1 /*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source. A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12 /*
13 * Copyright 2017 Nexenta Systems, Inc. All rights reserved.
14 * Copyright 2020 RackTop Systems, Inc.
15 */
16
17 /*
18 * Dispatch function for SMB2_SESSION_SETUP
19 *
20 * Note that the Capabilities supplied in this request are an inferior
21 * subset of those given to us previously in the SMB2 Negotiate request.
22 * We need to remember the full set of capabilities from SMB2 Negotiate,
23 * and therefore ignore the subset of capabilities supplied here.
24 */
25
26 #include <smbsrv/smb2_kproto.h>
27
28 static void smb2_ss_adjust_credits(smb_request_t *);
29
30 smb_sdrc_t
smb2_session_setup(smb_request_t * sr)31 smb2_session_setup(smb_request_t *sr)
32 {
33 smb_arg_sessionsetup_t *sinfo;
34 uint16_t StructureSize;
35 uint8_t Flags;
36 uint8_t SecurityMode;
37 uint32_t Capabilities; /* ignored - see above */
38 uint32_t Channel;
39 uint16_t SecBufOffset;
40 uint16_t SecBufLength;
41 uint64_t PrevSsnId;
42 uint16_t SessionFlags;
43 uint32_t status;
44 int skip;
45 int rc = 0;
46
47 sinfo = smb_srm_zalloc(sr, sizeof (smb_arg_sessionsetup_t));
48 sr->sr_ssetup = sinfo;
49
50 rc = smb_mbc_decodef(
51 &sr->smb_data, "wbbllwwq",
52 &StructureSize, /* w */
53 &Flags, /* b */
54 &SecurityMode, /* b */
55 &Capabilities, /* l */
56 &Channel, /* l */
57 &SecBufOffset, /* w */
58 &SecBufLength, /* w */
59 &PrevSsnId); /* q */
60 if (rc)
61 return (SDRC_ERROR);
62
63 /*
64 * We're normally positioned at the security buffer now,
65 * but there could be some padding before it.
66 */
67 skip = (SecBufOffset + sr->smb2_cmd_hdr) -
68 sr->smb_data.chain_offset;
69 if (skip < 0)
70 return (SDRC_ERROR);
71 if (skip > 0)
72 (void) smb_mbc_decodef(&sr->smb_data, "#.", skip);
73
74 /*
75 * Get the security buffer
76 */
77 sinfo->ssi_iseclen = SecBufLength;
78 sinfo->ssi_isecblob = smb_srm_zalloc(sr, sinfo->ssi_iseclen);
79 rc = smb_mbc_decodef(&sr->smb_data, "#c",
80 sinfo->ssi_iseclen, sinfo->ssi_isecblob);
81 if (rc)
82 return (SDRC_ERROR);
83
84 /*
85 * Decoded everything. Dtrace probe,
86 * then no more early returns.
87 */
88 DTRACE_SMB2_START(op__SessionSetup, smb_request_t *, sr);
89
90 /*
91 * [MS-SMB2] 3.3.5.5 Receiving an SMB2 SESSION_SETUP Request
92 *
93 * If we support 3.x, RejectUnencryptedAccess is TRUE,
94 * global EncryptData is TRUE, but we're not talking
95 * 3.x or the client doesn't support encryption,
96 * return ACCESS_DENIED.
97 *
98 * If RejectUnencryptedAccess is TRUE, we force max_protocol
99 * to at least 3.0.
100 */
101 if (sr->sr_server->sv_cfg.skc_encrypt == SMB_CONFIG_REQUIRED &&
102 (sr->session->dialect < SMB_VERS_3_0 ||
103 !SMB3_CLIENT_ENCRYPTS(sr))) {
104 status = NT_STATUS_ACCESS_DENIED;
105 goto errout;
106 }
107
108 /*
109 * SMB3 multi-channel features are not supported.
110 * Once they are, this will check the dialect and
111 * whether multi-channel was negotiated, i.e.
112 * if (sr->session->dialect < SMB_VERS_3_0 ||
113 * s->IsMultiChannelCapable == False)
114 * return (error...)
115 */
116 if (Flags & SMB2_SESSION_FLAG_BINDING) {
117 status = NT_STATUS_REQUEST_NOT_ACCEPTED;
118 goto errout;
119 }
120
121 /*
122 * The real auth. work happens in here.
