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CIFS: Implement follow_link for SMB2

that allows to access files through symlink created on a server.

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
master
Pavel Shilovsky 9 years ago committed by Steve French
parent
commit
b42bf88828
  1. 3
      fs/cifs/cifsglob.h
  2. 4
      fs/cifs/inode.c
  3. 24
      fs/cifs/link.c
  4. 3
      fs/cifs/readdir.c
  5. 2
      fs/cifs/smb2file.c
  6. 9
      fs/cifs/smb2inode.c
  7. 4
      fs/cifs/smb2misc.c
  8. 60
      fs/cifs/smb2ops.c
  9. 6
      fs/cifs/smb2pdu.c
  10. 14
      fs/cifs/smb2pdu.h
  11. 3
      fs/cifs/smb2proto.h

3
fs/cifs/cifsglob.h

@ -308,6 +308,9 @@ struct smb_version_operations {
int (*create_hardlink)(const unsigned int, struct cifs_tcon *,
const char *, const char *,
struct cifs_sb_info *);
/* query symlink target */
int (*query_symlink)(const unsigned int, struct cifs_tcon *,
const char *, char **, struct cifs_sb_info *);
/* open a file for non-posix mounts */
int (*open)(const unsigned int, struct cifs_open_parms *,
__u32 *, FILE_ALL_INFO *);

4
fs/cifs/inode.c

@ -549,6 +549,10 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
* when Unix extensions are disabled - fake it.
*/
fattr->cf_nlink = 2;
} else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
fattr->cf_mode = S_IFLNK;
fattr->cf_dtype = DT_LNK;
fattr->cf_nlink = le32_to_cpu(info->NumberOfLinks);
} else {
fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
fattr->cf_dtype = DT_REG;

24
fs/cifs/link.c

@ -509,6 +509,7 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
struct tcon_link *tlink = NULL;
struct cifs_tcon *tcon;
struct TCP_Server_Info *server;
xid = get_xid();
@ -519,25 +520,7 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
goto out;
}
tcon = tlink_tcon(tlink);
/*
* For now, we just handle symlinks with unix extensions enabled.
* Eventually we should handle NTFS reparse points, and MacOS
* symlink support. For instance...
*
* rc = CIFSSMBQueryReparseLinkInfo(...)
*
* For now, just return -EACCES when the server doesn't support posix
* extensions. Note that we still allow querying symlinks when posix
* extensions are manually disabled. We could disable these as well
* but there doesn't seem to be any harm in allowing the client to
* read them.
*/
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
!cap_unix(tcon->ses)) {
rc = -EACCES;
goto out;
}
server = tcon->ses->server;
full_path = build_path_from_dentry(direntry);
if (!full_path)
@ -559,6 +542,9 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
if ((rc != 0) && cap_unix(tcon->ses))
rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
cifs_sb->local_nls);
else if (rc != 0 && server->ops->query_symlink)
rc = server->ops->query_symlink(xid, tcon, full_path,
&target_path, cifs_sb);
kfree(full_path);
out:

3
fs/cifs/readdir.c

@ -172,6 +172,9 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
if (cifs_dfs_is_possible(cifs_sb) &&
(fattr->cf_cifsattrs & ATTR_REPARSE))
fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
} else if (fattr->cf_cifsattrs & ATTR_REPARSE) {
fattr->cf_mode = S_IFLNK;
fattr->cf_dtype = DT_LNK;
} else {
fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
fattr->cf_dtype = DT_REG;

2
fs/cifs/smb2file.c

@ -86,7 +86,7 @@ smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
if (oparms->tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
memcpy(smb2_oplock + 1, fid->lease_key, SMB2_LEASE_KEY_SIZE);
rc = SMB2_open(xid, oparms, smb2_path, smb2_oplock, smb2_data);
rc = SMB2_open(xid, oparms, smb2_path, smb2_oplock, smb2_data, NULL);
if (rc)
goto out;

9
fs/cifs/smb2inode.c

@ -60,7 +60,7 @@ smb2_open_op_close(const unsigned int xid, struct cifs_tcon *tcon,
oparms.fid = &fid;
oparms.reconnect = false;
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL);
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
if (rc) {
kfree(utf16_path);
return rc;
@ -136,7 +136,8 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
return -ENOMEM;
rc = smb2_open_op_close(xid, tcon, cifs_sb, full_path,
FILE_READ_ATTRIBUTES, FILE_OPEN, 0, smb2_data,
FILE_READ_ATTRIBUTES, FILE_OPEN,
OPEN_REPARSE_POINT, smb2_data,
SMB2_OP_QUERY_INFO);
if (rc)
goto out;
@ -191,8 +192,8 @@ smb2_unlink(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
struct cifs_sb_info *cifs_sb)
{
return smb2_open_op_close(xid, tcon, cifs_sb, name, DELETE, FILE_OPEN,
CREATE_DELETE_ON_CLOSE, NULL,
SMB2_OP_DELETE);
CREATE_DELETE_ON_CLOSE | OPEN_REPARSE_POINT,
NULL, SMB2_OP_DELETE);
}
static int

