[PATCH 6.1 0995/1067] cifs: Fix reacquisition of volume cookie on still-live connection

[PATCH 6.1 0995/1067] cifs: Fix reacquisition of volume cookie on still-live connection

[Greg Kroah-Hartman]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit dad80c6bff770d25f67ec25fe011730e4a463008 ]

During mount, cifs_mount_get_tcon() gets a tcon resource connection record
and then attaches an fscache volume cookie to it.  However, it does this
irrespective of whether or not the tcon returned from cifs_get_tcon() is a
new record or one that's already in use.  This leads to a warning about a
volume cookie collision and a leaked volume cookie because tcon->fscache
gets reset.

Fix this be adding a mutex and a "we've already tried this" flag and only
doing it once for the lifetime of the tcon.

[!] Note: Looking at cifs_mount_get_tcon(), a more general solution may
actually be required.  Reacquiring the volume cookie isn't the only thing
that function does: it also partially reinitialises the tcon record without
any locking - which may cause live filesystem ops already using the tcon
through a previous mount to malfunction.

This can be reproduced simply by something like:

    mount //example.com/test /xfstest.test -o user=shares,pass=xxx,fsc
    mount //example.com/test /mnt -o user=shares,pass=xxx,fsc

Fixes: 70431bfd825d ("cifs: Support fscache indexing rewrite")
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: ec457f9afe5a ("smb: client: resolve SWN tcon from live registrations")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/client/cifsglob.h |    2 ++
 fs/smb/client/fscache.c  |   13 +++++++++++++
 fs/smb/client/misc.c     |    3 +++
 3 files changed, 18 insertions(+)

--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1205,7 +1205,9 @@ struct cifs_tcon {
 	__u32 max_bytes_copy;
 #ifdef CONFIG_CIFS_FSCACHE
 	u64 resource_id;		/* server resource id */
+	bool fscache_acquired;		/* T if we've tried acquiring a cookie */
 	struct fscache_volume *fscache;	/* cookie for share */
+	struct mutex fscache_lock;	/* Prevent regetting a cookie */
 #endif
 	struct list_head pending_opens;	/* list of incomplete opens */
 	struct cached_fids *cfids;
--- a/fs/smb/client/fscache.c
+++ b/fs/smb/client/fscache.c
@@ -43,12 +43,23 @@ int cifs_fscache_get_super_cookie(struct
 	char *key;
 	int ret = -ENOMEM;
 
+	if (tcon->fscache_acquired)
+		return 0;
+
+	mutex_lock(&tcon->fscache_lock);
+	if (tcon->fscache_acquired) {
+		mutex_unlock(&tcon->fscache_lock);
+		return 0;
+	}
+	tcon->fscache_acquired = true;
+
 	tcon->fscache = NULL;
 	switch (sa->sa_family) {
 	case AF_INET:
 	case AF_INET6:
 		break;
 	default:
+		mutex_unlock(&tcon->fscache_lock);
 		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
 		return -EINVAL;
 	}
@@ -57,6 +68,7 @@ int cifs_fscache_get_super_cookie(struct
 
 	sharename = extract_sharename(tcon->tree_name);
 	if (IS_ERR(sharename)) {
+		mutex_unlock(&tcon->fscache_lock);
 		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
 		return PTR_ERR(sharename);
 	}
@@ -90,6 +102,7 @@ out_2:
 	kfree(key);
 out:
 	kfree(sharename);
+	mutex_unlock(&tcon->fscache_lock);
 	return ret;
 }
 
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -139,6 +139,9 @@ tconInfoAlloc(void)
 	spin_lock_init(&ret_buf->stat_lock);
 	atomic_set(&ret_buf->num_local_opens, 0);
 	atomic_set(&ret_buf->num_remote_opens, 0);
+#ifdef CONFIG_CIFS_FSCACHE
+	mutex_init(&ret_buf->fscache_lock);
+#endif
 
 	return ret_buf;
 }

[PATCH 6.1 0996/1067] cifs: Add tracing for the cifs_tcon struct refcounting

[Greg Kroah-Hartman]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit afc23febd51c7e24361e3a9c09f3e892eb0a41ea ]

