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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>
hifive-unleashed-5.1
Pavel Shilovsky 2013-08-14 19:25:21 +04:00 committed by Steve French
parent 3ae35cde67
commit b42bf88828
11 changed files with 103 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fs/cifs/cifsglob.h
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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
View File

@ -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,