NFSv4.2 fix problems with __nfs42_ssc_open

stable inclusion
from stable-v5.10.140
commit 5e49ea099850feadcbf33c74b4f514a3e8049b91
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I63FTT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5e49ea099850feadcbf33c74b4f514a3e8049b91

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

[ Upstream commit fcfc8be1 ]

A destination server while doing a COPY shouldn't accept using the
passed in filehandle if its not a regular filehandle.

If alloc_file_pseudo() has failed, we need to decrement a reference
on the newly created inode, otherwise it leaks.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Fixes: ec4b0925 ("NFS: inter ssc open")
Signed-off-by: NOlga Kornievskaia <kolga@netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

fs/nfs/nfs4file.c

@@ -338,6 +338,11 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 		goto out;
 	}
 
+	if (!S_ISREG(fattr->mode)) {
+		res = ERR_PTR(-EBADF);
+		goto out;
+	}
+
 	res = ERR_PTR(-ENOMEM);
 	len = strlen(SSC_READ_NAME_BODY) + 16;
 	read_name = kzalloc(len, GFP_NOFS);
@@ -356,6 +361,7 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 				     r_ino->i_fop);
 	if (IS_ERR(filep)) {
 		res = ERR_CAST(filep);
+		iput(r_ino);
 		goto out_free_name;
 	}
 	filep->f_mode |= FMODE_READ;