Add tracing for the refcounting/lifecycle of the cifs_tcon struct, marking
different events with different labels and giving each tcon its own debug
ID so that the tracelines corresponding to individual tcons can be
distinguished.  This can be enabled with:

	echo 1 >/sys/kernel/debug/tracing/events/cifs/smb3_tcon_ref/enable

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: ec457f9afe5a ("smb: client: resolve SWN tcon from live registrations")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/client/cifs_swn.c      |   13 ++---
 fs/smb/client/cifsfs.c        |    2 
 fs/smb/client/cifsglob.h      |    1 
 fs/smb/client/cifsproto.h     |    8 +--
 fs/smb/client/connect.c       |   21 +++++----
 fs/smb/client/dfs_cache.c     |    2 
 fs/smb/client/fscache.c       |    7 +++
 fs/smb/client/misc.c          |   12 +++--
 fs/smb/client/smb2misc.c      |   10 +++-
 fs/smb/client/smb2ops.c       |    7 ++-
 fs/smb/client/smb2pdu.c       |    8 ++-
 fs/smb/client/smb2transport.c |    2 
 fs/smb/client/trace.h         |   93 +++++++++++++++++++++++++++++++++++++++++-
 13 files changed, 151 insertions(+), 35 deletions(-)

--- a/fs/smb/client/cifs_swn.c
+++ b/fs/smb/client/cifs_swn.c
@@ -313,17 +313,15 @@ static struct cifs_swn_reg *cifs_get_swn
 	reg = cifs_find_swn_reg(tcon);
 	if (!IS_ERR(reg)) {
 		kref_get(&reg->ref_count);
-		mutex_unlock(&cifs_swnreg_idr_mutex);
-		return reg;
+		goto unlock;
 	} else if (PTR_ERR(reg) != -EEXIST) {
-		mutex_unlock(&cifs_swnreg_idr_mutex);
-		return reg;
+		goto unlock;
 	}
 
 	reg = kmalloc(sizeof(struct cifs_swn_reg), GFP_ATOMIC);
 	if (reg == NULL) {
-		mutex_unlock(&cifs_swnreg_idr_mutex);
-		return ERR_PTR(-ENOMEM);
+		ret = -ENOMEM;
+		goto fail_unlock;
 	}
 
 	kref_init(&reg->ref_count);
@@ -354,7 +352,7 @@ static struct cifs_swn_reg *cifs_get_swn
 	reg->ip_notify = (tcon->capabilities & SMB2_SHARE_CAP_SCALEOUT);
 
 	reg->tcon = tcon;
-
+unlock:
 	mutex_unlock(&cifs_swnreg_idr_mutex);
 
 	return reg;
@@ -365,6 +363,7 @@ fail_idr:
 	idr_remove(&cifs_swnreg_idr, reg->id);
 fail:
 	kfree(reg);
+fail_unlock:
 	mutex_unlock(&cifs_swnreg_idr_mutex);
 	return ERR_PTR(ret);
 }
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -747,6 +747,8 @@ static void cifs_umount_begin(struct sup
 
 	spin_lock(&cifs_tcp_ses_lock);
 	spin_lock(&tcon->tc_lock);
+	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+			    netfs_trace_tcon_ref_see_umount);
 	if ((tcon->tc_count > 1) || (tcon->status == TID_EXITING)) {
 		/* we have other mounts to same share or we have
 		   already tried to umount this and woken up
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1121,6 +1121,7 @@ struct cifs_fattr {
  */
 struct cifs_tcon {
 	struct list_head tcon_list;
+	int debug_id;		/* Debugging for tracing */
 	int tc_count;
 	struct list_head rlist; /* reconnect list */
 	spinlock_t tc_lock;  /* protect anything here that is not protected */
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -305,7 +305,7 @@ cifs_get_tcp_session(struct smb3_fs_cont
 		     struct TCP_Server_Info *primary_server);
 extern void cifs_put_tcp_session(struct TCP_Server_Info *server,
 				 int from_reconnect);
-extern void cifs_put_tcon(struct cifs_tcon *tcon);
+extern void cifs_put_tcon(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace);
 
