1 files changed, 532 insertions, 0 deletions

diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c
new file mode 100644
index 000000000000..a0ffbda90733
--- /dev/null
+++ b/fs/smb/client/reparse.c
@@ -0,0 +1,532 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024 Paulo Alcantara <pc@manguebit.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include "cifsglob.h"
+#include "smb2proto.h"
+#include "cifsproto.h"
+#include "cifs_unicode.h"
+#include "cifs_debug.h"
+#include "fs_context.h"
+#include "reparse.h"
+
+int smb2_create_reparse_symlink(const unsigned int xid, struct inode *inode,
+				struct dentry *dentry, struct cifs_tcon *tcon,
+				const char *full_path, const char *symname)
+{
+	struct reparse_symlink_data_buffer *buf = NULL;
+	struct cifs_open_info_data data;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct inode *new;
+	struct kvec iov;
+	__le16 *path;
+	char *sym, sep = CIFS_DIR_SEP(cifs_sb);
+	u16 len, plen;
+	int rc = 0;
+
+	sym = kstrdup(symname, GFP_KERNEL);
+	if (!sym)
+		return -ENOMEM;
+
+	data = (struct cifs_open_info_data) {
+		.reparse_point = true,
+		.reparse = { .tag = IO_REPARSE_TAG_SYMLINK, },
+		.symlink_target = sym,
+	};
+
+	convert_delimiter(sym, sep);
+	path = cifs_convert_path_to_utf16(sym, cifs_sb);
+	if (!path) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	plen = 2 * UniStrnlen((wchar_t *)path, PATH_MAX);
+	len = sizeof(*buf) + plen * 2;
+	buf = kzalloc(len, GFP_KERNEL);
+	if (!buf) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	buf->ReparseTag = cpu_to_le32(IO_REPARSE_TAG_SYMLINK);
+	buf->ReparseDataLength = cpu_to_le16(len - sizeof(struct reparse_data_buffer));
+	buf->SubstituteNameOffset = cpu_to_le16(plen);
+	buf->SubstituteNameLength = cpu_to_le16(plen);
+	memcpy(&buf->PathBuffer[plen], path, plen);
+	buf->PrintNameOffset = 0;
+	buf->PrintNameLength = cpu_to_le16(plen);
+	memcpy(buf->PathBuffer, path, plen);
+	buf->Flags = cpu_to_le32(*symname != '/' ? SYMLINK_FLAG_RELATIVE : 0);
+	if (*sym != sep)
+		buf->Flags = cpu_to_le32(SYMLINK_FLAG_RELATIVE);
+
+	convert_delimiter(sym, '/');
+	iov.iov_base = buf;
+	iov.iov_len = len;
+	new = smb2_get_reparse_inode(&data, inode->i_sb, xid,
+				     tcon, full_path, &iov, NULL);
+	if (!IS_ERR(new))
+		d_instantiate(dentry, new);
+	else
+		rc = PTR_ERR(new);
+out:
+	kfree(path);
+	cifs_free_open_info(&data);
+	kfree(buf);
+	return rc;
+}
+
+static int nfs_set_reparse_buf(struct reparse_posix_data *buf,
+			       mode_t mode, dev_t dev,
+			       struct kvec *iov)
+{
+	u64 type;
+	u16 len, dlen;
+
+	len = sizeof(*buf);
+
+	switch ((type = reparse_mode_nfs_type(mode))) {
+	case NFS_SPECFILE_BLK:
+	case NFS_SPECFILE_CHR:
+		dlen = sizeof(__le64);
+		break;
+	case NFS_SPECFILE_FIFO:
+	case NFS_SPECFILE_SOCK:
+		dlen = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	buf->ReparseTag = cpu_to_le32(IO_REPARSE_TAG_NFS);
+	buf->Reserved = 0;
+	buf->InodeType = cpu_to_le64(type);
