> get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
>> buf->reserved2 = 0;
>> - buf->names[0].type = cpu_to_le16(NTLMSSP_DOMAIN_TYPE);
>> - buf->names[0].length = 0;
>> - buf->names[1].type = 0;
>> - buf->names[1].length = 0;
>> +
>> + if (ses->server->secType == RawNTLMSSP) {
>> + if (!ses->domainName) {
>> + rc = find_domain_name(ses);
>> + if (rc) {
>> + cERROR(1, "error %d finding domain name", rc);
>> + goto setup_ntlmv2_rsp_ret;
>> + }
>> + }
>> + } else {
>> + rc = build_avpair_blob(ses);
>> + if (rc) {
>> + cERROR(1, "error %d building av pair blob", rc);
>> + return rc;
>> + }
>> + }
>>
>> /* calculate buf->ntlmv2_hash */
>> rc = calc_ntlmv2_hash(ses, nls_cp);
>> - if (rc)
>> + if (rc) {
>> cERROR(1, "could not get v2 hash rc %d", rc);
>> + goto setup_ntlmv2_rsp_ret;
>> + }
>> CalcNTLMv2_response(ses, resp_buf);
>>
>> /* now calculate the MAC key for NTLMv2 */
>> @@ -352,6 +450,20 @@ void setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
>> memcpy(&ses->server->session_key.data.ntlmv2.resp, resp_buf,
>> sizeof(struct ntlmv2_resp));
>> ses->server->session_key.len = 16 + sizeof(struct ntlmv2_resp);
>> +
>> + return 0;
>> +
>> +setup_ntlmv2_rsp_ret:
>> + if (ses->tidomain) {
>> + kfree(ses->domainName);
>> + ses->domainName = NULL;
>> + ses->tidomain = false;
> ^^^^^
> I don't understand the need for the tidomain flag. IIUC, we have two
> ways to get the domainName:
>
> 1) user supplies it via mount option
>
> 2) server supplies it via NTLMSSP AV pairs
>
> In the first case, this gets allocated at mount time and then freed in
> sesInfoFree. Why is it important to free it here? Why not just hold
> onto the domainName string here and let it be freed in sesInfoFree?
Jeff, only if the domainName was malloced in case user did not supply
it, do we free it.
I am not aware of any multidomain servers but if there
is such a set up, and if domain name is not enough to distinguish
a different session, can a tree connect come with different user supplied
domain name?
I am probably fetching it too far but I will remove that code and if we run
into such a thing, can always add back. And I was not thinking of this case
when I added that code, but added it with the consideration that what was
malloc'ed during session setup, should be freed.
>
>> + }
>> + kfree(ses->tiblob);
>> + ses->tiblob = NULL;
>> + ses->tilen = 0;
>> +
>> + return rc;
>> }
>>
>> void CalcNTLMv2_response(const struct cifsSesInfo *ses,
>> @@ -365,6 +477,9 @@ void CalcNTLMv2_response(const struct cifsSesInfo *ses,
>> hmac_md5_update(v2_session_response+8,
>> sizeof(struct ntlmv2_resp) - 8, &context);
>>
>> + if (ses->tilen)
>> + hmac_md5_update(ses->tiblob, ses->tilen, &context);
>> +
>> hmac_md5_final(v2_session_response, &context);
>> /* cifs_dump_mem("v2_sess_rsp: ", v2_session_response, 32); */
>> }
>> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>> index 14dfa9a..d6dbe18 100644
>> --- a/fs/cifs/cifsglob.h
>> +++ b/fs/cifs/cifsglob.h
>> @@ -222,6 +222,9 @@ struct cifsSesInfo {
>> char userName[MAX_USERNAME_SIZE + 1];
>> char *domainName;
>> char *password;
>> + unsigned int tilen; /* length of the target info blob */
