Make IPC a regular tcon and fix SMB2 domain-based DFS

* Remove ses->ipc_tid.
* Make IPC$ regular tcon by having it stored in the session tcon list.

* Add a direct pointer to it in ses->tcon_ipc.
* Distinguish PIPE tcon from IPC tcon by adding a tcon->pipe flag. All IPC tcons are pipes but not all pipes are IPC.
* All TreeConnect functions now cannot take a NULL tcon object.

The IPC tcon has the same lifetime as the session it belongs to. It is created when the session is created and destroyed when the session is destroyed.

Since no mounts directly refer to the IPC tcon, its refcount should always be 0. Thus we make sure cifs_put_tcon() skips it.

If the mount request resulting in a new session being created requires encryption, try to require it too for IPC.

NOTE TO BACKPORTER: the previous SERVER_NAME_LENGTH change MUST be included with this.

Signed-off-by Aurelien Aptel <aaptel-IBi9RG/[email protected]>

---
 fs/cifs/cifsglob.h |   7 ++-
 fs/cifs/cifssmb.c  |   5 +-
 fs/cifs/connect.c  | 159 ++++++++++++++++++++++++++++++++++++++++-------------
 fs/cifs/inode.c    |   2 +-
 fs/cifs/smb2pdu.c  |  32 ++---------
 5 files changed, 134 insertions(+), 71 deletions(-)

fs/cifs/cifsglob.h +4 -3

index eca386d8dcfb..804ec79af5e1 100644
@@ -822,12 +822,12 @@ static inline void cifs_set_net_ns(struct TCP_Server_Info *srv, struct net *net)
 struct cifs_ses {
        struct list_head smb_ses_list;
        struct list_head tcon_list;
+       struct cifs_tcon *tcon_ipc;
        struct mutex session_mutex;
        struct TCP_Server_Info *server; /* pointer to server info */
        int ses_count;          /* reference counter */
        enum statusEnum status;
        unsigned overrideSecFlg;  /* if non-zero override global sec flags */
-       __u32 ipc_tid;          /* special tid for connection to IPC share */
        char *serverOS;         /* name of operating system underlying server */
        char *serverNOS;        /* name of network operating system of server */
        char *serverDomain;     /* security realm of server */

@@ -930,7 +930,9 @@ struct cifs_tcon {
        FILE_SYSTEM_DEVICE_INFO fsDevInfo;
        FILE_SYSTEM_ATTRIBUTE_INFO fsAttrInfo; /* ok if fs name truncated */
        FILE_SYSTEM_UNIX_INFO fsUnixInfo;
-       bool ipc:1;             /* set if connection to IPC$ eg for RPC/PIPES */
+       bool ipc:1;   /* set if connection to IPC$ share (always also pipe) */
+       bool pipe:1;  /* set if connection to pipe share */
+       bool print:1; /* set if connection to printer share */
        bool retry:1;
        bool nocase:1;
        bool seal:1;      /* transport encryption for this mounted share */

@@ -943,7 +945,6 @@ struct cifs_tcon {
        bool need_reopen_files:1; /* need to reopen tcon file handles */
        bool use_resilient:1; /* use resilient instead of durable handles */
        bool use_persistent:1; /* use persistent instead of durable handles */
-       bool print:1;           /* set if connection to printer share */
        __le32 capabilities;
        __u32 share_flags;
        __u32 maximal_access;

fs/cifs/cifssmb.c +3 -2

index 35dc5bf01ee2..2f8dea905ef9 100644
@@ -4822,8 +4822,9 @@ CIFSGetDFSRefer(const unsigned int xid, struct cifs_ses *ses,
        *target_nodes = NULL;
 
        cifs_dbg(FYI, "In GetDFSRefer the path %s\n", search_name);
-       if (ses == NULL)
+       if (ses == NULL || ses->tcon_ipc == NULL)
                return -ENODEV;
+
 getDFSRetry:
        rc = smb_init(SMB_COM_TRANSACTION2, 15, NULL, (void **) &pSMB,
                      (void **) &pSMBr);

@@ -4833,7 +4834,7 @@ CIFSGetDFSRefer(const unsigned int xid, struct cifs_ses *ses,
        /* server pointer checked in called function,
        but should never be null here anyway */
        pSMB->hdr.Mid = get_next_mid(ses->server);
-       pSMB->hdr.Tid = ses->ipc_tid;
+       pSMB->hdr.Tid = ses->tcon_ipc->tid;
        pSMB->hdr.Uid = ses->Suid;
        if (ses->capabilities & CAP_STATUS32)
                pSMB->hdr.Flags2 |= SMBFLG2_ERR_STATUS;

fs/cifs/connect.c +85 -1

index 0bfc2280436d..5ae393fe0c5d 100644
@@ -353,7 +353,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
        list_for_each(tmp, &server->smb_ses_list) {
                ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
                ses->need_reconnect = true;
-               ses->ipc_tid = 0;
                list_for_each(tmp2, &ses->tcon_list) {
                        tcon = list_entry(tmp2, struct cifs_tcon, tcon_list);
                        tcon->need_reconnect = true;

@@ -2381,6 +2380,104 @@ static int match_session(struct cifs_ses *ses, struct smb_vol *vol)
        return 1;
 }
 
+/**
+ * cifs_setup_ipc - helper to setup the IPC tcon for the session
+ *
+ * A new IPC connection is made and added to the session tcon list
+ * (also accessible through ses->tcon_ipc). The IPC tcon has the same
+ * lifetime as the session.
+ */
+static int
+cifs_setup_ipc(struct cifs_ses *ses, struct smb_vol *volume_info)
+{
+       int rc = 0, xid;
+       struct cifs_tcon *tcon;
+       struct nls_table *nls_codepage;
+       char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
+       bool seal = false;
+
+       /*
+        * If the mount request that resulted in the creation of the
+        * session requires encryption, force IPC to be encrypted too.
+        */
+       if (volume_info->seal) {
+               if (ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
+                       seal = true;
+               else {
+                       cifs_dbg(VFS,
+                                "IPC: server doesn't support encryption\n");
+                       return -EOPNOTSUPP;
+               }
+       }
+
+       tcon = tconInfoAlloc();
+       if (tcon == NULL)
+               return -ENOMEM;
+
+       snprintf(unc, sizeof(unc), "\\\\%s\\IPC$", ses->serverName);
+
+       /* cannot fail */
+       nls_codepage = load_nls_default();
+
+       xid = get_xid();
+       tcon->ses = ses;
+       tcon->ipc = true;
+       tcon->seal = seal;
+       rc = ses->server->ops->tree_connect(xid, ses, unc, tcon, nls_codepage);
+       free_xid(xid);
+
+       if (rc) {
+               cifs_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
+               tconInfoFree(tcon);
+               goto out;
+       }
+
+       cifs_dbg(FYI, "IPC tcon rc = %d ipc tid = %d\n", rc, tcon->tid);
+
+       spin_lock(&cifs_tcp_ses_lock);
+       list_add(&tcon->tcon_list, &ses->tcon_list);
+       ses->tcon_ipc = tcon;
+       spin_unlock(&cifs_tcp_ses_lock);
+
+out:
+       unload_nls(nls_codepage);
+       return rc;
+}
+
+/**
+ * cifs_free_ipc - helper to release the session IPC tcon
+ *
+ * Needs to be called everytime a session is destroyed
+ */
+static int
+cifs_free_ipc(struct cifs_ses *ses)
+{
+       int rc = 0, xid;
+       struct cifs_tcon *tcon;
+
+       spin_lock(&cifs_tcp_ses_lock);
+       tcon = ses->tcon_ipc;
+       if (tcon == NULL) {
+               spin_unlock(&cifs_tcp_ses_lock);
+               return 0;
+       }
+       list_del_init(&tcon->tcon_list);
+       spin_unlock(&cifs_tcp_ses_lock);
+
+       if (ses->server->ops->tree_disconnect) {