 #if IS_ENABLED(CONFIG_CIFS_DFS_UPCALL)
 extern void cifs_dfs_release_automount_timer(void);
@@ -525,8 +525,8 @@ extern int CIFSSMBLogoff(const unsigned
 
 extern struct cifs_ses *sesInfoAlloc(void);
 extern void sesInfoFree(struct cifs_ses *);
-extern struct cifs_tcon *tconInfoAlloc(void);
-extern void tconInfoFree(struct cifs_tcon *);
+extern struct cifs_tcon *tconInfoAlloc(enum smb3_tcon_ref_trace trace);
+extern void tconInfoFree(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace);
 
 extern int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
 		   __u32 *pexpected_response_sequence_number);
@@ -719,8 +719,6 @@ static inline int cifs_create_options(st
 		return options;
 }
 
-struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon);
-void cifs_put_tcon_super(struct super_block *sb);
 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry);
 
 static inline void release_mid(struct mid_q_entry *mid)
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -1985,7 +1985,7 @@ cifs_setup_ipc(struct cifs_ses *ses, str
 		}
 	}
 
-	tcon = tconInfoAlloc();
+	tcon = tconInfoAlloc(netfs_trace_tcon_ref_new_ipc);
 	if (tcon == NULL)
 		return -ENOMEM;
 
@@ -2002,7 +2002,7 @@ cifs_setup_ipc(struct cifs_ses *ses, str
 
 	if (rc) {
 		cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
-		tconInfoFree(tcon);
+		tconInfoFree(tcon, netfs_trace_tcon_ref_free_ipc_fail);
 		goto out;
 	}
 
@@ -2085,7 +2085,7 @@ void cifs_put_smb_ses(struct cifs_ses *s
 	 * files on session close, as specified in MS-SMB2 3.3.5.6 Receiving an
 	 * SMB2 LOGOFF Request.
 	 */
-	tconInfoFree(tcon);
+	tconInfoFree(tcon, netfs_trace_tcon_ref_free_ipc);
 	if (do_logoff) {
 		xid = get_xid();
 		rc = server->ops->logoff(xid, ses);
@@ -2459,6 +2459,8 @@ cifs_find_tcon(struct cifs_ses *ses, str
 			continue;
 		}
 		++tcon->tc_count;
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_get_find);
 		spin_unlock(&tcon->tc_lock);
 		spin_unlock(&cifs_tcp_ses_lock);
 		return tcon;
@@ -2468,7 +2470,7 @@ cifs_find_tcon(struct cifs_ses *ses, str
 }
 
 void
-cifs_put_tcon(struct cifs_tcon *tcon)
+cifs_put_tcon(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 {
 	unsigned int xid;
 	struct cifs_ses *ses;
@@ -2484,6 +2486,7 @@ cifs_put_tcon(struct cifs_tcon *tcon)
 	cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
 	spin_lock(&cifs_tcp_ses_lock);
 	spin_lock(&tcon->tc_lock);
+	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count - 1, trace);
 	if (--tcon->tc_count > 0) {
 		spin_unlock(&tcon->tc_lock);
 		spin_unlock(&cifs_tcp_ses_lock);
@@ -2517,7 +2520,7 @@ cifs_put_tcon(struct cifs_tcon *tcon)
 	_free_xid(xid);
 
 	cifs_fscache_release_super_cookie(tcon);
-	tconInfoFree(tcon);
+	tconInfoFree(tcon, netfs_trace_tcon_ref_free);
 	cifs_put_smb_ses(ses);
 }
 
@@ -2565,7 +2568,7 @@ cifs_get_tcon(struct cifs_ses *ses, stru
 		goto out_fail;
 	}
 
-	tcon = tconInfoAlloc();
+	tcon = tconInfoAlloc(netfs_trace_tcon_ref_new);
 	if (tcon == NULL) {
 		rc = -ENOMEM;
 		goto out_fail;
@@ -2762,7 +2765,7 @@ cifs_get_tcon(struct cifs_ses *ses, stru
 	return tcon;
 
 out_fail:
-	tconInfoFree(tcon);
+	tconInfoFree(tcon, netfs_trace_tcon_ref_free_fail);
 	return ERR_PTR(rc);
 }
 