+	buf->ReparseDataLength = cpu_to_le16(len + dlen -
+					     sizeof(struct reparse_data_buffer));
+	*(__le64 *)buf->DataBuffer = cpu_to_le64(((u64)MAJOR(dev) << 32) |
+						 MINOR(dev));
+	iov->iov_base = buf;
+	iov->iov_len = len + dlen;
+	return 0;
+}
+
+static int mknod_nfs(unsigned int xid, struct inode *inode,
+		     struct dentry *dentry, struct cifs_tcon *tcon,
+		     const char *full_path, umode_t mode, dev_t dev)
+{
+	struct cifs_open_info_data data;
+	struct reparse_posix_data *p;
+	struct inode *new;
+	struct kvec iov;
+	__u8 buf[sizeof(*p) + sizeof(__le64)];
+	int rc;
+
+	p = (struct reparse_posix_data *)buf;
+	rc = nfs_set_reparse_buf(p, mode, dev, &iov);
+	if (rc)
+		return rc;
+
+	data = (struct cifs_open_info_data) {
+		.reparse_point = true,
+		.reparse = { .tag = IO_REPARSE_TAG_NFS, .posix = p, },
+	};
+
+	new = smb2_get_reparse_inode(&data, inode->i_sb, xid,
+				     tcon, full_path, &iov, NULL);
+	if (!IS_ERR(new))
+		d_instantiate(dentry, new);
+	else
+		rc = PTR_ERR(new);
+	cifs_free_open_info(&data);
+	return rc;
+}
+
+static int wsl_set_reparse_buf(struct reparse_data_buffer *buf,
+			       mode_t mode, struct kvec *iov)
+{
+	u32 tag;
+
+	switch ((tag = reparse_mode_wsl_tag(mode))) {
+	case IO_REPARSE_TAG_LX_BLK:
+	case IO_REPARSE_TAG_LX_CHR:
+	case IO_REPARSE_TAG_LX_FIFO:
+	case IO_REPARSE_TAG_AF_UNIX:
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	buf->ReparseTag = cpu_to_le32(tag);
+	buf->Reserved = 0;
+	buf->ReparseDataLength = 0;
+	iov->iov_base = buf;
+	iov->iov_len = sizeof(*buf);
+	return 0;
+}
+
+static struct smb2_create_ea_ctx *ea_create_context(u32 dlen, size_t *cc_len)
+{
+	struct smb2_create_ea_ctx *cc;
+
+	*cc_len = round_up(sizeof(*cc) + dlen, 8);
+	cc = kzalloc(*cc_len, GFP_KERNEL);
+	if (!cc)
+		return ERR_PTR(-ENOMEM);
+
+	cc->ctx.NameOffset = cpu_to_le16(offsetof(struct smb2_create_ea_ctx,
+						  name));
+	cc->ctx.NameLength = cpu_to_le16(4);
+	memcpy(cc->name, SMB2_CREATE_EA_BUFFER, strlen(SMB2_CREATE_EA_BUFFER));
+	cc->ctx.DataOffset = cpu_to_le16(offsetof(struct smb2_create_ea_ctx, ea));
+	cc->ctx.DataLength = cpu_to_le32(dlen);
+	return cc;
+}
+
+struct wsl_xattr {
+	const char	*name;
+	__le64		value;
+	u16		size;
+	u32		next;
+};
+
+static int wsl_set_xattrs(struct inode *inode, umode_t _mode,
+			  dev_t _dev, struct kvec *iov)
+{
+	struct smb2_file_full_ea_info *ea;
+	struct smb2_create_ea_ctx *cc;
+	struct smb3_fs_context *ctx = CIFS_SB(inode->i_sb)->ctx;
+	__le64 uid = cpu_to_le64(from_kuid(current_user_ns(), ctx->linux_uid));
+	__le64 gid = cpu_to_le64(from_kgid(current_user_ns(), ctx->linux_gid));
+	__le64 dev = cpu_to_le64(((u64)MINOR(_dev) << 32) | MAJOR(_dev));
+	__le64 mode = cpu_to_le64(_mode);
+	struct wsl_xattr xattrs[] = {
+		{ .name = SMB2_WSL_XATTR_UID,  .value = uid,  .size = SMB2_WSL_XATTR_UID_SIZE, },
+		{ .name = SMB2_WSL_XATTR_GID,  .value = gid,  .size = SMB2_WSL_XATTR_GID_SIZE, },