fs/cifs/connect.c +18 -16

+       return rc;
+}
+
 static struct cifs_ses *
 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
 {

@@ -2421,6 +2518,8 @@ cifs_put_smb_ses(struct cifs_ses *ses)
                ses->status = CifsExiting;
        spin_unlock(&cifs_tcp_ses_lock);
 
+       cifs_free_ipc(ses);
+
        if (ses->status == CifsExiting && server->ops->logoff) {
                xid = get_xid();
                rc = server->ops->logoff(xid, ses);

@@ -2665,6 +2764,9 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
        spin_unlock(&cifs_tcp_ses_lock);
 
        free_xid(xid);
+
+       cifs_setup_ipc(ses, volume_info);
+
        return ses;
 
 get_ses_fail:

@@ -2709,8 +2811,16 @@ void
 cifs_put_tcon(struct cifs_tcon *tcon)
 {
        unsigned int xid;
-       struct cifs_ses *ses = tcon->ses;
+       struct cifs_ses *ses;
+
+       /*
+        * IPC tcon share the lifetime of their session and are
+        * destroyed in the session put function
+        */
+       if (tcon == NULL || tcon->ipc)
+               return;
 
+       ses = tcon->ses;
        cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
        spin_lock(&cifs_tcp_ses_lock);
        if (--tcon->tc_count > 0) {

@@ -2986,39 +3096,17 @@ get_dfs_path(const unsigned int xid, struct cifs_ses *ses, const char *old_path,
             const struct nls_table *nls_codepage, unsigned int *num_referrals,
             struct dfs_info3_param **referrals, int remap)
 {
-       char *temp_unc;
        int rc = 0;
 
-       if (!ses->server->ops->tree_connect || !ses->server->ops->get_dfs_refer)
+       if (!ses->server->ops->get_dfs_refer)
                return -ENOSYS;
 
        *num_referrals = 0;
        *referrals = NULL;
 
-       if (ses->ipc_tid == 0) {
-               temp_unc = kmalloc(2 /* for slashes */ +
-                       strnlen(ses->serverName, SERVER_NAME_LEN_WITH_NULL * 2)
-                               + 1 + 4 /* slash IPC$ */ + 2, GFP_KERNEL);
-               if (temp_unc == NULL)
-                       return -ENOMEM;
-               temp_unc[0] = '\\';
-               temp_unc[1] = '\\';
-               strcpy(temp_unc + 2, ses->serverName);
-               strcpy(temp_unc + 2 + strlen(ses->serverName), "\\IPC$");
-               rc = ses->server->ops->tree_connect(xid, ses, temp_unc, NULL,
-                                                   nls_codepage);
-               cifs_dbg(FYI, "Tcon rc = %d ipc_tid = %d\n", rc, ses->ipc_tid);

fs/cifs/connect.c +9 -10

-
+       rc = ses->server->ops->get_dfs_refer(xid, ses, old_path,
+                                            referrals, num_referrals,
+                                            nls_codepage, remap);
        return rc;
 }
 

@@ -3783,7 +3871,7 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
                tcon->unix_ext = 0; /* server does not support them */
 
        /* do not care if a following call succeed - informational */
-       if (!tcon->ipc && server->ops->qfs_tcon)
+       if (!tcon->pipe && server->ops->qfs_tcon)
                server->ops->qfs_tcon(xid, tcon);
 
        cifs_sb->wsize = server->ops->negotiate_wsize(tcon, volume_info);

@@ -3913,8 +4001,7 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 }
 
 /*
- * Issue a TREE_CONNECT request. Note that for IPC$ shares, that the tcon
- * pointer may be NULL.
+ * Issue a TREE_CONNECT request.
  */
 int
 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,

@@ -3950,7 +4037,7 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
        pSMB->AndXCommand = 0xFF;
        pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
        bcc_ptr = &pSMB->Password[0];
-       if (!tcon || (ses->server->sec_mode & SECMODE_USER)) {
+       if (tcon->pipe || (ses->server->sec_mode & SECMODE_USER)) {
                pSMB->PasswordLength = cpu_to_le16(1);  /* minimum */
                *bcc_ptr = 0; /* password is null byte */
                bcc_ptr++;              /* skip password */

@@ -4022,7 +4109,7 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                         0);
 
        /* above now done in SendReceive */
-       if ((rc == 0) && (tcon != NULL)) {
+       if (rc == 0) {
                bool is_unicode;
 
                tcon->tidStatus = CifsGood;

@@ -4042,7 +4129,8 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                        if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
                            (bcc_ptr[2] == 'C')) {
                                cifs_dbg(FYI, "IPC connection\n");
-                               tcon->ipc = 1;
+                               tcon->ipc = true;
+                               tcon->pipe = true;
                        }
                } else if (length == 2) {
                        if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {

@@ -4069,9 +4157,6 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                else
                        tcon->Flags = 0;
                cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
-       } else if ((rc == 0) && tcon == NULL) {
-               /* all we need to save for IPC$ connection */
-               ses->ipc_tid = smb_buffer_response->Tid;
        }
 
        cifs_buf_release(smb_buffer);

fs/cifs/inode.c +1 -1

index ecb99079363a..8f9a8cc7cc62 100644
@@ -1049,7 +1049,7 @@ struct inode *cifs_root_iget(struct super_block *sb)
        tcon->resource_id = CIFS_I(inode)->uniqueid;
 #endif
 
