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/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,