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-rw-r--r--fs/smb/server/smb_common.c810
1 files changed, 810 insertions, 0 deletions
diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c
new file mode 100644
index 000000000..e90a1e8c1
--- /dev/null
+++ b/fs/smb/server/smb_common.c
@@ -0,0 +1,810 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ * Copyright (C) 2018 Namjae Jeon <linkinjeon@kernel.org>
+ */
+
+#include <linux/user_namespace.h>
+
+#include "smb_common.h"
+#include "server.h"
+#include "misc.h"
+#include "smbstatus.h"
+#include "connection.h"
+#include "ksmbd_work.h"
+#include "mgmt/user_session.h"
+#include "mgmt/user_config.h"
+#include "mgmt/tree_connect.h"
+#include "mgmt/share_config.h"
+
+/*for shortname implementation */
+static const char basechars[43] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_-!@#$%";
+#define MANGLE_BASE (sizeof(basechars) / sizeof(char) - 1)
+#define MAGIC_CHAR '~'
+#define PERIOD '.'
+#define mangle(V) ((char)(basechars[(V) % MANGLE_BASE]))
+
+struct smb_protocol {
+ int index;
+ char *name;
+ char *prot;
+ __u16 prot_id;
+};
+
+static struct smb_protocol smb1_protos[] = {
+ {
+ SMB21_PROT,
+ "\2SMB 2.1",
+ "SMB2_10",
+ SMB21_PROT_ID
+ },
+ {
+ SMB2X_PROT,
+ "\2SMB 2.???",
+ "SMB2_22",
+ SMB2X_PROT_ID
+ },
+};
+
+static struct smb_protocol smb2_protos[] = {
+ {
+ SMB21_PROT,
+ "\2SMB 2.1",
+ "SMB2_10",
+ SMB21_PROT_ID
+ },
+ {
+ SMB30_PROT,
+ "\2SMB 3.0",
+ "SMB3_00",
+ SMB30_PROT_ID
+ },
+ {
+ SMB302_PROT,
+ "\2SMB 3.02",
+ "SMB3_02",
+ SMB302_PROT_ID
+ },
+ {
+ SMB311_PROT,
+ "\2SMB 3.1.1",
+ "SMB3_11",
+ SMB311_PROT_ID
+ },
+};
+
+unsigned int ksmbd_server_side_copy_max_chunk_count(void)
+{
+ return 256;
+}
+
+unsigned int ksmbd_server_side_copy_max_chunk_size(void)
+{
+ return (2U << 30) - 1;
+}
+
+unsigned int ksmbd_server_side_copy_max_total_size(void)
+{
+ return (2U << 30) - 1;
+}
+
+inline int ksmbd_min_protocol(void)
+{
+ return SMB21_PROT;
+}
+
+inline int ksmbd_max_protocol(void)
+{
+ return SMB311_PROT;
+}
+
+int ksmbd_lookup_protocol_idx(char *str)
+{
+ int offt = ARRAY_SIZE(smb1_protos) - 1;
+ int len = strlen(str);
+
+ while (offt >= 0) {
+ if (!strncmp(str, smb1_protos[offt].prot, len)) {
+ ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
+ smb1_protos[offt].prot, offt);
+ return smb1_protos[offt].index;
+ }
+ offt--;
+ }
+
+ offt = ARRAY_SIZE(smb2_protos) - 1;
+ while (offt >= 0) {
+ if (!strncmp(str, smb2_protos[offt].prot, len)) {
+ ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
+ smb2_protos[offt].prot, offt);
+ return smb2_protos[offt].index;
+ }
+ offt--;
+ }
+ return -1;
+}
+
+/**
+ * ksmbd_verify_smb_message() - check for valid smb2 request header
+ * @work: smb work
+ *
+ * check for valid smb signature and packet direction(request/response)
+ *
+ * Return: 0 on success, otherwise -EINVAL
+ */
+int ksmbd_verify_smb_message(struct ksmbd_work *work)
+{
+ struct smb2_hdr *smb2_hdr = ksmbd_req_buf_next(work);
+ struct smb_hdr *hdr;
+
+ if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER)
+ return ksmbd_smb2_check_message(work);