-       if (rc && tcon->ipc) {
+       if (rc && tcon->pipe) {
                cifs_dbg(FYI, "ipc connection - fake read inode\n");
                spin_lock(&inode->i_lock);
                inode->i_mode |= S_IFDIR;

fs/cifs/smb2pdu.c +4 -29

index 01346b8b6edb..a5c94f8308eb 100644
@@ -1283,8 +1283,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
        }
 
        /* SMB2 TREE_CONNECT request must be called with TreeId == 0 */
-       if (tcon)
-               tcon->tid = 0;
+       tcon->tid = 0;
 
        rc = small_smb2_init(SMB2_TREE_CONNECT, tcon, (void **) &req);
        if (rc) {

@@ -1292,15 +1291,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
                return rc;
        }
 
-       if (tcon == NULL) {
-               if ((ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA))
-                       flags |= CIFS_TRANSFORM_REQ;
-
-               /* since no tcon, smb2_init can not do this, so do here */
-               req->hdr.sync_hdr.SessionId = ses->Suid;
-               if (ses->server->sign)
-                       req->hdr.sync_hdr.Flags |= SMB2_FLAGS_SIGNED;
-       } else if (encryption_required(tcon))
+       if (encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;
 
        iov[0].iov_base = (char *)req;

@@ -1328,21 +1319,16 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
                goto tcon_error_exit;
        }
 
-       if (tcon == NULL) {
-               ses->ipc_tid = rsp->hdr.sync_hdr.TreeId;
-               goto tcon_exit;
-       }
-
        switch (rsp->ShareType) {
        case SMB2_SHARE_TYPE_DISK:
                cifs_dbg(FYI, "connection to disk share\n");
                break;
        case SMB2_SHARE_TYPE_PIPE:
-               tcon->ipc = true;
+               tcon->pipe = true;
                cifs_dbg(FYI, "connection to pipe share\n");
                break;
        case SMB2_SHARE_TYPE_PRINT:
-               tcon->ipc = true;
+               tcon->print = true;
                cifs_dbg(FYI, "connection to printer\n");
                break;
        default:

@@ -1913,16 +1899,6 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
        if (rc)
                return rc;
 
-       if (use_ipc) {
-               if (ses->ipc_tid == 0) {
-                       cifs_small_buf_release(req);
-                       return -ENOTCONN;
-               }
-
-               cifs_dbg(FYI, "replacing tid 0x%x with IPC tid 0x%x\n",
-                        req->hdr.sync_hdr.TreeId, ses->ipc_tid);
-               req->hdr.sync_hdr.TreeId = ses->ipc_tid;
-       }
        if (encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;
 
--

2.12.3

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Minor: it should probably work this way, but since we set ses->tcon_ipc under a spinlock in cifs_setup_ipc(), it would be better to do something similar here.

fs/cifs/connect.c get_dfs_path(const unsigned int xid, struct cifs_ses *ses, const char *old_path, · line 3020

Quoted 4 lines

fs/cifs/connect.c +0 -4

-       /*
-        * BB - map targetUNCs to dfs_info3 structures, here or in
-        * ses->server->ops->get_dfs_refer.
-        */

Is this no longer needed?

Quoted 1 line · Pavel Shilovskiy

Minor: it should probably work this way, but since we set ses->tcon_ipc under a spinlock in cifs_setup_ipc(), it would be better to do something similar here.

I was actually thinking that the spinlock might not be necessary for that pointer. It's always only set at session creation (new tcon) and destruction (to null). In between, it's only going to be read. What do you think?

Quoted 6 lines

Quoted 5 lines

fs/cifs/connect.c +0 -4

-       /*
-        * BB - map targetUNCs to dfs_info3 structures, here or in
-        * ses->server->ops->get_dfs_refer.
-        */

Quoted 1 line

Is this no longer needed?

If you are talking about the tcon creation, it is now done all the time at session creation. If you are talking about that specific comment, I believe it's already done now in parse_dfs_referrals(). That function parses the packet into dfs_info3_param structures.

I agree that accessing ses->tcon_ipc is not necessary to be under spinlock. Btw, why should we put this tcon to the list at the 1st place? We can leave to be accessed only by ses->tcon_ipc and do not bother with spinlocks at all.

Since IPC now has a tcon object, the caller can just pass it. This allows domain-based DFS requests to work with smb2+.

Link https://bugzilla.samba.org/show_bug.cgi?id=12917

Fixes 9d49640a21bf ("CIFS: implement get_dfs_refer for SMB2+")

Signed-off-by Aurelien Aptel <aaptel-IBi9RG/[email protected]>

---
 fs/cifs/smb2file.c  |  2 +-
 fs/cifs/smb2ops.c   | 53 ++++++++++++++++++++++-------------------------------
 fs/cifs/smb2pdu.c   |  4 +---
 fs/cifs/smb2proto.h |  3 +--
 4 files changed, 25 insertions(+), 37 deletions(-)

fs/cifs/smb2file.c +1 -1

index b4b1f0305f29..12af5dba742b 100644
@@ -74,7 +74,7 @@ smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
                nr_ioctl_req.Reserved = 0;
                rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
                        fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        (char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
                        NULL, NULL /* no return info */);
                if (rc == -EOPNOTSUPP) {

fs/cifs/smb2ops.c +18 -18

index ed88ab8a4774..1d9907da96f4 100644
@@ -283,7 +283,6 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon)
 
        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                        FSCTL_QUERY_NETWORK_INTERFACE_INFO, true /* is_fsctl */,
-                       false /* use_ipc */,
                        NULL /* no data input */, 0 /* no data input */,
                        (char **)&out_buf, &ret_data_len);
        if (rc != 0)

@@ -782,7 +781,6 @@ SMB2_request_res_key(const unsigned int xid, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, persistent_fid, volatile_fid,
                        FSCTL_SRV_REQUEST_RESUME_KEY, true /* is_fsctl */,
-                       false /* use_ipc */,
                        NULL, 0 /* no input */,
                        (char **)&res_key, &ret_data_len);
 

@@ -848,8 +846,7 @@ smb2_copychunk_range(const unsigned int xid,
                /* Request server copy to target from src identified by key */
                rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid, FSCTL_SRV_COPYCHUNK_WRITE,
-                       true /* is_fsctl */, false /* use_ipc */,
-                       (char *)pcchunk,
+                       true /* is_fsctl */, (char *)pcchunk,
                        sizeof(struct copychunk_ioctl), (char **)&retbuf,
                        &ret_data_len);
                if (rc == 0) {

@@ -1006,7 +1003,7 @@ static bool smb2_set_sparse(const unsigned int xid, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_SPARSE,
-                       true /* is_fctl */, false /* use_ipc */,
+                       true /* is_fctl */,
                        &setsparse, 1, NULL, NULL);
        if (rc) {
                tcon->broken_sparse_sup = true;