@@ -2779,7 +2782,7 @@ cifs_put_tlink(struct tcon_link *tlink)
 	}
 
 	if (!IS_ERR(tlink_tcon(tlink)))
-		cifs_put_tcon(tlink_tcon(tlink));
+		cifs_put_tcon(tlink_tcon(tlink), netfs_trace_tcon_ref_put_tlink);
 	kfree(tlink);
 	return;
 }
@@ -3338,7 +3341,7 @@ static inline void mount_put_conns(struc
 	int rc = 0;
 
 	if (mnt_ctx->tcon)
-		cifs_put_tcon(mnt_ctx->tcon);
+		cifs_put_tcon(mnt_ctx->tcon, netfs_trace_tcon_ref_put_mnt_ctx);
 	else if (mnt_ctx->ses)
 		cifs_put_smb_ses(mnt_ctx->ses);
 	else if (mnt_ctx->server)
--- a/fs/smb/client/dfs_cache.c
+++ b/fs/smb/client/dfs_cache.c
@@ -1564,7 +1564,7 @@ static void refresh_mounts(struct cifs_s
 		}
 		mutex_unlock(&server->refpath_lock);
 
-		cifs_put_tcon(tcon);
+		cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_dfs_refer);
 	}
 }
 
--- a/fs/smb/client/fscache.c
+++ b/fs/smb/client/fscache.c
@@ -94,6 +94,11 @@ int cifs_fscache_get_super_cookie(struct
 		}
 		pr_err("Cache volume key already in use (%s)\n", key);
 		vcookie = NULL;
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_see_fscache_collision);
+	} else {
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_see_fscache_okay);
 	}
 
 	tcon->fscache = vcookie;
@@ -115,6 +120,8 @@ void cifs_fscache_release_super_cookie(s
 	cifs_fscache_fill_volume_coherency(tcon, &cd);
 	fscache_relinquish_volume(tcon->fscache, &cd, false);
 	tcon->fscache = NULL;
+	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+			    netfs_trace_tcon_ref_see_fscache_relinq);
 }
 
 void cifs_fscache_get_inode_cookie(struct inode *inode)
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -116,9 +116,10 @@ sesInfoFree(struct cifs_ses *buf_to_free
 }
 
 struct cifs_tcon *
-tconInfoAlloc(void)
+tconInfoAlloc(enum smb3_tcon_ref_trace trace)
 {
 	struct cifs_tcon *ret_buf;
+	static atomic_t tcon_debug_id;
 
 	ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 	if (!ret_buf)
@@ -131,7 +132,8 @@ tconInfoAlloc(void)
 
 	atomic_inc(&tconInfoAllocCount);
 	ret_buf->status = TID_NEW;
-	++ret_buf->tc_count;
+	ret_buf->debug_id = atomic_inc_return(&tcon_debug_id);
+	ret_buf->tc_count = 1;
 	spin_lock_init(&ret_buf->tc_lock);
 	INIT_LIST_HEAD(&ret_buf->openFileList);
 	INIT_LIST_HEAD(&ret_buf->tcon_list);
@@ -142,17 +144,19 @@ tconInfoAlloc(void)
 #ifdef CONFIG_CIFS_FSCACHE
 	mutex_init(&ret_buf->fscache_lock);
 #endif
+	trace_smb3_tcon_ref(ret_buf->debug_id, ret_buf->tc_count, trace);
 
 	return ret_buf;
 }
 
 void
-tconInfoFree(struct cifs_tcon *tcon)
+tconInfoFree(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 {
 	if (tcon == NULL) {
 		cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 		return;
 	}
+	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace);
 	free_cached_dirs(tcon->cfids);
 	atomic_dec(&tconInfoAllocCount);
 	kfree(tcon->nativeFileSystem);
@@ -848,7 +852,7 @@ void cifs_close_all_deferred_files_sb(st
 	list_for_each_entry_safe(tmp_list, q, &tcon_head, entry) {
 		cifs_close_all_deferred_files(tmp_list->tcon);
 		list_del(&tmp_list->entry);
-		cifs_put_tcon(tmp_list->tcon);
+		cifs_put_tcon(tmp_list->tcon, netfs_trace_tcon_ref_put_tlink);
 		kfree(tmp_list);
 	}
 }
--- a/fs/smb/client/smb2misc.c
+++ b/fs/smb/client/smb2misc.c
@@ -804,7 +804,7 @@ smb2_cancelled_close_fid(struct work_str
 	if (rc)
 		cifs_tcon_dbg(VFS, "Close cancelled mid failed rc:%d\n", rc);
 
