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>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 52ca861..ec6c3fb 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -308,6 +308,9 @@
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 *);
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 449b6cf..ec0f342 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -549,6 +549,10 @@
* 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;
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 562044f..7e36ceb 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -509,6 +509,7 @@
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 @@
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 @@
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:
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 69d2c82..42ef03b 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -172,6 +172,9 @@
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;
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index 04a81a4..020245d 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -86,7 +86,7 @@
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;
diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
index c6ec163..78ff88c 100644
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -60,7 +60,7 @@
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 @@
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 @@
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
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index b0c4334..6103359 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -171,6 +171,10 @@
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;
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index f259e6c..91b9e54 100644
--- a/fs/cifs/smb2ops.c
+++ b/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 @@
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 @@
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 @@
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 @@
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 @@
.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 @@
.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,
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index abc9c28..5a49861 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -977,7 +977,8 @@
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 @@
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;
}
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 36b0d37..40baeae 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -150,6 +150,20 @@
__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];
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 1a5ecbe..1db89fd 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -106,7 +106,8 @@
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,