@@ -1077,7 +1074,7 @@ smb2_duplicate_extents(const unsigned int xid,
        rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid,
                        FSCTL_DUPLICATE_EXTENTS_TO_FILE,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        (char *)&dup_ext_buf,
                        sizeof(struct duplicate_extents_to_file),
                        NULL,

@@ -1112,7 +1109,7 @@ smb3_set_integrity(const unsigned int xid, struct cifs_tcon *tcon,
        return SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid,
                        FSCTL_SET_INTEGRITY_INFORMATION,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        (char *)&integr_info,
                        sizeof(struct fsctl_set_integrity_information_req),
                        NULL,

@@ -1132,7 +1129,7 @@ smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid,
                        FSCTL_SRV_ENUMERATE_SNAPSHOTS,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        NULL, 0 /* no input data */,
                        (char **)&retbuf,
                        &ret_data_len);

@@ -1351,16 +1348,20 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
        cifs_dbg(FYI, "smb2_get_dfs_refer path <%s>\n", search_name);
 
        /*
-        * Use any tcon from the current session. Here, the first one.
+        * Try to use the IPC tcon, otherwise just use any
         */
-       spin_lock(&cifs_tcp_ses_lock);
-       tcon = list_first_entry_or_null(&ses->tcon_list, struct cifs_tcon,
-                                       tcon_list);
-       if (tcon)
-               tcon->tc_count++;
-       spin_unlock(&cifs_tcp_ses_lock);
+       tcon = ses->tcon_ipc;
+       if (tcon == NULL) {
+               spin_lock(&cifs_tcp_ses_lock);
+               tcon = list_first_entry_or_null(&ses->tcon_list,
+                                               struct cifs_tcon,
+                                               tcon_list);
+               if (tcon)
+                       tcon->tc_count++;
+               spin_unlock(&cifs_tcp_ses_lock);
+       }
 
-       if (!tcon) {
+       if (tcon == NULL) {
                cifs_dbg(VFS, "session %p has no tcon available for a dfs referral request\n",
                         ses);
                rc = -ENOTCONN;

@@ -1389,20 +1390,11 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
        memcpy(dfs_req->RequestFileName, utf16_path, utf16_path_len);
 
        do {
-               /* try first with IPC */
                rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                                FSCTL_DFS_GET_REFERRALS,
-                               true /* is_fsctl */, true /* use_ipc */,
+                               true /* is_fsctl */,

Is it safe to try IPC share only and not retry with any normal tcon in the case of ENOTCONN like the current code does?

* Remove ses->ipc_tid.
* Make IPC$ regular tcon.
* Add a direct pointer to it in ses->tcon_ipc.
* Distinguish PIPE tcon from IPC tcon by adding a tcon->pipe flag. All IPC tcons are pipes but not all pipes are IPC.
* All TreeConnect functions now cannot take a NULL tcon object.

The IPC tcon has the same lifetime as the session it belongs to. It is created when the session is created and destroyed when the session is destroyed.

Since no mounts directly refer to the IPC tcon, its refcount should always be set to initialisation value (1). Thus we make sure cifs_put_tcon() skips it.

If the mount request resulting in a new session being created requires encryption, try to require it too for IPC.

* set SERVER_NAME_LENGTH to serverName actual size

The maximum length of an ipv6 string representation is defined in INET6_ADDRSTRLEN as 45+1 for null but lets keep what we know works.

Signed-off-by Aurelien Aptel <aaptel-IBi9RG/[email protected]>

---
 fs/cifs/cifsglob.h |  14 ++---
 fs/cifs/cifssmb.c  |   7 +--
 fs/cifs/connect.c  | 150 ++++++++++++++++++++++++++++++++++++++++-------------
 fs/cifs/inode.c    |   2 +-
 fs/cifs/smb2pdu.c  |  36 +++----------
 5 files changed, 133 insertions(+), 76 deletions(-)

fs/cifs/cifsglob.h +7 -7

index 678e638c1e69..48f7c197cd2d 100644
@@ -64,8 +64,8 @@
 #define RFC1001_NAME_LEN 15
 #define RFC1001_NAME_LEN_WITH_NULL (RFC1001_NAME_LEN + 1)
 
-/* currently length of NIP6_FMT */
-#define SERVER_NAME_LENGTH 40
+/* maximum length of ip addr as a string (including ipv6 and sctp) */
+#define SERVER_NAME_LENGTH 80
 #define SERVER_NAME_LEN_WITH_NULL     (SERVER_NAME_LENGTH + 1)
 
 /* echo interval in seconds */

@@ -833,12 +833,12 @@ static inline void cifs_set_net_ns(struct TCP_Server_Info *srv, struct net *net)
 struct cifs_ses {
        struct list_head smb_ses_list;
        struct list_head tcon_list;
+       struct cifs_tcon *tcon_ipc;
        struct mutex session_mutex;
        struct TCP_Server_Info *server; /* pointer to server info */
        int ses_count;          /* reference counter */
        enum statusEnum status;
        unsigned overrideSecFlg;  /* if non-zero override global sec flags */
-       __u32 ipc_tid;          /* special tid for connection to IPC share */
        char *serverOS;         /* name of operating system underlying server */
        char *serverNOS;        /* name of network operating system of server */
        char *serverDomain;     /* security realm of server */

@@ -846,8 +846,7 @@ struct cifs_ses {
        kuid_t linux_uid;       /* overriding owner of files on the mount */
        kuid_t cred_uid;        /* owner of credentials */
        unsigned int capabilities;
-       char serverName[SERVER_NAME_LEN_WITH_NULL * 2]; /* BB make bigger for
-                               TCP names - will ipv6 and sctp addresses fit? */
+       char serverName[SERVER_NAME_LEN_WITH_NULL];
        char *user_name;        /* must not be null except during init of sess
                                   and after mount option parsing we fill it */
        char *domainName;

@@ -942,7 +941,9 @@ struct cifs_tcon {
        FILE_SYSTEM_DEVICE_INFO fsDevInfo;
        FILE_SYSTEM_ATTRIBUTE_INFO fsAttrInfo; /* ok if fs name truncated */
        FILE_SYSTEM_UNIX_INFO fsUnixInfo;
-       bool ipc:1;             /* set if connection to IPC$ eg for RPC/PIPES */
+       bool ipc:1;   /* set if connection to IPC$ share (always also pipe) */
+       bool pipe:1;  /* set if connection to pipe share */
+       bool print:1; /* set if connection to printer share */
        bool retry:1;
        bool nocase:1;
        bool seal:1;      /* transport encryption for this mounted share */