>> + unsigned char *tiblob; /* target info blob in challenge response */
>> + bool tidomain; /* domain name was kmalloc'ed, free it */
>> bool need_reconnect:1; /* connection reset, uid now invalid */
>> };
>> /* no more than one of the following three session flags may be set */
>> diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
>> index 14d036d..b0f4b56 100644
>> --- a/fs/cifs/cifspdu.h
>> +++ b/fs/cifs/cifspdu.h
>> @@ -663,7 +663,6 @@ struct ntlmv2_resp {
>> __le64 time;
>> __u64 client_chal; /* random */
>> __u32 reserved2;
>> - struct ntlmssp2_name names[2];
>> /* array of name entries could follow ending in minimum 4 byte struct */
>> } __attribute__((packed));
>>
>> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
>> index 3f4fa81..c155479 100644
>> --- a/fs/cifs/cifsproto.h
>> +++ b/fs/cifs/cifsproto.h
>> @@ -367,7 +367,7 @@ extern int cifs_verify_signature(struct smb_hdr *,
>> extern int cifs_calculate_session_key(struct session_key *key, const char *rn,
>> const char *pass);
>> extern void CalcNTLMv2_response(const struct cifsSesInfo *, char *);
>> -extern void setup_ntlmv2_rsp(struct cifsSesInfo *, char *,
>> +extern int setup_ntlmv2_rsp(struct cifsSesInfo *, char *,
>> const struct nls_table *);
>> #ifdef CONFIG_CIFS_WEAK_PW_HASH
>> extern void calc_lanman_hash(const char *password, const char *cryptkey,
>> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
>> index c65c341..13c854e 100644
>> --- a/fs/cifs/cifssmb.c
>> +++ b/fs/cifs/cifssmb.c
>> @@ -603,13 +603,15 @@ CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
>> rc = 0;
>> else
>> rc = -EINVAL;
>> -
>> - if (server->sec_kerberos || server->sec_mskerberos)
>> - server->secType = Kerberos;
>> - else if (server->sec_ntlmssp)
>> - server->secType = RawNTLMSSP;
>> - else
>> - rc = -EOPNOTSUPP;
>> + if (server->secType == Kerberos) {
>> + if (!server->sec_kerberos &&
>> + !server->sec_mskerberos)
>> + rc = -EOPNOTSUPP;
>> + } else if (server->secType == RawNTLMSSP) {
>> + if (!server->sec_ntlmssp)
>> + rc = -EOPNOTSUPP;
>> + } else
>> + rc = -EOPNOTSUPP;
>> }
>> } else
>> server->capabilities &= ~CAP_EXTENDED_SECURITY;
>> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>> index 88c84a3..7932813 100644
>> --- a/fs/cifs/connect.c
>> +++ b/fs/cifs/connect.c
>> @@ -1740,6 +1740,9 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
>> if (ses == NULL)
>> goto get_ses_fail;
>>
>> + ses->tilen = 0;
>> + ses->tiblob = NULL;
>> + ses->tidomain = false;
>> /* new SMB session uses our server ref */
>> ses->server = server;
>> if (server->addr.sockAddr6.sin6_family == AF_INET6)
>> diff --git a/fs/cifs/ntlmssp.h b/fs/cifs/ntlmssp.h
>> index 49c9a4e..5d52e4a 100644
>> --- a/fs/cifs/ntlmssp.h
>> +++ b/fs/cifs/ntlmssp.h
>> @@ -61,6 +61,21 @@
>> #define NTLMSSP_NEGOTIATE_KEY_XCH 0x40000000
>> #define NTLMSSP_NEGOTIATE_56 0x80000000
>>
>> +/* Define AV Pair Field IDs */
>> +enum av_field_type {
>> + NTLMSSP_AV_EOL = 0,
>> + NTLMSSP_AV_NB_COMPUTER_NAME,
>> + NTLMSSP_AV_NB_DOMAIN_NAME,
>> + NTLMSSP_AV_DNS_COMPUTER_NAME,
>> + NTLMSSP_AV_DNS_DOMAIN_NAME,
>> + NTLMSSP_AV_DNS_TREE_NAME,
>> + NTLMSSP_AV_FLAGS,
>> + NTLMSSP_AV_TIMESTAMP,
>> + NTLMSSP_AV_RESTRICTION,
>> + NTLMSSP_AV_TARGET_NAME,
