Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6

Pull CIFS/SMB3 fixes from Steve French:
 "Various CIFS/SMB3 fixes, most for stable"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  CIFS: Fix a possible invalid memory access in smb2_query_symlink()
  fs/cifs: make share unaccessible at root level mountable
  cifs: fix crash due to race in hmac(md5) handling
  cifs: unbreak TCP session reuse
  cifs: Check for existing directory when opening file with O_CREAT
  Add MF-Symlinks support for SMB 2.0

7 files changed, 169 insertions, 16 deletions

diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 3182273a3407..1418daa03d95 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -46,6 +46,9 @@
 #define CIFS_MOUNT_CIFS_BACKUPUID 0x200000 /* backup intent bit for a user */
 #define CIFS_MOUNT_CIFS_BACKUPGID 0x400000 /* backup intent bit for a group */
 #define CIFS_MOUNT_MAP_SFM_CHR	0x800000 /* SFM/MAC mapping for illegal chars */
+#define CIFS_MOUNT_USE_PREFIX_PATH 0x1000000 /* make subpath with unaccessible
+					      * root mountable
+					      */
 
 struct cifs_sb_info {
 	struct rb_root tlink_tree;
@@ -67,5 +70,6 @@ struct cifs_sb_info {
 	struct backing_dev_info bdi;
 	struct delayed_work prune_tlinks;
 	struct rcu_head rcu;
+	char *prepath;
 };
 #endif				/* _CIFS_FS_SB_H */
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 6aeb8d4616a4..8347c90cf483 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -743,24 +743,26 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 
 	memcpy(ses->auth_key.response + baselen, tiblob, tilen);
 
+	mutex_lock(&ses->server->srv_mutex);
+
 	rc = crypto_hmacmd5_alloc(ses->server);
 	if (rc) {
 		cifs_dbg(VFS, "could not crypto alloc hmacmd5 rc %d\n", rc);
-		goto setup_ntlmv2_rsp_ret;
+		goto unlock;
 	}
 
 	/* calculate ntlmv2_hash */
 	rc = calc_ntlmv2_hash(ses, ntlmv2_hash, nls_cp);
 	if (rc) {
 		cifs_dbg(VFS, "could not get v2 hash rc %d\n", rc);
-		goto setup_ntlmv2_rsp_ret;
+		goto unlock;
 	}
 
 	/* calculate first part of the client response (CR1) */
 	rc = CalcNTLMv2_response(ses, ntlmv2_hash);
 	if (rc) {
 		cifs_dbg(VFS, "Could not calculate CR1 rc: %d\n", rc);
-		goto setup_ntlmv2_rsp_ret;
+		goto unlock;
 	}
 
 	/* now calculate the session key for NTLMv2 */
@@ -769,13 +771,13 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 	if (rc) {
 		cifs_dbg(VFS, "%s: Could not set NTLMV2 Hash as a key\n",
 			 __func__);
-		goto setup_ntlmv2_rsp_ret;
+		goto unlock;
 	}
 
 	rc = crypto_shash_init(&ses->server->secmech.sdeschmacmd5->shash);
 	if (rc) {
 		cifs_dbg(VFS, "%s: Could not init hmacmd5\n", __func__);
-		goto setup_ntlmv2_rsp_ret;
+		goto unlock;
 	}
 
 	rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
@@ -783,7 +785,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 		CIFS_HMAC_MD5_HASH_SIZE);
 	if (rc) {
 		cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
-		goto setup_ntlmv2_rsp_ret;
+		goto unlock;
 	}
 
 	rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
@@ -791,6 +793,8 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 	if (rc)
 		cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
 
+unlock:
+	mutex_unlock(&ses->server->srv_mutex);
 setup_ntlmv2_rsp_ret:
 	kfree(tiblob);
 
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 5d841f39c4b7..6bbec5e784cd 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -689,6 +689,14 @@ cifs_do_mount(struct file_system_type *fs_type,
 		goto out_cifs_sb;
 	}
 