-	cifs_put_tcon(tcon);
+	cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_cancelled_close_fid);
 	kfree(cancelled);
 }
 
@@ -848,6 +848,8 @@ smb2_handle_cancelled_close(struct cifs_
 	if (tcon->tc_count <= 0) {
 		struct TCP_Server_Info *server = NULL;
 
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_see_cancelled_close);
 		WARN_ONCE(tcon->tc_count < 0, "tcon refcount is negative");
 		spin_unlock(&cifs_tcp_ses_lock);
 
@@ -861,12 +863,14 @@ smb2_handle_cancelled_close(struct cifs_
 		return 0;
 	}
 	tcon->tc_count++;
+	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+			    netfs_trace_tcon_ref_get_cancelled_close);
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	rc = __smb2_handle_cancelled_cmd(tcon, SMB2_CLOSE_HE, 0,
 					 persistent_fid, volatile_fid);
 	if (rc)
-		cifs_put_tcon(tcon);
+		cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_cancelled_close);
 
 	return rc;
 }
@@ -894,7 +898,7 @@ smb2_handle_cancelled_mid(struct mid_q_e
 					 rsp->PersistentFileId,
 					 rsp->VolatileFileId);
 	if (rc)
-		cifs_put_tcon(tcon);
+		cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_cancelled_mid);
 
 	return rc;
 }
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -2848,8 +2848,11 @@ smb2_get_dfs_refer(const unsigned int xi
 		tcon = list_first_entry_or_null(&ses->tcon_list,
 						struct cifs_tcon,
 						tcon_list);
-		if (tcon)
+		if (tcon) {
 			tcon->tc_count++;
+			trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+					    netfs_trace_tcon_ref_get_dfs_refer);
+		}
 		spin_unlock(&cifs_tcp_ses_lock);
 	}
 
@@ -2913,6 +2916,8 @@ smb2_get_dfs_refer(const unsigned int xi
 		/* ipc tcons are not refcounted */
 		spin_lock(&cifs_tcp_ses_lock);
 		tcon->tc_count--;
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_dec_dfs_refer);
 		/* tc_count can never go negative */
 		WARN_ON(tcon->tc_count < 0);
 		spin_unlock(&cifs_tcp_ses_lock);
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -3995,6 +3995,8 @@ void smb2_reconnect_server(struct work_s
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			if (tcon->need_reconnect || tcon->need_reopen_files) {
 				tcon->tc_count++;
+				trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+						    netfs_trace_tcon_ref_get_reconnect_server);
 				list_add_tail(&tcon->rlist, &tmp_list);
 				tcon_selected = tcon_exist = true;
 			}
@@ -4040,14 +4042,14 @@ void smb2_reconnect_server(struct work_s
 		if (tcon->ipc)
 			cifs_put_smb_ses(tcon->ses);
 		else
-			cifs_put_tcon(tcon);
+			cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_reconnect_server);
 	}
 
 	if (!ses_exist)
 		goto done;
 
 	/* allocate a dummy tcon struct used for reconnect */
-	tcon = tconInfoAlloc();
+	tcon = tconInfoAlloc(netfs_trace_tcon_ref_new_reconnect_server);
 	if (!tcon) {
 		resched = true;
 		list_for_each_entry_safe(ses, ses2, &tmp_ses_list, rlist) {
@@ -4070,7 +4072,7 @@ void smb2_reconnect_server(struct work_s
 		list_del_init(&ses->rlist);
 		cifs_put_smb_ses(ses);
 	}
-	tconInfoFree(tcon);
+	tconInfoFree(tcon, netfs_trace_tcon_ref_free_reconnect_server);
 
 done:
 	cifs_dbg(FYI, "Reconnecting tcons and channels finished\n");
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -189,6 +189,8 @@ smb2_find_smb_sess_tcon_unlocked(struct
 		if (tcon->tid != tid)
 			continue;
 		++tcon->tc_count;
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_get_find_sess_tcon);
 		return tcon;
 	}
 
