From: Pali Rohár <pali@kernel.org>
Date: Sat, 19 Oct 2024 11:34:18 +0000 (+0200)
Subject: cifs: Check if server supports reparse points before using them
X-Git-Tag: v6.15-rc1~87^2~8
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c06be908ca190e2d8feae1cf452d78598cd0b94;p=thirdparty%2Fkernel%2Fstable.git

cifs: Check if server supports reparse points before using them

Do not attempt to query or create reparse point when server fs does not
support it. This will prevent creating unusable empty object on the server.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index 4fc9485c5d91a..364ab7573b360 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -2709,6 +2709,9 @@ int cifs_query_reparse_point(const unsigned int xid,
 	if (cap_unix(tcon->ses))
 		return -EOPNOTSUPP;
 
+	if (!(le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS))
+		return -EOPNOTSUPP;
+
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
 		.cifs_sb = cifs_sb,
diff --git a/fs/smb/client/link.c b/fs/smb/client/link.c
index 6e6c09cc5ce7a..a882536682860 100644
--- a/fs/smb/client/link.c
+++ b/fs/smb/client/link.c
@@ -643,7 +643,8 @@ cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
 	case CIFS_SYMLINK_TYPE_NATIVE:
 	case CIFS_SYMLINK_TYPE_NFS:
 	case CIFS_SYMLINK_TYPE_WSL:
-		if (server->ops->create_reparse_symlink) {
+		if (server->ops->create_reparse_symlink &&
+		    (le32_to_cpu(pTcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS)) {
 			rc = server->ops->create_reparse_symlink(xid, inode,
 								 direntry,
 								 pTcon,
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 826b57a5a2a8d..e9fd3e204a6f4 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -1273,6 +1273,14 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
 	int rc;
 	int i;
 
+	/*
+	 * If server filesystem does not support reparse points then do not
+	 * attempt to create reparse point. This will prevent creating unusable
+	 * empty object on the server.
+	 */
+	if (!(le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS))
+		return ERR_PTR(-EOPNOTSUPP);
+
 	oparms = CIFS_OPARMS(cifs_sb, tcon, full_path,
 			     SYNCHRONIZE | DELETE |
 			     FILE_READ_ATTRIBUTES |
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 6958825431af2..a700e59219614 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -5229,7 +5229,7 @@ static int smb2_make_node(unsigned int xid, struct inode *inode,
 			  const char *full_path, umode_t mode, dev_t dev)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
-	int rc;
+	int rc = -EOPNOTSUPP;
 
 	/*
 	 * Check if mounted with mount parm 'sfu' mount parm.
@@ -5240,7 +5240,7 @@ static int smb2_make_node(unsigned int xid, struct inode *inode,
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
 		rc = cifs_sfu_make_node(xid, inode, dentry, tcon,
 					full_path, mode, dev);
-	} else {
+	} else if (le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS) {
 		rc = smb2_mknod_reparse(xid, inode, dentry, tcon,
 					full_path, mode, dev);
 	}