+		{ .name = SMB2_WSL_XATTR_MODE, .value = mode, .size = SMB2_WSL_XATTR_MODE_SIZE, },
+		{ .name = SMB2_WSL_XATTR_DEV,  .value = dev, .size = SMB2_WSL_XATTR_DEV_SIZE, },
+	};
+	size_t cc_len;
+	u32 dlen = 0, next = 0;
+	int i, num_xattrs;
+	u8 name_size = SMB2_WSL_XATTR_NAME_LEN + 1;
+
+	memset(iov, 0, sizeof(*iov));
+
+	/* Exclude $LXDEV xattr for sockets and fifos */
+	if (S_ISSOCK(_mode) || S_ISFIFO(_mode))
+		num_xattrs = ARRAY_SIZE(xattrs) - 1;
+	else
+		num_xattrs = ARRAY_SIZE(xattrs);
+
+	for (i = 0; i < num_xattrs; i++) {
+		xattrs[i].next = ALIGN(sizeof(*ea) + name_size +
+				       xattrs[i].size, 4);
+		dlen += xattrs[i].next;
+	}
+
+	cc = ea_create_context(dlen, &cc_len);
+	if (IS_ERR(cc))
+		return PTR_ERR(cc);
+
+	ea = &cc->ea;
+	for (i = 0; i < num_xattrs; i++) {
+		ea = (void *)((u8 *)ea + next);
+		next = xattrs[i].next;
+		ea->next_entry_offset = cpu_to_le32(next);
+
+		ea->ea_name_length = name_size - 1;
+		ea->ea_value_length = cpu_to_le16(xattrs[i].size);
+		memcpy(ea->ea_data, xattrs[i].name, name_size);
+		memcpy(&ea->ea_data[name_size],
+		       &xattrs[i].value, xattrs[i].size);
+	}
+	ea->next_entry_offset = 0;
+
+	iov->iov_base = cc;
+	iov->iov_len = cc_len;
+	return 0;
+}
+
+static int mknod_wsl(unsigned int xid, struct inode *inode,
+		     struct dentry *dentry, struct cifs_tcon *tcon,
+		     const char *full_path, umode_t mode, dev_t dev)
+{
+	struct cifs_open_info_data data;
+	struct reparse_data_buffer buf;
+	struct smb2_create_ea_ctx *cc;
+	struct inode *new;
+	unsigned int len;
+	struct kvec reparse_iov, xattr_iov;
+	int rc;
+
+	rc = wsl_set_reparse_buf(&buf, mode, &reparse_iov);
+	if (rc)
+		return rc;
+
+	rc = wsl_set_xattrs(inode, mode, dev, &xattr_iov);
+	if (rc)
+		return rc;
+
+	data = (struct cifs_open_info_data) {
+		.reparse_point = true,
+		.reparse = { .tag = le32_to_cpu(buf.ReparseTag), .buf = &buf, },
+	};
+
+	cc = xattr_iov.iov_base;
+	len = le32_to_cpu(cc->ctx.DataLength);
+	memcpy(data.wsl.eas, &cc->ea, len);
+	data.wsl.eas_len = len;
+
+	new = smb2_get_reparse_inode(&data, inode->i_sb,
+				     xid, tcon, full_path,
+				     &reparse_iov, &xattr_iov);
+	if (!IS_ERR(new))
+		d_instantiate(dentry, new);
+	else
+		rc = PTR_ERR(new);
+	cifs_free_open_info(&data);
+	kfree(xattr_iov.iov_base);
+	return rc;
+}
+
+int smb2_mknod_reparse(unsigned int xid, struct inode *inode,
+		       struct dentry *dentry, struct cifs_tcon *tcon,
+		       const char *full_path, umode_t mode, dev_t dev)
+{
+	struct smb3_fs_context *ctx = CIFS_SB(inode->i_sb)->ctx;
+	int rc = -EOPNOTSUPP;
+
+	switch (ctx->reparse_type) {
+	case CIFS_REPARSE_TYPE_NFS:
+		rc = mknod_nfs(xid, inode, dentry, tcon, full_path, mode, dev);
+		break;
+	case CIFS_REPARSE_TYPE_WSL:
+		rc = mknod_wsl(xid, inode, dentry, tcon, full_path, mode, dev);
+		break;
+	}
+	return rc;
+}
+
+/* See MS-FSCC 2.1.2.6 for the 'NFS' style reparse tags */