+	if (volume_info->prepath) {
+		cifs_sb->prepath = kstrdup(volume_info->prepath, GFP_KERNEL);
+		if (cifs_sb->prepath == NULL) {
+			root = ERR_PTR(-ENOMEM);
+			goto out_cifs_sb;
+		}
+	}
+
 	cifs_setup_cifs_sb(volume_info, cifs_sb);
 
 	rc = cifs_mount(cifs_sb, volume_info);
@@ -727,7 +735,11 @@ cifs_do_mount(struct file_system_type *fs_type,
 		sb->s_flags |= MS_ACTIVE;
 	}
 
-	root = cifs_get_root(volume_info, sb);
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
+		root = dget(sb->s_root);
+	else
+		root = cifs_get_root(volume_info, sb);
+
 	if (IS_ERR(root))
 		goto out_super;
 
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7d2b15c06090..7ae03283bd61 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1228,6 +1228,8 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 	vol->ops = &smb1_operations;
 	vol->vals = &smb1_values;
 
+	vol->echo_interval = SMB_ECHO_INTERVAL_DEFAULT;
+
 	if (!mountdata)
 		goto cifs_parse_mount_err;
 
@@ -2049,7 +2051,7 @@ static int match_server(struct TCP_Server_Info *server, struct smb_vol *vol)
 	if (!match_security(server, vol))
 		return 0;
 
-	if (server->echo_interval != vol->echo_interval)
+	if (server->echo_interval != vol->echo_interval * HZ)
 		return 0;
 
 	return 1;
@@ -3483,6 +3485,44 @@ cifs_get_volume_info(char *mount_data, const char *devname)
 	return volume_info;
 }
 
+static int
+cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
+					unsigned int xid,
+					struct cifs_tcon *tcon,
+					struct cifs_sb_info *cifs_sb,
+					char *full_path)
+{
+	int rc;
+	char *s;
+	char sep, tmp;
+
+	sep = CIFS_DIR_SEP(cifs_sb);
+	s = full_path;
+
+	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
+	while (rc == 0) {
+		/* skip separators */
+		while (*s == sep)
+			s++;
+		if (!*s)
+			break;
+		/* next separator */
+		while (*s && *s != sep)
+			s++;
+
+		/*
+		 * temporarily null-terminate the path at the end of
+		 * the current component
+		 */
+		tmp = *s;
+		*s = 0;
+		rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
+						     full_path);
+		*s = tmp;
+	}
+	return rc;
+}
+
 int
 cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 {
@@ -3620,6 +3660,16 @@ remote_path_check:
 			kfree(full_path);
 			goto mount_fail_check;
 		}
+
+		rc = cifs_are_all_path_components_accessible(server,
+							     xid, tcon, cifs_sb,
+							     full_path);
+		if (rc != 0) {
+			cifs_dbg(VFS, "cannot query dirs between root and final path, "
+				 "enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
+			cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+			rc = 0;
+		}
 		kfree(full_path);
 	}
 
@@ -3889,6 +3939,7 @@ cifs_umount(struct cifs_sb_info *cifs_sb)
 
 	bdi_destroy(&cifs_sb->bdi);
 	kfree(cifs_sb->mountdata);
+	kfree(cifs_sb->prepath);
 	call_rcu(&cifs_sb->rcu, delayed_free);
 }
 