4
fs/cifs/smb2misc.c

@ -171,6 +171,10 @@ smb2_check_message(char *buf, unsigned int length)
if (4 + len != clc_len) {
cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
clc_len, 4 + len, mid);
/* create failed on symlink */
if (command == SMB2_CREATE_HE &&
hdr->Status == STATUS_STOPPED_ON_SYMLINK)
return 0;
/* Windows 7 server returns 24 bytes more */
if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
return 0;

60
fs/cifs/smb2ops.c

@ -24,6 +24,7 @@
#include "smb2proto.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "smb2status.h"
#include "smb2glob.h"
@ -229,7 +230,7 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
oparms.fid = &fid;
oparms.reconnect = false;
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL);
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
if (rc) {
kfree(utf16_path);
return rc;
@ -463,7 +464,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
oparms.fid = fid;
oparms.reconnect = false;
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL);
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
kfree(utf16_path);
if (rc) {
cifs_dbg(VFS, "open dir failed\n");
@ -550,7 +551,7 @@ smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
oparms.fid = &fid;
oparms.reconnect = false;
rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL);
rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL);
if (rc)
return rc;
buf->f_type = SMB2_MAGIC_NUMBER;
@ -596,6 +597,57 @@ smb2_new_lease_key(struct cifs_fid *fid)
get_random_bytes(fid->lease_key, SMB2_LEASE_KEY_SIZE);
}
static int
smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
const char *full_path, char **target_path,
struct cifs_sb_info *cifs_sb)
{
int rc;
__le16 *utf16_path;
__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
struct cifs_open_parms oparms;
struct cifs_fid fid;
struct smb2_err_rsp *err_buf = NULL;
struct smb2_symlink_err_rsp *symlink;
unsigned int sub_len, sub_offset;
cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);
utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
if (!utf16_path)
return -ENOMEM;
oparms.tcon = tcon;
oparms.desired_access = FILE_READ_ATTRIBUTES;
oparms.disposition = FILE_OPEN;
oparms.create_options = 0;
oparms.fid = &fid;
oparms.reconnect = false;
rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, &err_buf);
if (!rc || !err_buf) {
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);
*target_path = cifs_strndup_from_utf16(
(char *)symlink->PathBuffer + sub_offset,
sub_len, true, cifs_sb->local_nls);
if (!(*target_path)) {
kfree(utf16_path);
return -ENOMEM;
}
convert_delimiter(*target_path, '/');
cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);
kfree(utf16_path);
return rc;
}
struct smb_version_operations smb21_operations = {
.compare_fids = smb2_compare_fids,
.setup_request = smb2_setup_request,
@ -638,6 +690,7 @@ struct smb_version_operations smb21_operations = {
.unlink = smb2_unlink,
.rename = smb2_rename_path,
.create_hardlink = smb2_create_hardlink,
.query_symlink = smb2_query_symlink,
.open = smb2_open_file,
.set_fid = smb2_set_fid,
.close = smb2_close_file,
@ -706,6 +759,7 @@ struct smb_version_operations smb30_operations = {
.unlink = smb2_unlink,
.rename = smb2_rename_path,
.create_hardlink = smb2_create_hardlink,
.query_symlink = smb2_query_symlink,
.open = smb2_open_file,
.set_fid = smb2_set_fid,
.close = smb2_close_file,

6
fs/cifs/smb2pdu.c

@ -977,7 +977,8 @@ add_durable_context(struct kvec *iov, unsigned int *num_iovec,
int
SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
__u8 *oplock, struct smb2_file_all_info *buf)
__u8 *oplock, struct smb2_file_all_info *buf,
struct smb2_err_rsp **err_buf)
{
struct smb2_create_req *req;
struct smb2_create_rsp *rsp;
@ -1082,6 +1083,9 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
if (rc != 0) {
cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
if (err_buf)
*err_buf = kmemdup(rsp, get_rfc1002_length(rsp) + 4,
GFP_KERNEL);
goto creat_exit;
}

14
fs/cifs/smb2pdu.h

@ -150,6 +150,20 @@ struct smb2_err_rsp {
__u8 ErrorData[1]; /* variable length */
} __packed;
struct smb2_symlink_err_rsp {
__le32 SymLinkLength;
__le32 SymLinkErrorTag;
__le32 ReparseTag;
__le16 ReparseDataLength;
__le16 UnparsedPathLength;
__le16 SubstituteNameOffset;
__le16 SubstituteNameLength;
__le16 PrintNameOffset;
__le16 PrintNameLength;
__le32 Flags;
__u8 PathBuffer[0];
} __packed;
#define SMB2_CLIENT_GUID_SIZE 16
extern __u8 cifs_client_guid[SMB2_CLIENT_GUID_SIZE];

3
fs/cifs/smb2proto.h

@ -106,7 +106,8 @@ extern int SMB2_tcon(const unsigned int xid, struct cifs_ses *ses,
extern int SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon);
extern int SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms,
__le16 *path, __u8 *oplock,
struct smb2_file_all_info *buf);
struct smb2_file_all_info *buf,
struct smb2_err_rsp **err_buf);
extern int SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon,
u64 persistent_fid, u64 volatile_fid, u32 opcode,
bool is_fsctl, char *in_data, u32 indatalen,

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