@@ -955,7 +956,6 @@ struct cifs_tcon {
        bool need_reopen_files:1; /* need to reopen tcon file handles */
        bool use_resilient:1; /* use resilient instead of durable handles */
        bool use_persistent:1; /* use persistent instead of durable handles */
-       bool print:1;           /* set if connection to printer share */
        __le32 capabilities;
        __u32 share_flags;
        __u32 maximal_access;

fs/cifs/cifssmb.c +4 -3

index 49cf999f3d46..4e0922d24eb2 100644
@@ -4833,10 +4833,11 @@ CIFSGetDFSRefer(const unsigned int xid, struct cifs_ses *ses,
        *target_nodes = NULL;
 
        cifs_dbg(FYI, "In GetDFSRefer the path %s\n", search_name);
-       if (ses == NULL)
+       if (ses == NULL || ses->tcon_ipc == NULL)
                return -ENODEV;
+
 getDFSRetry:
-       rc = smb_init(SMB_COM_TRANSACTION2, 15, NULL, (void **) &pSMB,
+       rc = smb_init(SMB_COM_TRANSACTION2, 15, ses->tcon_ipc, (void **) &pSMB,
                      (void **) &pSMBr);
        if (rc)
                return rc;

@@ -4844,7 +4845,7 @@ CIFSGetDFSRefer(const unsigned int xid, struct cifs_ses *ses,
        /* server pointer checked in called function,
        but should never be null here anyway */
        pSMB->hdr.Mid = get_next_mid(ses->server);
-       pSMB->hdr.Tid = ses->ipc_tid;
+       pSMB->hdr.Tid = ses->tcon_ipc->tid;
        pSMB->hdr.Uid = ses->Suid;
        if (ses->capabilities & CAP_STATUS32)
                pSMB->hdr.Flags2 |= SMBFLG2_ERR_STATUS;

fs/cifs/connect.c +113 -37

index 63c5d85fe25e..8b5e401f547a 100644
@@ -354,11 +354,12 @@ cifs_reconnect(struct TCP_Server_Info *server)
        list_for_each(tmp, &server->smb_ses_list) {
                ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
                ses->need_reconnect = true;
-               ses->ipc_tid = 0;
                list_for_each(tmp2, &ses->tcon_list) {
                        tcon = list_entry(tmp2, struct cifs_tcon, tcon_list);
                        tcon->need_reconnect = true;
                }
+               if (ses->tcon_ipc)
+                       ses->tcon_ipc->need_reconnect = true;
        }
        spin_unlock(&cifs_tcp_ses_lock);
 

@@ -2426,6 +2427,93 @@ static int match_session(struct cifs_ses *ses, struct smb_vol *vol)
        return 1;
 }
 
+/**
+ * cifs_setup_ipc - helper to setup the IPC tcon for the session
+ *
+ * A new IPC connection is made and stored in the session
+ * tcon_ipc. The IPC tcon has the same lifetime as the session.
+ */
+static int
+cifs_setup_ipc(struct cifs_ses *ses, struct smb_vol *volume_info)
+{
+       int rc = 0, xid;
+       struct cifs_tcon *tcon;
+       struct nls_table *nls_codepage;
+       char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
+       bool seal = false;
+
+       /*
+        * If the mount request that resulted in the creation of the
+        * session requires encryption, force IPC to be encrypted too.
+        */
+       if (volume_info->seal) {
+               if (ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
+                       seal = true;
+               else {
+                       cifs_dbg(VFS,
+                                "IPC: server doesn't support encryption\n");
+                       return -EOPNOTSUPP;
+               }
+       }
+
+       tcon = tconInfoAlloc();
+       if (tcon == NULL)
+               return -ENOMEM;
+
+       snprintf(unc, sizeof(unc), "\\\\%s\\IPC$", ses->serverName);
+
+       /* cannot fail */
+       nls_codepage = load_nls_default();
+
+       xid = get_xid();
+       tcon->ses = ses;
+       tcon->ipc = true;
+       tcon->seal = seal;
+       rc = ses->server->ops->tree_connect(xid, ses, unc, tcon, nls_codepage);
+       free_xid(xid);
+
+       if (rc) {
+               cifs_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
+               tconInfoFree(tcon);
+               goto out;
+       }
+
+       cifs_dbg(FYI, "IPC tcon rc = %d ipc tid = %d\n", rc, tcon->tid);
+
+       ses->tcon_ipc = tcon;
+out:
+       unload_nls(nls_codepage);
+       return rc;
+}
+
+/**
+ * cifs_free_ipc - helper to release the session IPC tcon
+ *
+ * Needs to be called everytime a session is destroyed
+ */
+static int
+cifs_free_ipc(struct cifs_ses *ses)
+{
+       int rc = 0, xid;
+       struct cifs_tcon *tcon = ses->tcon_ipc;
+
+       if (tcon == NULL)
+               return 0;
+
+       if (ses->server->ops->tree_disconnect) {
+               xid = get_xid();
+               rc = ses->server->ops->tree_disconnect(xid, tcon);
+               free_xid(xid);
+       }
+
+       if (rc)
+               cifs_dbg(FYI, "failed to disconnect IPC tcon (rc=%d)\n", rc);
+
+       tconInfoFree(tcon);
+       ses->tcon_ipc = NULL;
+       return rc;
+}
+
 static struct cifs_ses *
 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
 {

@@ -2466,6 +2554,8 @@ cifs_put_smb_ses(struct cifs_ses *ses)
                ses->status = CifsExiting;
        spin_unlock(&cifs_tcp_ses_lock);
 
+       cifs_free_ipc(ses);
+
        if (ses->status == CifsExiting && server->ops->logoff) {
                xid = get_xid();
                rc = server->ops->logoff(xid, ses);

@@ -2710,6 +2800,9 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
        spin_unlock(&cifs_tcp_ses_lock);
 
        free_xid(xid);
+
+       cifs_setup_ipc(ses, volume_info);
+
        return ses;
 
 get_ses_fail:

@@ -2754,8 +2847,16 @@ void
 cifs_put_tcon(struct cifs_tcon *tcon)
 {
        unsigned int xid;
-       struct cifs_ses *ses = tcon->ses;
+       struct cifs_ses *ses;
 
+       /*
+        * IPC tcon share the lifetime of their session and are
+        * destroyed in the session put function
+        */
+       if (tcon == NULL || tcon->ipc)
+               return;
+
+       ses = tcon->ses;
        cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
        spin_lock(&cifs_tcp_ses_lock);
        if (--tcon->tc_count > 0) {

