3 cifs/smb3 fixes, one for symlink handling and two fix multichannel issues with iterating channels, including for oplock breaks when leases are disabled

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Merge tag '6.1-rc4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "One symlink handling fix and two fixes foir multichannel issues with
  iterating channels, including for oplock breaks when leases are
  disabled"

* tag '6.1-rc4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix use-after-free on the link name
  cifs: avoid unnecessary iteration of tcp sessions
  cifs: always iterate smb sessions using primary channel

fs/cifs/cifsfs.c

@@ -1143,8 +1143,32 @@ const struct inode_operations cifs_file_inode_ops = {
 	.fiemap = cifs_fiemap,
 };
 
+const char *cifs_get_link(struct dentry *dentry, struct inode *inode,
+			    struct delayed_call *done)
+{
+	char *target_path;
+
+	target_path = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!target_path)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock(&inode->i_lock);
+	if (likely(CIFS_I(inode)->symlink_target)) {
+		strscpy(target_path, CIFS_I(inode)->symlink_target, PATH_MAX);
+	} else {
+		kfree(target_path);
+		target_path = ERR_PTR(-EOPNOTSUPP);
+	}
+	spin_unlock(&inode->i_lock);
+
+	if (!IS_ERR(target_path))
+		set_delayed_call(done, kfree_link, target_path);
+
+	return target_path;
+}
+
 const struct inode_operations cifs_symlink_inode_ops = {
-	.get_link = simple_get_link,
+	.get_link = cifs_get_link,
 	.permission = cifs_permission,
 	.listxattr = cifs_listxattr,
 };

fs/cifs/inode.c

@@ -215,11 +215,6 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
 		kfree(cifs_i->symlink_target);
 		cifs_i->symlink_target = fattr->cf_symlink_target;
 		fattr->cf_symlink_target = NULL;
-
-		if (unlikely(!cifs_i->symlink_target))
-			inode->i_link = ERR_PTR(-EOPNOTSUPP);
-		else
-			inode->i_link = cifs_i->symlink_target;
 	}
 	spin_unlock(&inode->i_lock);
 

fs/cifs/misc.c

@@ -400,6 +400,7 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 {
 	struct smb_hdr *buf = (struct smb_hdr *)buffer;
 	struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 	struct cifsInodeInfo *pCifsInode;
@@ -464,9 +465,12 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 		return false;
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
+
 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
-	list_for_each_entry(ses, &srv->smb_ses_list, smb_ses_list) {
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			if (tcon->tid != buf->Tid)
 				continue;

fs/cifs/smb2misc.c

@@ -135,6 +135,7 @@ static __u32 get_neg_ctxt_len(struct smb2_hdr *hdr, __u32 len,
 int
 smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *server)
 {
+	struct TCP_Server_Info *pserver;
 	struct smb2_hdr *shdr = (struct smb2_hdr *)buf;
 	struct smb2_pdu *pdu = (struct smb2_pdu *)shdr;
 	int hdr_size = sizeof(struct smb2_hdr);
@@ -143,6 +144,9 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *server)
 	__u32 calc_len; /* calculated length */
 	__u64 mid;
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
 	/*
 	 * Add function to do table lookup of StructureSize by command
 	 * ie Validate the wct via smb2_struct_sizes table above
@@ -155,7 +159,7 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *server)
 
 		/* decrypt frame now that it is completely read in */
 		spin_lock(&cifs_tcp_ses_lock);
-		list_for_each_entry(iter, &server->smb_ses_list, smb_ses_list) {
+		list_for_each_entry(iter, &pserver->smb_ses_list, smb_ses_list) {
 			if (iter->Suid == le64_to_cpu(thdr->SessionId)) {
 				ses = iter;
 				break;
@@ -608,51 +612,52 @@ smb2_tcon_find_pending_open_lease(struct cifs_tcon *tcon,
 }
 
 static bool
-smb2_is_valid_lease_break(char *buffer)
+smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 {
 	struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
-	struct TCP_Server_Info *server;
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 	struct cifs_pending_open *open;
 
 	cifs_dbg(FYI, "Checking for lease break\n");
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
-	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
-		list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
-			list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
+			spin_lock(&tcon->open_file_lock);
-				spin_lock(&tcon->open_file_lock);
+			cifs_stats_inc(
-				cifs_stats_inc(
+				       &tcon->stats.cifs_stats.num_oplock_brks);
-				    &tcon->stats.cifs_stats.num_oplock_brks);
+			if (smb2_tcon_has_lease(tcon, rsp)) {
-				if (smb2_tcon_has_lease(tcon, rsp)) {
-					spin_unlock(&tcon->open_file_lock);
-					spin_unlock(&cifs_tcp_ses_lock);
-					return true;
-				}
-				open = smb2_tcon_find_pending_open_lease(tcon,
-									 rsp);
-				if (open) {
-					__u8 lease_key[SMB2_LEASE_KEY_SIZE];
-					struct tcon_link *tlink;
-
-					tlink = cifs_get_tlink(open->tlink);
-					memcpy(lease_key, open->lease_key,
-					       SMB2_LEASE_KEY_SIZE);
-					spin_unlock(&tcon->open_file_lock);
-					spin_unlock(&cifs_tcp_ses_lock);
-					smb2_queue_pending_open_break(tlink,
-								      lease_key,
-								      rsp->NewLeaseState);
-					return true;
-				}
 				spin_unlock(&tcon->open_file_lock);
+				spin_unlock(&cifs_tcp_ses_lock);
+				return true;
+			}
+			open = smb2_tcon_find_pending_open_lease(tcon,
+								 rsp);
+			if (open) {
+				__u8 lease_key[SMB2_LEASE_KEY_SIZE];
+				struct tcon_link *tlink;
 