--- a/fs/smb/client/trace.h
+++ b/fs/smb/client/trace.h
@@ -3,6 +3,9 @@
  *   Copyright (C) 2018, Microsoft Corporation.
  *
  *   Author(s): Steve French <stfrench@microsoft.com>
+ *
+ * Please use this 3-part article as a reference for writing new tracepoints:
+ * https://lwn.net/Articles/379903/
  */
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM cifs
@@ -15,9 +18,71 @@
 #include <linux/inet.h>
 
 /*
- * Please use this 3-part article as a reference for writing new tracepoints:
- * https://lwn.net/Articles/379903/
+ * Specify enums for tracing information.
+ */
+#define smb3_tcon_ref_traces					      \
+	EM(netfs_trace_tcon_ref_dec_dfs_refer,		"DEC DfsRef") \
+	EM(netfs_trace_tcon_ref_free,			"FRE       ") \
+	EM(netfs_trace_tcon_ref_free_fail,		"FRE Fail  ") \
+	EM(netfs_trace_tcon_ref_free_ipc,		"FRE Ipc   ") \
+	EM(netfs_trace_tcon_ref_free_ipc_fail,		"FRE Ipc-F ") \
+	EM(netfs_trace_tcon_ref_free_reconnect_server,	"FRE Reconn") \
+	EM(netfs_trace_tcon_ref_get_cancelled_close,	"GET Cn-Cls") \
+	EM(netfs_trace_tcon_ref_get_dfs_refer,		"GET DfsRef") \
+	EM(netfs_trace_tcon_ref_get_find,		"GET Find  ") \
+	EM(netfs_trace_tcon_ref_get_find_sess_tcon,	"GET FndSes") \
+	EM(netfs_trace_tcon_ref_get_reconnect_server,	"GET Reconn") \
+	EM(netfs_trace_tcon_ref_new,			"NEW       ") \
+	EM(netfs_trace_tcon_ref_new_ipc,		"NEW Ipc   ") \
+	EM(netfs_trace_tcon_ref_new_reconnect_server,	"NEW Reconn") \
+	EM(netfs_trace_tcon_ref_put_cancelled_close,	"PUT Cn-Cls") \
+	EM(netfs_trace_tcon_ref_put_cancelled_close_fid, "PUT Cn-Fid") \
+	EM(netfs_trace_tcon_ref_put_cancelled_mid,	"PUT Cn-Mid") \
+	EM(netfs_trace_tcon_ref_put_mnt_ctx,		"PUT MntCtx") \
+	EM(netfs_trace_tcon_ref_put_dfs_refer,		"PUT DfsRfr") \
+	EM(netfs_trace_tcon_ref_put_reconnect_server,	"PUT Reconn") \
+	EM(netfs_trace_tcon_ref_put_tlink,		"PUT Tlink ") \
+	EM(netfs_trace_tcon_ref_see_cancelled_close,	"SEE Cn-Cls") \
+	EM(netfs_trace_tcon_ref_see_fscache_collision,	"SEE FV-CO!") \
+	EM(netfs_trace_tcon_ref_see_fscache_okay,	"SEE FV-Ok ") \
+	EM(netfs_trace_tcon_ref_see_fscache_relinq,	"SEE FV-Rlq") \
+	E_(netfs_trace_tcon_ref_see_umount,		"SEE Umount")
+
+#undef EM
+#undef E_
+
+/*
+ * Define those tracing enums.
  */
+#ifndef __SMB3_DECLARE_TRACE_ENUMS_ONCE_ONLY
+#define __SMB3_DECLARE_TRACE_ENUMS_ONCE_ONLY
+
+#define EM(a, b) a,
+#define E_(a, b) a
+
+enum smb3_tcon_ref_trace { smb3_tcon_ref_traces } __mode(byte);
+
+#undef EM
+#undef E_
+#endif
+
+/*
+ * Export enum symbols via userspace.
+ */
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define E_(a, b) TRACE_DEFINE_ENUM(a);
+
+smb3_tcon_ref_traces;
+
+#undef EM
+#undef E_
+
+/*
+ * Now redefine the EM() and E_() macros to map the enums to the strings that
+ * will be printed in the output.
+ */
+#define EM(a, b)	{ a, b },
+#define E_(a, b)	{ a, b }
 