@@ -3031,39 +3132,17 @@ get_dfs_path(const unsigned int xid, struct cifs_ses *ses, const char *old_path,
             const struct nls_table *nls_codepage, unsigned int *num_referrals,
             struct dfs_info3_param **referrals, int remap)
 {
-       char *temp_unc;
        int rc = 0;
 
-       if (!ses->server->ops->tree_connect || !ses->server->ops->get_dfs_refer)
+       if (!ses->server->ops->get_dfs_refer)
                return -ENOSYS;
 
        *num_referrals = 0;
        *referrals = NULL;
 
-       if (ses->ipc_tid == 0) {
-               temp_unc = kmalloc(2 /* for slashes */ +
-                       strnlen(ses->serverName, SERVER_NAME_LEN_WITH_NULL * 2)
-                               + 1 + 4 /* slash IPC$ */ + 2, GFP_KERNEL);
-               if (temp_unc == NULL)
-                       return -ENOMEM;
-               temp_unc[0] = '\\';
-               temp_unc[1] = '\\';
-               strcpy(temp_unc + 2, ses->serverName);
-               strcpy(temp_unc + 2 + strlen(ses->serverName), "\\IPC$");
-               rc = ses->server->ops->tree_connect(xid, ses, temp_unc, NULL,
-                                                   nls_codepage);
-               cifs_dbg(FYI, "Tcon rc = %d ipc_tid = %d\n", rc, ses->ipc_tid);
-               kfree(temp_unc);
-       }
-       if (rc == 0)
-               rc = ses->server->ops->get_dfs_refer(xid, ses, old_path,
-                                                    referrals, num_referrals,
-                                                    nls_codepage, remap);
-       /*
-        * BB - map targetUNCs to dfs_info3 structures, here or in
-        * ses->server->ops->get_dfs_refer.
-        */
-
+       rc = ses->server->ops->get_dfs_refer(xid, ses, old_path,
+                                            referrals, num_referrals,
+                                            nls_codepage, remap);
        return rc;
 }
 

@@ -3828,7 +3907,7 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
                tcon->unix_ext = 0; /* server does not support them */
 
        /* do not care if a following call succeed - informational */
-       if (!tcon->ipc && server->ops->qfs_tcon)
+       if (!tcon->pipe && server->ops->qfs_tcon)
                server->ops->qfs_tcon(xid, tcon);
 
        cifs_sb->wsize = server->ops->negotiate_wsize(tcon, volume_info);

@@ -3958,8 +4037,7 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 }
 
 /*
- * Issue a TREE_CONNECT request. Note that for IPC$ shares, that the tcon
- * pointer may be NULL.
+ * Issue a TREE_CONNECT request.
  */
 int
 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,

@@ -3995,7 +4073,7 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
        pSMB->AndXCommand = 0xFF;
        pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
        bcc_ptr = &pSMB->Password[0];
-       if (!tcon || (ses->server->sec_mode & SECMODE_USER)) {
+       if (tcon->pipe || (ses->server->sec_mode & SECMODE_USER)) {
                pSMB->PasswordLength = cpu_to_le16(1);  /* minimum */
                *bcc_ptr = 0; /* password is null byte */
                bcc_ptr++;              /* skip password */

@@ -4067,7 +4145,7 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                         0);
 
        /* above now done in SendReceive */
-       if ((rc == 0) && (tcon != NULL)) {
+       if (rc == 0) {
                bool is_unicode;
 
                tcon->tidStatus = CifsGood;

@@ -4087,7 +4165,8 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                        if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
                            (bcc_ptr[2] == 'C')) {
                                cifs_dbg(FYI, "IPC connection\n");
-                               tcon->ipc = 1;
+                               tcon->ipc = true;
+                               tcon->pipe = true;
                        }
                } else if (length == 2) {
                        if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {

@@ -4114,9 +4193,6 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
                else
                        tcon->Flags = 0;
                cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
-       } else if ((rc == 0) && tcon == NULL) {
-               /* all we need to save for IPC$ connection */
-               ses->ipc_tid = smb_buffer_response->Tid;
        }
 
        cifs_buf_release(smb_buffer);

fs/cifs/inode.c +1 -1

index ecb99079363a..8f9a8cc7cc62 100644
@@ -1049,7 +1049,7 @@ struct inode *cifs_root_iget(struct super_block *sb)
        tcon->resource_id = CIFS_I(inode)->uniqueid;
 #endif
 
-       if (rc && tcon->ipc) {
+       if (rc && tcon->pipe) {
                cifs_dbg(FYI, "ipc connection - fake read inode\n");
                spin_lock(&inode->i_lock);
                inode->i_mode |= S_IFDIR;

fs/cifs/smb2pdu.c +8 -29

index 7900aec7f92f..2943adc754e4 100644
@@ -1258,8 +1258,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
        }
 
        /* SMB2 TREE_CONNECT request must be called with TreeId == 0 */
-       if (tcon)
-               tcon->tid = 0;
+       tcon->tid = 0;
 
        rc = smb2_plain_req_init(SMB2_TREE_CONNECT, tcon, (void **) &req,
                             &total_len);

@@ -1268,15 +1267,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
                return rc;
        }
 
-       if (tcon == NULL) {
-               if ((ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA))
-                       flags |= CIFS_TRANSFORM_REQ;
-
-               /* since no tcon, smb2_init can not do this, so do here */
-               req->sync_hdr.SessionId = ses->Suid;
-               if (ses->server->sign)
-                       req->sync_hdr.Flags |= SMB2_FLAGS_SIGNED;
-       } else if (encryption_required(tcon))
+       if (encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;
 
        iov[0].iov_base = (char *)req;

@@ -1302,21 +1293,16 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
                goto tcon_error_exit;
        }
 
-       if (tcon == NULL) {
-               ses->ipc_tid = rsp->hdr.sync_hdr.TreeId;
-               goto tcon_exit;
-       }
-
        switch (rsp->ShareType) {
        case SMB2_SHARE_TYPE_DISK:
                cifs_dbg(FYI, "connection to disk share\n");
                break;
        case SMB2_SHARE_TYPE_PIPE:
-               tcon->ipc = true;
+               tcon->pipe = true;
                cifs_dbg(FYI, "connection to pipe share\n");
                break;
        case SMB2_SHARE_TYPE_PRINT:
-               tcon->ipc = true;
+               tcon->print = true;
                cifs_dbg(FYI, "connection to printer\n");
                break;
        default:

@@ -1892,16 +1878,6 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
        if (rc)
                return rc;
 
-       if (use_ipc) {
-               if (ses->ipc_tid == 0) {
-                       cifs_small_buf_release(req);
-                       return -ENOTCONN;
-               }
-
-               cifs_dbg(FYI, "replacing tid 0x%x with IPC tid 0x%x\n",
-                        req->sync_hdr.TreeId, ses->ipc_tid);
-               req->sync_hdr.TreeId = ses->ipc_tid;
-       }
        if (encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;
 

@@ -2317,6 +2293,10 @@ void smb2_reconnect_server(struct work_struct *work)
                                tcon_exist = true;
                        }
                }
+               if (ses->tcon_ipc && ses->tcon_ipc->need_reconnect) {
+                       list_add_tail(&ses->tcon_ipc->rlist, &tmp_list);
+                       tcon_exist = true;
+               }
        }
        /*
         * Get the reference to server struct to be sure that the last call of
--

2.12.3

--
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Since IPC now has a tcon object, the caller can just pass it. This allows domain-based DFS requests to work with smb2+.