-				if (cached_dir_lease_break(tcon, rsp->LeaseKey)) {
+				tlink = cifs_get_tlink(open->tlink);
-					spin_unlock(&cifs_tcp_ses_lock);
+				memcpy(lease_key, open->lease_key,
-					return true;
+				       SMB2_LEASE_KEY_SIZE);
-				}
+				spin_unlock(&tcon->open_file_lock);
+				spin_unlock(&cifs_tcp_ses_lock);
+				smb2_queue_pending_open_break(tlink,
+							      lease_key,
+							      rsp->NewLeaseState);
+				return true;
+			}
+			spin_unlock(&tcon->open_file_lock);
+
+			if (cached_dir_lease_break(tcon, rsp->LeaseKey)) {
+				spin_unlock(&cifs_tcp_ses_lock);
+				return true;
 			}
 		}
 	}
@@ -671,6 +676,7 @@ bool
 smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 {
 	struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 	struct cifsInodeInfo *cinode;
@@ -684,16 +690,19 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 	if (rsp->StructureSize !=
 				smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 		if (le16_to_cpu(rsp->StructureSize) == 44)
-			return smb2_is_valid_lease_break(buffer);
+			return smb2_is_valid_lease_break(buffer, server);
 		else
 			return false;
 	}
 
 	cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
-	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 
 			spin_lock(&tcon->open_file_lock);

fs/cifs/smb2ops.c

@@ -2302,14 +2302,18 @@ static void
 smb2_is_network_name_deleted(char *buf, struct TCP_Server_Info *server)
 {
 	struct smb2_hdr *shdr = (struct smb2_hdr *)buf;
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 
 	if (shdr->Status != STATUS_NETWORK_NAME_DELETED)
 		return;
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
 	spin_lock(&cifs_tcp_ses_lock);
-	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			if (tcon->tid == le32_to_cpu(shdr->Id.SyncId.TreeId)) {
 				spin_lock(&tcon->tc_lock);
@@ -4264,21 +4268,23 @@ init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign)
 static int
 smb2_get_enc_key(struct TCP_Server_Info *server, __u64 ses_id, int enc, u8 *key)
 {
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses;
 	u8 *ses_enc_key;
 
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
 	spin_lock(&cifs_tcp_ses_lock);
-	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
-		list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+		if (ses->Suid == ses_id) {
-			if (ses->Suid == ses_id) {
+			spin_lock(&ses->ses_lock);
-				spin_lock(&ses->ses_lock);
+			ses_enc_key = enc ? ses->smb3encryptionkey :
-				ses_enc_key = enc ? ses->smb3encryptionkey :
+				ses->smb3decryptionkey;
-					ses->smb3decryptionkey;
+			memcpy(key, ses_enc_key, SMB3_ENC_DEC_KEY_SIZE);
-				memcpy(key, ses_enc_key, SMB3_ENC_DEC_KEY_SIZE);
+			spin_unlock(&ses->ses_lock);
-				spin_unlock(&ses->ses_lock);
+			spin_unlock(&cifs_tcp_ses_lock);
-				spin_unlock(&cifs_tcp_ses_lock);
+			return 0;
-				return 0;
-			}
 		}
 	}
 	spin_unlock(&cifs_tcp_ses_lock);

fs/cifs/smb2transport.c

@@ -77,18 +77,19 @@ static
 int smb2_get_sign_key(__u64 ses_id, struct TCP_Server_Info *server, u8 *key)
 {
 	struct cifs_chan *chan;
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses = NULL;
-	struct TCP_Server_Info *it = NULL;
 	int i;
 	int rc = 0;
 
 	spin_lock(&cifs_tcp_ses_lock);
 
-	list_for_each_entry(it, &cifs_tcp_ses_list, tcp_ses_list) {
+	/* If server is a channel, select the primary channel */
-		list_for_each_entry(ses, &it->smb_ses_list, smb_ses_list) {
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
-			if (ses->Suid == ses_id)
+
-				goto found;
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
-		}
+		if (ses->Suid == ses_id)
+			goto found;
 	}
 	cifs_server_dbg(VFS, "%s: Could not find session 0x%llx\n",
 			__func__, ses_id);
@@ -136,9 +137,13 @@ out:
 static struct cifs_ses *
 smb2_find_smb_ses_unlocked(struct TCP_Server_Info *server, __u64 ses_id)
 {
+	struct TCP_Server_Info *pserver;
 	struct cifs_ses *ses;
 
-	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+	/* If server is a channel, select the primary channel */
+	pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
+
+	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 		if (ses->Suid != ses_id)
 			continue;
 		++ses->ses_count;