 /* For logging errors in read or write */
 DECLARE_EVENT_CLASS(smb3_rw_err_class,
@@ -1062,6 +1127,30 @@ DEFINE_SMB3_CREDIT_EVENT(waitff_credits)
 DEFINE_SMB3_CREDIT_EVENT(overflow_credits);
 DEFINE_SMB3_CREDIT_EVENT(set_credits);
 
+
+TRACE_EVENT(smb3_tcon_ref,
+	    TP_PROTO(unsigned int tcon_debug_id, int ref,
+		     enum smb3_tcon_ref_trace trace),
+	    TP_ARGS(tcon_debug_id, ref, trace),
+	    TP_STRUCT__entry(
+		    __field(unsigned int,		tcon)
+		    __field(int,			ref)
+		    __field(enum smb3_tcon_ref_trace,	trace)
+			     ),
+	    TP_fast_assign(
+		    __entry->tcon	= tcon_debug_id;
+		    __entry->ref	= ref;
+		    __entry->trace	= trace;
+			   ),
+	    TP_printk("TC=%08x %s r=%u",
+		      __entry->tcon,
+		      __print_symbolic(__entry->trace, smb3_tcon_ref_traces),
+		      __entry->ref)
+	    );
+
+
+#undef EM
+#undef E_
 #endif /* _CIFS_TRACE_H */
 
 #undef TRACE_INCLUDE_PATH

[PATCH 6.1 1002/1067] ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc

[Greg Kroah-Hartman]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit ad0057fb91218914d6c98268718ceb9d59b388e1 ]

The kernel ASN.1 BER decoder calls action callbacks incrementally as it
walks the input.  When ksmbd_decode_negTokenInit() reaches the mechToken
[2] OCTET STRING element, ksmbd_neg_token_alloc() allocates
conn->mechToken immediately via kmemdup_nul().  If a later element in
the same blob is malformed, then the decoder will return nonzero after
the allocation is already live.  This could happen if mechListMIC [3]
overrunse the enclosing SEQUENCE.

decode_negotiation_token() then sets conn->use_spnego = false because
both the negTokenInit and negTokenTarg grammars failed.  The cleanup at
the bottom of smb2_sess_setup() is gated on use_spnego:

	if (conn->use_spnego && conn->mechToken) {
		kfree(conn->mechToken);
		conn->mechToken = NULL;
	}

so the kfree is skipped, causing the mechToken to never be freed.

This codepath is reachable pre-authentication, so untrusted clients can
cause slow memory leaks on a server without even being properly
authenticated.

Fix this up by not checking check for use_spnego, as it's not required,
so the memory will always be properly freed.  At the same time, always
free the memory in ksmbd_conn_free() incase some other failure path
forgot to free it.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: c1016dd1d8b2 ("ksmbd: track the connection owning a byte-range lock")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/server/connection.c |    1 +
 fs/smb/server/smb2pdu.c    |    2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

--- a/fs/smb/server/connection.c
+++ b/fs/smb/server/connection.c
@@ -39,6 +39,7 @@ void ksmbd_conn_free(struct ksmbd_conn *
 	xa_destroy(&conn->sessions);
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
+	kfree(conn->mechToken);
 	kfree(conn);
 }
 
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -1909,7 +1909,7 @@ out_err:
 	else if (rc)
 		rsp->hdr.Status = STATUS_LOGON_FAILURE;
 
-	if (conn->use_spnego && conn->mechToken) {
+	if (conn->mechToken) {
 		kfree(conn->mechToken);
 		conn->mechToken = NULL;
 	}