Link https://bugzilla.samba.org/show_bug.cgi?id=12917

Fixes 9d49640a21bf ("CIFS: implement get_dfs_refer for SMB2+")

Signed-off-by Aurelien Aptel <aaptel-IBi9RG/[email protected]>

---
 fs/cifs/smb2file.c  |  2 +-
 fs/cifs/smb2ops.c   | 53 ++++++++++++++++++++++-------------------------------
 fs/cifs/smb2pdu.c   |  4 +---
 fs/cifs/smb2proto.h |  3 +--
 4 files changed, 25 insertions(+), 37 deletions(-)

fs/cifs/smb2file.c +1 -1

index b4b1f0305f29..12af5dba742b 100644
@@ -74,7 +74,7 @@ smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
                nr_ioctl_req.Reserved = 0;
                rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
                        fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        (char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
                        NULL, NULL /* no return info */);
                if (rc == -EOPNOTSUPP) {

fs/cifs/smb2ops.c +22 -31

index e3393ff5d458..eb68e2fcc500 100644
@@ -293,7 +293,6 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon)
 
        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                        FSCTL_QUERY_NETWORK_INTERFACE_INFO, true /* is_fsctl */,
-                       false /* use_ipc */,
                        NULL /* no data input */, 0 /* no data input */,
                        (char **)&out_buf, &ret_data_len);
        if (rc != 0)

@@ -792,7 +791,6 @@ SMB2_request_res_key(const unsigned int xid, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, persistent_fid, volatile_fid,
                        FSCTL_SRV_REQUEST_RESUME_KEY, true /* is_fsctl */,
-                       false /* use_ipc */,
                        NULL, 0 /* no input */,
                        (char **)&res_key, &ret_data_len);
 

@@ -858,8 +856,7 @@ smb2_copychunk_range(const unsigned int xid,
                /* Request server copy to target from src identified by key */
                rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid, FSCTL_SRV_COPYCHUNK_WRITE,
-                       true /* is_fsctl */, false /* use_ipc */,
-                       (char *)pcchunk,
+                       true /* is_fsctl */, (char *)pcchunk,
                        sizeof(struct copychunk_ioctl), (char **)&retbuf,
                        &ret_data_len);
                if (rc == 0) {

@@ -1020,7 +1017,7 @@ static bool smb2_set_sparse(const unsigned int xid, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_SPARSE,
-                       true /* is_fctl */, false /* use_ipc */,
+                       true /* is_fctl */,
                        &setsparse, 1, NULL, NULL);
        if (rc) {
                tcon->broken_sparse_sup = true;

@@ -1091,7 +1088,7 @@ smb2_duplicate_extents(const unsigned int xid,
        rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid,
                        FSCTL_DUPLICATE_EXTENTS_TO_FILE,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        (char *)&dup_ext_buf,
                        sizeof(struct duplicate_extents_to_file),
                        NULL,

@@ -1126,7 +1123,7 @@ smb3_set_integrity(const unsigned int xid, struct cifs_tcon *tcon,
        return SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid,
                        FSCTL_SET_INTEGRITY_INFORMATION,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        (char *)&integr_info,
                        sizeof(struct fsctl_set_integrity_information_req),
                        NULL,

@@ -1146,7 +1143,7 @@ smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid,
                        FSCTL_SRV_ENUMERATE_SNAPSHOTS,
-                       true /* is_fsctl */, false /* use_ipc */,
+                       true /* is_fsctl */,
                        NULL, 0 /* no input data */,
                        (char **)&retbuf,
                        &ret_data_len);

@@ -1365,16 +1362,20 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
        cifs_dbg(FYI, "smb2_get_dfs_refer path <%s>\n", search_name);
 
        /*
-        * Use any tcon from the current session. Here, the first one.
+        * Try to use the IPC tcon, otherwise just use any
         */
-       spin_lock(&cifs_tcp_ses_lock);
-       tcon = list_first_entry_or_null(&ses->tcon_list, struct cifs_tcon,
-                                       tcon_list);
-       if (tcon)
-               tcon->tc_count++;
-       spin_unlock(&cifs_tcp_ses_lock);
+       tcon = ses->tcon_ipc;
+       if (tcon == NULL) {
+               spin_lock(&cifs_tcp_ses_lock);
+               tcon = list_first_entry_or_null(&ses->tcon_list,
+                                               struct cifs_tcon,
+                                               tcon_list);
+               if (tcon)
+                       tcon->tc_count++;
+               spin_unlock(&cifs_tcp_ses_lock);
+       }
 
-       if (!tcon) {
+       if (tcon == NULL) {
                cifs_dbg(VFS, "session %p has no tcon available for a dfs referral request\n",
                         ses);
                rc = -ENOTCONN;

@@ -1403,20 +1404,11 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
        memcpy(dfs_req->RequestFileName, utf16_path, utf16_path_len);
 
        do {
-               /* try first with IPC */
                rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                                FSCTL_DFS_GET_REFERRALS,
-                               true /* is_fsctl */, true /* use_ipc */,
+                               true /* is_fsctl */,
                                (char *)dfs_req, dfs_req_size,
                                (char **)&dfs_rsp, &dfs_rsp_size);
-               if (rc == -ENOTCONN) {
-                       /* try with normal tcon */
-                       rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
-                                       FSCTL_DFS_GET_REFERRALS,
-                                       true /* is_fsctl */, false /*use_ipc*/,
-                                       (char *)dfs_req, dfs_req_size,
-                                       (char **)&dfs_rsp, &dfs_rsp_size);
-               }
        } while (rc == -EAGAIN);
 
        if (rc) {

@@ -1435,7 +1427,8 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
        }
 
  out:
-       if (tcon) {
+       if (tcon && !tcon->ipc) {
+               /* ipc tcons are not refcounted */
                spin_lock(&cifs_tcp_ses_lock);
                tcon->tc_count--;
                spin_unlock(&cifs_tcp_ses_lock);

