smb311: failure to open files of length 1040 when mounting with SMB3.1.1 POSIX extensions

If a file size has bits 0x410 = ATTR_DIRECTORY | ATTR_REPARSE set
then during queryinfo (stat) the file is regarded as a directory
and subsequent opens can fail. A simple test example is trying
to open any file 1040 bytes long when mounting with "posix"
(SMB3.1.1 POSIX/Linux Extensions).

The cause of this bug is that Attributes field in smb2_file_all_info
struct occupies the same place that EndOfFile field in
smb311_posix_qinfo, and sometimes the latter struct is incorrectly
processed as if it was the first one.

Reported-by: Oleh Nykyforchyn <oleh.nyk@gmail.com>
Tested-by: Oleh Nykyforchyn <oleh.nyk@gmail.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: smfrench

fs/smb/client/cifsglob.h

@@ -253,6 +253,7 @@ struct cifs_cred {
 struct cifs_open_info_data {
 	bool adjust_tz;
 	bool reparse_point;
+	bool contains_posix_file_info;
 	struct {
 		/* ioctl response buffer */
 		struct {

fs/smb/client/reparse.h

@@ -99,14 +99,30 @@ static inline bool reparse_inode_match(struct inode *inode,
 
 static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
 {
-	struct smb2_file_all_info *fi = &data->fi;
-	u32 attrs = le32_to_cpu(fi->Attributes);
+	u32 attrs;
 	bool ret;
 
-	ret = data->reparse_point || (attrs & ATTR_REPARSE);
-	if (ret)
-		attrs |= ATTR_REPARSE;
-	fi->Attributes = cpu_to_le32(attrs);
+	if (data->contains_posix_file_info) {
+		struct smb311_posix_qinfo *fi = &data->posix_fi;
+
+		attrs = le32_to_cpu(fi->DosAttributes);
+		if (data->reparse_point) {
+			attrs |= ATTR_REPARSE;
+			fi->DosAttributes = cpu_to_le32(attrs);
+		}
+
+	} else {
+		struct smb2_file_all_info *fi = &data->fi;
+
+		attrs = le32_to_cpu(fi->Attributes);
+		if (data->reparse_point) {
+			attrs |= ATTR_REPARSE;
+			fi->Attributes = cpu_to_le32(attrs);
+		}
+	}
+
+	ret = attrs & ATTR_REPARSE;
+
 	return ret;
 }
 

fs/smb/client/smb2inode.c

@@ -650,6 +650,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		switch (cmds[i]) {
 		case SMB2_OP_QUERY_INFO:
 			idata = in_iov[i].iov_base;
+			idata->contains_posix_file_info = false;
 			if (rc == 0 && cfile && cfile->symlink_target) {
 				idata->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
 				if (!idata->symlink_target)
@@ -673,6 +674,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 			break;
 		case SMB2_OP_POSIX_QUERY_INFO:
 			idata = in_iov[i].iov_base;
+			idata->contains_posix_file_info = true;
 			if (rc == 0 && cfile && cfile->symlink_target) {
 				idata->symlink_target = kstrdup(cfile->symlink_target, GFP_KERNEL);
 				if (!idata->symlink_target)
@@ -770,6 +772,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 				idata = in_iov[i].iov_base;
 				idata->reparse.io.iov = *iov;
 				idata->reparse.io.buftype = resp_buftype[i + 1];
+				idata->contains_posix_file_info = false; /* BB VERIFY */
 				rbuf = reparse_buf_ptr(iov);
 				if (IS_ERR(rbuf)) {
 					rc = PTR_ERR(rbuf);
@@ -791,6 +794,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		case SMB2_OP_QUERY_WSL_EA:
 			if (!rc) {
 				idata = in_iov[i].iov_base;
+				idata->contains_posix_file_info = false;
 				qi_rsp = rsp_iov[i + 1].iov_base;
 				data[0] = (u8 *)qi_rsp + le16_to_cpu(qi_rsp->OutputBufferOffset);
 				size[0] = le32_to_cpu(qi_rsp->OutputBufferLength);

fs/smb/client/smb2ops.c

@@ -1001,6 +1001,7 @@ static int smb2_query_file_info(const unsigned int xid, struct cifs_tcon *tcon,
 		if (!data->symlink_target)
 			return -ENOMEM;
 	}
+	data->contains_posix_file_info = false;
 	return SMB2_query_info(xid, tcon, fid->persistent_fid, fid->volatile_fid, &data->fi);
 }
 
@@ -5146,7 +5147,7 @@ int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
 			     FILE_CREATE, CREATE_NOT_DIR |
 			     CREATE_OPTION_SPECIAL, ACL_NO_MODE);
 	oparms.fid = &fid;
-
+	idata.contains_posix_file_info = false;
 	rc = server->ops->open(xid, &oparms, &oplock, &idata);
 	if (rc)
 		goto out;