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 5efd6f1fb8a5..4e532536cbc6 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -84,6 +84,7 @@ build_path_from_dentry(struct dentry *direntry)
 	struct dentry *temp;
 	int namelen;
 	int dfsplen;
+	int pplen = 0;
 	char *full_path;
 	char dirsep;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
@@ -95,8 +96,12 @@ build_path_from_dentry(struct dentry *direntry)
 		dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);
 	else
 		dfsplen = 0;
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
+		pplen = cifs_sb->prepath ? strlen(cifs_sb->prepath) + 1 : 0;
+
 cifs_bp_rename_retry:
-	namelen = dfsplen;
+	namelen = dfsplen + pplen;
 	seq = read_seqbegin(&rename_lock);
 	rcu_read_lock();
 	for (temp = direntry; !IS_ROOT(temp);) {
@@ -137,7 +142,7 @@ cifs_bp_rename_retry:
 		}
 	}
 	rcu_read_unlock();
-	if (namelen != dfsplen || read_seqretry(&rename_lock, seq)) {
+	if (namelen != dfsplen + pplen || read_seqretry(&rename_lock, seq)) {
 		cifs_dbg(FYI, "did not end path lookup where expected. namelen=%ddfsplen=%d\n",
 			 namelen, dfsplen);
 		/* presumably this is only possible if racing with a rename
@@ -153,6 +158,17 @@ cifs_bp_rename_retry:
 	   those safely to '/' if any are found in the middle of the prepath */
 	/* BB test paths to Windows with '/' in the midst of prepath */
 
+	if (pplen) {
+		int i;
+
+		cifs_dbg(FYI, "using cifs_sb prepath <%s>\n", cifs_sb->prepath);
+		memcpy(full_path+dfsplen+1, cifs_sb->prepath, pplen-1);
+		full_path[dfsplen] = '\\';
+		for (i = 0; i < pplen-1; i++)
+			if (full_path[dfsplen+1+i] == '/')
+				full_path[dfsplen+1+i] = CIFS_DIR_SEP(cifs_sb);
+	}
+
 	if (dfsplen) {
 		strncpy(full_path, tcon->treeName, dfsplen);
 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
@@ -229,6 +245,13 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 				goto cifs_create_get_file_info;
 			}
 
+			if (S_ISDIR(newinode->i_mode)) {
+				CIFSSMBClose(xid, tcon, fid->netfid);
+				iput(newinode);
+				rc = -EISDIR;
+				goto out;
+			}
+
 			if (!S_ISREG(newinode->i_mode)) {
 				/*
 				 * The server may allow us to open things like
@@ -399,10 +422,14 @@ cifs_create_set_dentry:
 	if (rc != 0) {
 		cifs_dbg(FYI, "Create worked, get_inode_info failed rc = %d\n",
 			 rc);
-		if (server->ops->close)
-			server->ops->close(xid, tcon, fid);
-		goto out;
+		goto out_err;
 	}
+
+	if (S_ISDIR(newinode->i_mode)) {
+		rc = -EISDIR;
+		goto out_err;
+	}
+
 	d_drop(direntry);
 	d_add(direntry, newinode);
 
@@ -410,6 +437,13 @@ out:
 	kfree(buf);
 	kfree(full_path);
 	return rc;
+
+out_err:
+	if (server->ops->close)
+		server->ops->close(xid, tcon, fid);
+	if (newinode)
+		iput(newinode);
+	goto out;
 }
 
 int
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 514dadb0575d..b87efd0c92d6 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1002,10 +1002,26 @@ struct inode *cifs_root_iget(struct super_block *sb)
 	struct inode *inode = NULL;
 	long rc;
 	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+	char *path = NULL;
+	int len;
+
+	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
+	    && cifs_sb->prepath) {
+		len = strlen(cifs_sb->prepath);
+		path = kzalloc(len + 2 /* leading sep + null */, GFP_KERNEL);
+		if (path == NULL)
+			return ERR_PTR(-ENOMEM);
+		path[0] = '/';
+		memcpy(path+1, cifs_sb->prepath, len);
+	} else {
+		path = kstrdup("", GFP_KERNEL);
+		if (path == NULL)
+			return ERR_PTR(-ENOMEM);
+	}
 
 	xid = get_xid();
 	if (tcon->unix_ext) {
-		rc = cifs_get_inode_info_unix(&inode, "", sb, xid);
+		rc = cifs_get_inode_info_unix(&inode, path, sb, xid);
 		/* some servers mistakenly claim POSIX support */
 		if (rc != -EOPNOTSUPP)
 			goto iget_no_retry;
@@ -1013,7 +1029,8 @@ struct inode *cifs_root_iget(struct super_block *sb)
 		tcon->unix_ext = false;
 	}
 