@@ -1727,8 +1720,7 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,
-                       true /* is_fctl */, false /* use_ipc */,
-                       (char *)&fsctl_buf,
+                       true /* is_fctl */, (char *)&fsctl_buf,
                        sizeof(struct file_zero_data_information), NULL, NULL);
        free_xid(xid);
        return rc;

@@ -1762,8 +1754,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,
-                       true /* is_fctl */, false /* use_ipc */,
-                       (char *)&fsctl_buf,
+                       true /* is_fctl */, (char *)&fsctl_buf,
                        sizeof(struct file_zero_data_information), NULL, NULL);
        free_xid(xid);
        return rc;

fs/cifs/smb2pdu.c +1 -3

index 2943adc754e4..17b7f3aed195 100644
@@ -680,7 +680,6 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 
        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
-               false /* use_ipc */,
                (char *)&vneg_inbuf, sizeof(struct validate_negotiate_info_req),
                (char **)&pneg_rsp, &rsplen);
 

@@ -1841,7 +1840,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
  */
 int
 SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
-          u64 volatile_fid, u32 opcode, bool is_fsctl, bool use_ipc,
+          u64 volatile_fid, u32 opcode, bool is_fsctl,
           char *in_data, u32 indatalen,
           char **out_data, u32 *plen /* returned data len */)
 {

@@ -2006,7 +2005,6 @@ SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
 
        rc = SMB2_ioctl(xid, tcon, persistent_fid, volatile_fid,
                        FSCTL_SET_COMPRESSION, true /* is_fsctl */,
-                       false /* use_ipc */,
                        (char *)&fsctl_input /* data input */,
                        2 /* in data len */, &ret_data /* out data */, NULL);
 

fs/cifs/smb2proto.h +1 -3

index e9ab5227e7a8..05287b01f596 100644
@@ -125,8 +125,7 @@ extern int SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms,
                     struct smb2_err_rsp **err_buf);
 extern int SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon,
                     u64 persistent_fid, u64 volatile_fid, u32 opcode,
-                    bool is_fsctl, bool use_ipc,
-                    char *in_data, u32 indatalen,
+                    bool is_fsctl, char *in_data, u32 indatalen,
                     char **out_data, u32 *plen /* returned data len */);
 extern int SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
                      u64 persistent_file_id, u64 volatile_file_id);
--

2.12.3

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dump it as first share with an "IPC: " prefix.

Signed-off-by Aurelien Aptel <aaptel-IBi9RG/[email protected]>

---
 fs/cifs/cifs_debug.c | 61 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 35 insertions(+), 26 deletions(-)

fs/cifs/cifs_debug.c +35 -27

index 05be9b47eb0c..f491340f32ad 100644
@@ -110,6 +110,32 @@ void cifs_dump_mids(struct TCP_Server_Info *server)
 }
 
 #ifdef CONFIG_PROC_FS
+static void cifs_debug_tcon(struct seq_file *m, struct cifs_tcon *tcon)
+{
+       __u32 dev_type = le32_to_cpu(tcon->fsDevInfo.DeviceType);
+
+       seq_printf(m, "%s Mounts: %d ", tcon->treeName, tcon->tc_count);
+       if (tcon->nativeFileSystem)
+               seq_printf(m, "Type: %s ", tcon->nativeFileSystem);
+       seq_printf(m, "DevInfo: 0x%x Attributes: 0x%x\n\tPathComponentMax: %d Status: %d",
+                  le32_to_cpu(tcon->fsDevInfo.DeviceCharacteristics),
+                  le32_to_cpu(tcon->fsAttrInfo.Attributes),
+                  le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength),
+                  tcon->tidStatus);
+       if (dev_type == FILE_DEVICE_DISK)
+               seq_puts(m, " type: DISK ");
+       else if (dev_type == FILE_DEVICE_CD_ROM)
+               seq_puts(m, " type: CDROM ");
+       else
+               seq_printf(m, " type: %d ", dev_type);
+       if (tcon->ses->server->ops->dump_share_caps)
+               tcon->ses->server->ops->dump_share_caps(m, tcon);
+
+       if (tcon->need_reconnect)
+               seq_puts(m, "\tDISCONNECTED ");
+       seq_putc(m, '\n');
+}
+
 static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 {
        struct list_head *tmp1, *tmp2, *tmp3;

@@ -118,7 +144,6 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
        struct cifs_ses *ses;
        struct cifs_tcon *tcon;
        int i, j;
-       __u32 dev_type;
 
        seq_puts(m,
                    "Display Internal CIFS Data Structures for Debugging\n"

@@ -260,35 +285,19 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 
                        seq_puts(m, "\n\tShares:");
                        j = 0;
+
+                       seq_printf(m, "\n\t%d) IPC: ", j);
+                       if (ses->tcon_ipc)
+                               cifs_debug_tcon(m, ses->tcon_ipc);
+                       else
+                               seq_puts(m, "none\n");
+
                        list_for_each(tmp3, &ses->tcon_list) {
                                tcon = list_entry(tmp3, struct cifs_tcon,
                                                  tcon_list);
                                ++j;
-                               dev_type = le32_to_cpu(tcon->fsDevInfo.DeviceType);
-                               seq_printf(m, "\n\t%d) %s Mounts: %d ", j,
-                                          tcon->treeName, tcon->tc_count);
-                               if (tcon->nativeFileSystem) {
-                                       seq_printf(m, "Type: %s ",
-                                                  tcon->nativeFileSystem);
-                               }
-                               seq_printf(m, "DevInfo: 0x%x Attributes: 0x%x"
-                                       "\n\tPathComponentMax: %d Status: %d",
-                                       le32_to_cpu(tcon->fsDevInfo.DeviceCharacteristics),
-                                       le32_to_cpu(tcon->fsAttrInfo.Attributes),
-                                       le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength),
-                                       tcon->tidStatus);
-                               if (dev_type == FILE_DEVICE_DISK)
-                                       seq_puts(m, " type: DISK ");
-                               else if (dev_type == FILE_DEVICE_CD_ROM)
-                                       seq_puts(m, " type: CDROM ");
-                               else
-                                       seq_printf(m, " type: %d ", dev_type);
-                               if (server->ops->dump_share_caps)
-                                       server->ops->dump_share_caps(m, tcon);
-
-                               if (tcon->need_reconnect)
-                                       seq_puts(m, "\tDISCONNECTED ");
-                               seq_putc(m, '\n');
+                               seq_printf(m, "\n\t%d) ", j);
+                               cifs_debug_tcon(m, tcon);
                        }
 
                        seq_puts(m, "\n\tMIDs:\n");
--

2.12.3

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