+static int parse_reparse_posix(struct reparse_posix_data *buf,
+			       struct cifs_sb_info *cifs_sb,
+			       struct cifs_open_info_data *data)
+{
+	unsigned int len;
+	u64 type;
+
+	switch ((type = le64_to_cpu(buf->InodeType))) {
+	case NFS_SPECFILE_LNK:
+		len = le16_to_cpu(buf->ReparseDataLength);
+		data->symlink_target = cifs_strndup_from_utf16(buf->DataBuffer,
+							       len, true,
+							       cifs_sb->local_nls);
+		if (!data->symlink_target)
+			return -ENOMEM;
+		convert_delimiter(data->symlink_target, '/');
+		cifs_dbg(FYI, "%s: target path: %s\n",
+			 __func__, data->symlink_target);
+		break;
+	case NFS_SPECFILE_CHR:
+	case NFS_SPECFILE_BLK:
+	case NFS_SPECFILE_FIFO:
+	case NFS_SPECFILE_SOCK:
+		break;
+	default:
+		cifs_dbg(VFS, "%s: unhandled inode type: 0x%llx\n",
+			 __func__, type);
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int parse_reparse_symlink(struct reparse_symlink_data_buffer *sym,
+				 u32 plen, bool unicode,
+				 struct cifs_sb_info *cifs_sb,
+				 struct cifs_open_info_data *data)
+{
+	unsigned int len;
+	unsigned int offs;
+
+	/* We handle Symbolic Link reparse tag here. See: MS-FSCC 2.1.2.4 */
+
+	offs = le16_to_cpu(sym->SubstituteNameOffset);
+	len = le16_to_cpu(sym->SubstituteNameLength);
+	if (offs + 20 > plen || offs + len + 20 > plen) {
+		cifs_dbg(VFS, "srv returned malformed symlink buffer\n");
+		return -EIO;
+	}
+
+	data->symlink_target = cifs_strndup_from_utf16(sym->PathBuffer + offs,
+						       len, unicode,
+						       cifs_sb->local_nls);
+	if (!data->symlink_target)
+		return -ENOMEM;
+
+	convert_delimiter(data->symlink_target, '/');
+	cifs_dbg(FYI, "%s: target path: %s\n", __func__, data->symlink_target);
+
+	return 0;
+}
+
+int parse_reparse_point(struct reparse_data_buffer *buf,
+			u32 plen, struct cifs_sb_info *cifs_sb,
+			bool unicode, struct cifs_open_info_data *data)
+{
+	data->reparse.buf = buf;
+
+	/* See MS-FSCC 2.1.2 */
+	switch (le32_to_cpu(buf->ReparseTag)) {
+	case IO_REPARSE_TAG_NFS:
+		return parse_reparse_posix((struct reparse_posix_data *)buf,
+					   cifs_sb, data);
+	case IO_REPARSE_TAG_SYMLINK:
+		return parse_reparse_symlink(
+			(struct reparse_symlink_data_buffer *)buf,
+			plen, unicode, cifs_sb, data);
+	case IO_REPARSE_TAG_LX_SYMLINK:
+	case IO_REPARSE_TAG_AF_UNIX:
+	case IO_REPARSE_TAG_LX_FIFO:
+	case IO_REPARSE_TAG_LX_CHR:
+	case IO_REPARSE_TAG_LX_BLK:
+		return 0;
+	default:
+		cifs_dbg(VFS, "%s: unhandled reparse tag: 0x%08x\n",
+			 __func__, le32_to_cpu(buf->ReparseTag));
+		return -EOPNOTSUPP;
+	}
+}
+
+int smb2_parse_reparse_point(struct cifs_sb_info *cifs_sb,
+			     struct kvec *rsp_iov,
+			     struct cifs_open_info_data *data)
+{
+	struct reparse_data_buffer *buf;
+	struct smb2_ioctl_rsp *io = rsp_iov->iov_base;
+	u32 plen = le32_to_cpu(io->OutputCount);
+
+	buf = (struct reparse_data_buffer *)((u8 *)io +
+					     le32_to_cpu(io->OutputOffset));