-	rc = cifs_get_inode_info(&inode, "", NULL, sb, xid, NULL);
+	convert_delimiter(path, CIFS_DIR_SEP(cifs_sb));
+	rc = cifs_get_inode_info(&inode, path, NULL, sb, xid, NULL);
 
 iget_no_retry:
 	if (!inode) {
@@ -1042,6 +1059,7 @@ iget_no_retry:
 	}
 
 out:
+	kfree(path);
 	/* can not call macro free_xid here since in a void func
 	 * TODO: This is no longer true
 	 */
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 3525ed756173..d203c0329626 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1044,6 +1044,9 @@ smb2_new_lease_key(struct cifs_fid *fid)
 	get_random_bytes(fid->lease_key, SMB2_LEASE_KEY_SIZE);
 }
 
+#define SMB2_SYMLINK_STRUCT_SIZE \
+	(sizeof(struct smb2_err_rsp) - 1 + sizeof(struct smb2_symlink_err_rsp))
+
 static int
 smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 		   const char *full_path, char **target_path,
@@ -1056,7 +1059,10 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cifs_fid fid;
 	struct smb2_err_rsp *err_buf = NULL;
 	struct smb2_symlink_err_rsp *symlink;
-	unsigned int sub_len, sub_offset;
+	unsigned int sub_len;
+	unsigned int sub_offset;
+	unsigned int print_len;
+	unsigned int print_offset;
 
 	cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);
 
@@ -1077,11 +1083,33 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 		kfree(utf16_path);
 		return -ENOENT;
 	}
+
+	if (le32_to_cpu(err_buf->ByteCount) < sizeof(struct smb2_symlink_err_rsp) ||
+	    get_rfc1002_length(err_buf) + 4 < SMB2_SYMLINK_STRUCT_SIZE) {
+		kfree(utf16_path);
+		return -ENOENT;
+	}
+
 	/* open must fail on symlink - reset rc */
 	rc = 0;
 	symlink = (struct smb2_symlink_err_rsp *)err_buf->ErrorData;
 	sub_len = le16_to_cpu(symlink->SubstituteNameLength);
 	sub_offset = le16_to_cpu(symlink->SubstituteNameOffset);
+	print_len = le16_to_cpu(symlink->PrintNameLength);
+	print_offset = le16_to_cpu(symlink->PrintNameOffset);
+
+	if (get_rfc1002_length(err_buf) + 4 <
+			SMB2_SYMLINK_STRUCT_SIZE + sub_offset + sub_len) {
+		kfree(utf16_path);
+		return -ENOENT;
+	}
+
+	if (get_rfc1002_length(err_buf) + 4 <
+			SMB2_SYMLINK_STRUCT_SIZE + print_offset + print_len) {
+		kfree(utf16_path);
+		return -ENOENT;
+	}
+
 	*target_path = cifs_strndup_from_utf16(
 				(char *)symlink->PathBuffer + sub_offset,
 				sub_len, true, cifs_sb->local_nls);
@@ -1515,6 +1543,8 @@ struct smb_version_operations smb20_operations = {
 	.rename = smb2_rename_path,
 	.create_hardlink = smb2_create_hardlink,
 	.query_symlink = smb2_query_symlink,
+	.query_mf_symlink = smb3_query_mf_symlink,
+	.create_mf_symlink = smb3_create_mf_symlink,
 	.open = smb2_open_file,
 	.set_fid = smb2_set_fid,
 	.close = smb2_close_file,