>> + NTLMSSP_AV_CHANNEL_BINDINGS
>> +};
>> +
>> /* Although typedefs are not commonly used for structure definitions */
>> /* in the Linux kernel, in this particular case they are useful */
>> /* to more closely match the standards document for NTLMSSP from */
>> diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
>> index 8882012..b857046 100644
>> --- a/fs/cifs/sess.c
>> +++ b/fs/cifs/sess.c
>> @@ -383,6 +383,9 @@ static int decode_ascii_ssetup(char **pbcc_area, int bleft,
>> static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
>> struct cifsSesInfo *ses)
>> {
>> + unsigned int tioffset; /* challenge message target info area */
>> + unsigned int tilen; /* challenge message target info area length */
>> +
>> CHALLENGE_MESSAGE *pblob = (CHALLENGE_MESSAGE *)bcc_ptr;
>>
>> if (blob_len < sizeof(CHALLENGE_MESSAGE)) {
>> @@ -405,6 +408,19 @@ static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
>> /* BB spec says that if AvId field of MsvAvTimestamp is populated then
>> we must set the MIC field of the AUTHENTICATE_MESSAGE */
>>
>> + tioffset = cpu_to_le16(pblob->TargetInfoArray.BufferOffset);
>> + tilen = cpu_to_le16(pblob->TargetInfoArray.Length);
>> + ses->tilen = tilen;
>> + if (ses->tilen) {
>> + ses->tiblob = kmalloc(tilen, GFP_KERNEL);
>> + if (!ses->tiblob) {
>> + cERROR(1, "Challenge target info allocation failure");
>> + ses->tilen = 0;
>> + return -ENOMEM;
>> + }
>> + memcpy(ses->tiblob, bcc_ptr + tioffset, ses->tilen);
>> + }
>> +
>> return 0;
>> }
>>
>> @@ -425,7 +441,7 @@ 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_NT_ONLY | NTLMSSP_NEGOTIATE_NTLM;
>> + NTLMSSP_NEGOTIATE_NTLM;
>> if (ses->server->secMode &
>> (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
>> flags |= NTLMSSP_NEGOTIATE_SIGN;
>> @@ -449,12 +465,14 @@ static void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
>> This function returns the length of the data in the blob */
>> static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
>> struct cifsSesInfo *ses,
>> - const struct nls_table *nls_cp, bool first)
>> + const struct nls_table *nls_cp)
>> {
>> + int rc;
>> + unsigned int size;
>> AUTHENTICATE_MESSAGE *sec_blob = (AUTHENTICATE_MESSAGE *)pbuffer;
>> __u32 flags;
>> unsigned char *tmp;
>> - char ntlm_session_key[CIFS_SESS_KEY_SIZE];
>> + struct ntlmv2_resp ntlmv2_response = {};
>>
>> memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
>> sec_blob->MessageType = NtLmAuthenticate;
>> @@ -462,7 +480,7 @@ 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_NT_ONLY | NTLMSSP_NEGOTIATE_NTLM;
>> + NTLMSSP_NEGOTIATE_NTLM;
>> if (ses->server->secMode &
>> (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
>> flags |= NTLMSSP_NEGOTIATE_SIGN;
>> @@ -477,19 +495,23 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
>> sec_blob->LmChallengeResponse.Length = 0;
>> sec_blob->LmChallengeResponse.MaximumLength = 0;
>>
>> - /* calculate session key, BB what about adding similar ntlmv2 path? */
>> - SMBNTencrypt(ses->password, ses->server->cryptKey, ntlm_session_key);
>> - if (first)
>> - cifs_calculate_session_key(&ses->server->session_key,
>> - ntlm_session_key, ses->password);
>> -