123 */
124 status = smb_authenticate_ext(sr);
125
126 SecBufOffset = SMB2_HDR_SIZE + 8;
127 SecBufLength = sinfo->ssi_oseclen;
128 SessionFlags = 0;
129
130 switch (status) {
131
132 case NT_STATUS_SUCCESS: /* Authenticated */
133 if ((sr->uid_user->u_flags & SMB_USER_FLAG_GUEST) != 0)
134 SessionFlags |= SMB2_SESSION_FLAG_IS_GUEST;
135 if ((sr->uid_user->u_flags & SMB_USER_FLAG_ANON) != 0)
136 SessionFlags |= SMB2_SESSION_FLAG_IS_NULL;
137 if (sr->uid_user->u_encrypt != SMB_CONFIG_DISABLED)
138 SessionFlags |= SMB2_SESSION_FLAG_ENCRYPT_DATA;
139 smb2_ss_adjust_credits(sr);
140
141 /*
142 * PrevSsnId is a session that the client is reporting as
143 * having gone away, and for which we might not yet have seen
144 * a disconnect. We need to log off the previous session so
145 * any durable handles in that session will become orphans
146 * that can be reclaimed in this new session. Note that
147 * either zero or the _current_ session ID means there is
148 * no previous session to logoff.
149 */
150 if (PrevSsnId != 0 &&
151 PrevSsnId != sr->smb2_ssnid)
152 smb_server_logoff_ssnid(sr, PrevSsnId);
153 break;
154
155 /*
156 * This is not really an error, but tells the client
157 * it should send another session setup request.
158 * Not smb2_put_error because we send a payload.
159 */
160 case NT_STATUS_MORE_PROCESSING_REQUIRED:
161 sr->smb2_status = status;
162 break;
163
164 default:
165 errout:
166 SecBufLength = 0;
167 sr->smb2_status = status;
168 break;
169 }
170
171 /* sr->smb2_status set above */
172 DTRACE_SMB2_DONE(op__SessionSetup, smb_request_t *, sr);
173
174 /*
175 * SMB2 Session Setup reply
176 */
177
178 rc = smb_mbc_encodef(
179 &sr->reply,
180 "wwww#c",
181 9, /* StructSize */ /* w */
182 SessionFlags, /* w */
183 SecBufOffset, /* w */
184 SecBufLength, /* w */
185 SecBufLength, /* # */
186 sinfo->ssi_osecblob); /* c */
187 if (rc)
188 sr->smb2_status = NT_STATUS_INTERNAL_ERROR;
189
190 return (SDRC_SUCCESS);
191 }
192
193 /*
194 * After a successful authentication, raise s_max_credits up to the
195 * normal maximum that clients are allowed to request. Also, if we
196 * haven't yet given them their initial credits, do that now.
197 *
198 * Normally, clients will request some credits with session setup,
199 * but in case they don't request enough to raise s_cur_credits
200 * up to the configured initial_credits, increase the requested
201 * credits of this SR sufficiently to make that happen. The actual
202 * increase happens in the dispatch code after we return.
203 */
204 static void
smb2_ss_adjust_credits(smb_request_t * sr)205 smb2_ss_adjust_credits(smb_request_t *sr)
206 {
207 smb_session_t *s = sr->session;
208
209 mutex_enter(&s->s_credits_mutex);
210 s->s_max_credits = s->s_cfg.skc_maximum_credits;
211
212 if (s->s_cur_credits < s->s_cfg.skc_initial_credits) {
213 uint16_t grant;
214
215 /* How many credits we want to grant with this SR. */
216 grant = s->s_cfg.skc_initial_credits - s->s_cur_credits;
217
218 /*
219 * Do we need to increase the smb2_credit_request?
220 * One might prefer to read this expression as:
221 * ((credit_request - credit_charge) < grant)
222 * but we know credit_charge == 1 and would rather not
223 * deal with a possibly negative value on the left,
224 * so adding credit_charge to both sides...
225 */
226 if (sr->smb2_credit_request < (grant + 1)) {
227 sr->smb2_credit_request = (grant + 1);
228 }
229 }
230
231 mutex_exit(&s->s_credits_mutex);
232 }
233