+	return parse_reparse_point(buf, plen, cifs_sb, true, data);
+}
+
+static void wsl_to_fattr(struct cifs_open_info_data *data,
+			 struct cifs_sb_info *cifs_sb,
+			 u32 tag, struct cifs_fattr *fattr)
+{
+	struct smb2_file_full_ea_info *ea;
+	u32 next = 0;
+
+	switch (tag) {
+	case IO_REPARSE_TAG_LX_SYMLINK:
+		fattr->cf_mode |= S_IFLNK;
+		break;
+	case IO_REPARSE_TAG_LX_FIFO:
+		fattr->cf_mode |= S_IFIFO;
+		break;
+	case IO_REPARSE_TAG_AF_UNIX:
+		fattr->cf_mode |= S_IFSOCK;
+		break;
+	case IO_REPARSE_TAG_LX_CHR:
+		fattr->cf_mode |= S_IFCHR;
+		break;
+	case IO_REPARSE_TAG_LX_BLK:
+		fattr->cf_mode |= S_IFBLK;
+		break;
+	}
+
+	if (!data->wsl.eas_len)
+		goto out;
+
+	ea = (struct smb2_file_full_ea_info *)data->wsl.eas;
+	do {
+		const char *name;
+		void *v;
+		u8 nlen;
+
+		ea = (void *)((u8 *)ea + next);
+		next = le32_to_cpu(ea->next_entry_offset);
+		if (!le16_to_cpu(ea->ea_value_length))
+			continue;
+
+		name = ea->ea_data;
+		nlen = ea->ea_name_length;
+		v = (void *)((u8 *)ea->ea_data + ea->ea_name_length + 1);
+
+		if (!strncmp(name, SMB2_WSL_XATTR_UID, nlen))
+			fattr->cf_uid = wsl_make_kuid(cifs_sb, v);
+		else if (!strncmp(name, SMB2_WSL_XATTR_GID, nlen))
+			fattr->cf_gid = wsl_make_kgid(cifs_sb, v);
+		else if (!strncmp(name, SMB2_WSL_XATTR_MODE, nlen))
+			fattr->cf_mode = (umode_t)le32_to_cpu(*(__le32 *)v);
+		else if (!strncmp(name, SMB2_WSL_XATTR_DEV, nlen))
+			fattr->cf_rdev = wsl_mkdev(v);
+	} while (next);
+out:
+	fattr->cf_dtype = S_DT(fattr->cf_mode);
+}
+
+bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
+				 struct cifs_fattr *fattr,
+				 struct cifs_open_info_data *data)
+{
+	struct reparse_posix_data *buf = data->reparse.posix;
+	u32 tag = data->reparse.tag;
+
+	if (tag == IO_REPARSE_TAG_NFS && buf) {
+		switch (le64_to_cpu(buf->InodeType)) {
+		case NFS_SPECFILE_CHR:
+			fattr->cf_mode |= S_IFCHR;
+			fattr->cf_rdev = reparse_nfs_mkdev(buf);
+			break;
+		case NFS_SPECFILE_BLK:
+			fattr->cf_mode |= S_IFBLK;
+			fattr->cf_rdev = reparse_nfs_mkdev(buf);
+			break;
+		case NFS_SPECFILE_FIFO:
+			fattr->cf_mode |= S_IFIFO;
+			break;
+		case NFS_SPECFILE_SOCK:
+			fattr->cf_mode |= S_IFSOCK;
+			break;
+		case NFS_SPECFILE_LNK:
+			fattr->cf_mode |= S_IFLNK;
+			break;
+		default:
+			WARN_ON_ONCE(1);
+			return false;
+		}
+		goto out;
+	}
+
+	switch (tag) {
+	case IO_REPARSE_TAG_DFS:
+	case IO_REPARSE_TAG_DFSR:
+	case IO_REPARSE_TAG_MOUNT_POINT:
+		/* See cifs_create_junction_fattr() */
+		fattr->cf_mode = S_IFDIR | 0711;
+		break;
+	case IO_REPARSE_TAG_LX_SYMLINK:
+	case IO_REPARSE_TAG_LX_FIFO:
+	case IO_REPARSE_TAG_AF_UNIX:
+	case IO_REPARSE_TAG_LX_CHR:
+	case IO_REPARSE_TAG_LX_BLK:
+		wsl_to_fattr(data, cifs_sb, tag, fattr);
+		break;
+	case 0: /* SMB1 symlink */
+	case IO_REPARSE_TAG_SYMLINK:
+	case IO_REPARSE_TAG_NFS:
+		fattr->cf_mode |= S_IFLNK;
+		break;
+	default:
+		return false;
+	}
+out:
+	fattr->cf_dtype = S_DT(fattr->cf_mode);
+	return true;
+}