>> - memcpy(tmp, ntlm_session_key, CIFS_SESS_KEY_SIZE);
>> sec_blob->NtChallengeResponse.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> - sec_blob->NtChallengeResponse.Length = cpu_to_le16(CIFS_SESS_KEY_SIZE);
>> - sec_blob->NtChallengeResponse.MaximumLength =
>> - cpu_to_le16(CIFS_SESS_KEY_SIZE);
>> + rc = setup_ntlmv2_rsp(ses, (char *)&ntlmv2_response, nls_cp);
>> + if (rc) {
>> + cERROR(1, "Error %d during NTLMSSP authentication", rc);
>> + goto setup_ntlmv2_ret;
>> + }
>> + size = sizeof(struct ntlmv2_resp);
>> + memcpy(tmp, (char *)&ntlmv2_response, size);
>> + tmp += size;
>> + if (ses->tilen > 0) {
>> + memcpy(tmp, ses->tiblob, ses->tilen);
>> + tmp += ses->tilen;
>> + }
>>
>> - tmp += CIFS_SESS_KEY_SIZE;
>> + sec_blob->NtChallengeResponse.Length = cpu_to_le16(size + ses->tilen);
>> + sec_blob->NtChallengeResponse.MaximumLength =
>> + cpu_to_le16(size + ses->tilen);
>>
>> if (ses->domainName == NULL) {
>> sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> @@ -501,13 +523,24 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
>> len = cifs_strtoUCS((__le16 *)tmp, ses->domainName,
>> MAX_USERNAME_SIZE, nls_cp);
>> len *= 2; /* unicode is 2 bytes each */
>> - len += 2; /* trailing null */
>> sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> sec_blob->DomainName.Length = cpu_to_le16(len);
>> sec_blob->DomainName.MaximumLength = cpu_to_le16(len);
>> tmp += len;
>> }
>>
>> + /* Need to wait till domainName is copied over in the
>> + * ntlmssp response before freeing it if it was allocated.
>> + */
>> + if (ses->tidomain) {
>> + kfree(ses->domainName);
>> + ses->domainName = NULL;
>> + ses->tidomain = false;
>> + }
>> + kfree(ses->tiblob);
>> + ses->tiblob = NULL;
>> + ses->tilen = 0;
>> +
>> if (ses->userName == NULL) {
>> sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> sec_blob->UserName.Length = 0;
>> @@ -518,7 +551,6 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
>> len = cifs_strtoUCS((__le16 *)tmp, ses->userName,
>> MAX_USERNAME_SIZE, nls_cp);
>> len *= 2; /* unicode is 2 bytes each */
>> - len += 2; /* trailing null */
>> sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> sec_blob->UserName.Length = cpu_to_le16(len);
>> sec_blob->UserName.MaximumLength = cpu_to_le16(len);
>> @@ -533,6 +565,8 @@ static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
>> sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - pbuffer);
>> sec_blob->SessionKey.Length = 0;
>> sec_blob->SessionKey.MaximumLength = 0;
>> +
>> +setup_ntlmv2_ret:
>> return tmp - pbuffer;
>> }
>>
>> @@ -545,19 +579,6 @@ static void setup_ntlmssp_neg_req(SESSION_SETUP_ANDX *pSMB,
>>
>> return;
>> }
>> -
>> -static int setup_ntlmssp_auth_req(SESSION_SETUP_ANDX *pSMB,
>> - struct cifsSesInfo *ses,
>> - const struct nls_table *nls, bool first_time)
>> -{
>> - int bloblen;
>> -
>> - bloblen = build_ntlmssp_auth_blob(&pSMB->req.SecurityBlob[0], ses, nls,
>> - first_time);
>> - pSMB->req.SecurityBlobLength = cpu_to_le16(bloblen);
>> -
>> - return bloblen;
>> -}
>> #endif
>>
>> int
>> @@ -580,6 +601,8 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
>> struct key *spnego_key = NULL;
>> __le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
>> bool first_time;
>> + int blob_len;
>> + char *ntlmsspblob = NULL;
>>
>> if (ses == NULL)
>> return -EINVAL;
>> @@ -729,12 +752,24 @@ ssetup_ntlmssp_authenticate:
>> cpu_to_le16(sizeof(struct ntlmv2_resp));
>>
>> /* calculate session key */
>> - setup_ntlmv2_rsp(ses, v2_sess_key, nls_cp);
>> - /* FIXME: calculate MAC key */
>> + rc = setup_ntlmv2_rsp(ses, v2_sess_key, nls_cp);
>> + if (rc) {
>> + cERROR(1, "Error %d during NTLMv2 authentication", rc);
>> + kfree(v2_sess_key);
>> + goto ssetup_exit;
>> + }
>> memcpy(bcc_ptr, (char *)v2_sess_key,
>> - sizeof(struct ntlmv2_resp));
>> + sizeof(struct ntlmv2_resp));
>> bcc_ptr += sizeof(struct ntlmv2_resp);
>> kfree(v2_sess_key);
>> + if (ses->tilen > 0) {
>> + memcpy(bcc_ptr, ses->tiblob, ses->tilen);
>> + bcc_ptr += ses->tilen;
>> + /* we never did allocate ses->domainName to free */
>> + kfree(ses->tiblob);
>> + ses->tiblob = NULL;
>> + ses->tilen = 0;
>> + }
>> if (ses->capabilities & CAP_UNICODE) {
>> if (iov[0].iov_len % 2) {
>> *bcc_ptr = 0;
>> @@ -815,12 +850,28 @@ ssetup_ntlmssp_authenticate:
>> if (phase == NtLmNegotiate) {
>> setup_ntlmssp_neg_req(pSMB, ses);
>> iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
>> + iov[1].iov_base = &pSMB->req.SecurityBlob[0];
>> } else if (phase == NtLmAuthenticate) {
>> - int blob_len;
>> - blob_len = setup_ntlmssp_auth_req(pSMB, ses,
>> - nls_cp,
>> - first_time);
>> + /* 5 is an empirical value, large enought to
>> + * hold authenticate message, max 10 of
>> + * av paris, doamin,user,workstation mames,
>> + * flags etc..
>> + */
>> + ntlmsspblob = kmalloc(
>> + 5*sizeof(struct _AUTHENTICATE_MESSAGE),
>> + GFP_KERNEL);
>> + if (!ntlmsspblob) {
>> + cERROR(1, "Can't allocate NTLMSSP");
>> + rc = -ENOMEM;
>> + goto ssetup_exit;
>> + }
>> +
>> + blob_len = build_ntlmssp_auth_blob(ntlmsspblob,
>> + ses, nls_cp);
>> iov[1].iov_len = blob_len;
>> + iov[1].iov_base = ntlmsspblob;
>> + pSMB->req.SecurityBlobLength =
>> + cpu_to_le16(blob_len);
>> /* Make sure that we tell the server that we
>> are using the uid that it just gave us back
>> on the response (challenge) */
>> @@ -830,7 +881,6 @@ ssetup_ntlmssp_authenticate:
>> rc = -ENOSYS;
>> goto ssetup_exit;
>> }
>> - iov[1].iov_base = &pSMB->req.SecurityBlob[0];
>> /* unicode strings must be word aligned */
>> if ((iov[0].iov_len + iov[1].iov_len) % 2) {
>> *bcc_ptr = 0;
>> @@ -931,6 +981,7 @@ ssetup_exit:
>> key_put(spnego_key);
>> }
>> kfree(str_area);
>> + kfree(ntlmsspblob);
> ^^^^^
> I think you should set the above pointer to NULL too. It's a bit hard
> to follow the code in CIFS_SessSetup, but if it'll ever be possible to
> make another trip to the server after the NtLmAuthenticate phase, then
> you'll potentially double-free this pointer. Some defensive coding here
> would be good.
Sure. But as far as I know, there are only three types of packets
exchanged in NTLM protocol and authenticate type is the last a client sends.
>
>> if (resp_buf_type == CIFS_SMALL_BUFFER) {
>> cFYI(1, "ssetup freeing small buf %p", iov[0].iov_base);
>> cifs_small_buf_release(iov[0].iov_base);
>
>
> --
> Jeff Layton <jlayton@xxxxxxxxx>
>
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