+
+ hdr = work->request_buf;
+ if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
+ hdr->Command == SMB_COM_NEGOTIATE) {
+ work->conn->outstanding_credits++;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+/**
+ * ksmbd_smb_request() - check for valid smb request type
+ * @conn: connection instance
+ *
+ * Return: true on success, otherwise false
+ */
+bool ksmbd_smb_request(struct ksmbd_conn *conn)
+{
+ __le32 *proto;
+
+ if (conn->request_buf[0] != 0)
+ return false;
+
+ proto = (__le32 *)smb2_get_msg(conn->request_buf);
+ if (*proto == SMB2_COMPRESSION_TRANSFORM_ID) {
+ pr_err_ratelimited("smb2 compression not support yet");
+ return false;
+ }
+
+ if (*proto != SMB1_PROTO_NUMBER &&
+ *proto != SMB2_PROTO_NUMBER &&
+ *proto != SMB2_TRANSFORM_PROTO_NUM)
+ return false;
+
+ return true;
+}
+
+static bool supported_protocol(int idx)
+{
+ if (idx == SMB2X_PROT &&
+ (server_conf.min_protocol >= SMB21_PROT ||
+ server_conf.max_protocol <= SMB311_PROT))
+ return true;
+
+ return (server_conf.min_protocol <= idx &&
+ idx <= server_conf.max_protocol);
+}
+
+static char *next_dialect(char *dialect, int *next_off, int bcount)
+{
+ dialect = dialect + *next_off;
+ *next_off = strnlen(dialect, bcount);
+ if (dialect[*next_off] != '\0')
+ return NULL;
+ return dialect;
+}
+
+static int ksmbd_lookup_dialect_by_name(char *cli_dialects, __le16 byte_count)
+{
+ int i, seq_num, bcount, next;
+ char *dialect;
+
+ for (i = ARRAY_SIZE(smb1_protos) - 1; i >= 0; i--) {
+ seq_num = 0;
+ next = 0;
+ dialect = cli_dialects;
+ bcount = le16_to_cpu(byte_count);
+ do {
+ dialect = next_dialect(dialect, &next, bcount);
+ if (!dialect)
+ break;
+ ksmbd_debug(SMB, "client requested dialect %s\n",
+ dialect);
+ if (!strcmp(dialect, smb1_protos[i].name)) {
+ if (supported_protocol(smb1_protos[i].index)) {
+ ksmbd_debug(SMB,
+ "selected %s dialect\n",
+ smb1_protos[i].name);
+ if (smb1_protos[i].index == SMB1_PROT)
+ return seq_num;
+ return smb1_protos[i].prot_id;
+ }
+ }
+ seq_num++;
+ bcount -= (++next);
+ } while (bcount > 0);
+ }
+
+ return BAD_PROT_ID;
+}
+
+int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
+{
+ int i;
+ int count;
+
+ for (i = ARRAY_SIZE(smb2_protos) - 1; i >= 0; i--) {
+ count = le16_to_cpu(dialects_count);
+ while (--count >= 0) {
+ ksmbd_debug(SMB, "client requested dialect 0x%x\n",
+ le16_to_cpu(cli_dialects[count]));
+ if (le16_to_cpu(cli_dialects[count]) !=
+ smb2_protos[i].prot_id)
+ continue;
+
+ if (supported_protocol(smb2_protos[i].index)) {
+ ksmbd_debug(SMB, "selected %s dialect\n",
+ smb2_protos[i].name);
+ return smb2_protos[i].prot_id;
+ }
+ }
+ }
+
+ return BAD_PROT_ID;
+}
+
+static int ksmbd_negotiate_smb_dialect(void *buf)
+{
+ int smb_buf_length = get_rfc1002_len(buf);
+ __le32 proto = ((struct smb2_hdr *)smb2_get_msg(buf))->ProtocolId;
+
+ if (proto == SMB2_PROTO_NUMBER) {
+ struct smb2_negotiate_req *req;
+ int smb2_neg_size =
+ offsetof(struct smb2_negotiate_req, Dialects);
+
+ req = (struct smb2_negotiate_req *)smb2_get_msg(buf);
+ if (smb2_neg_size > smb_buf_length)
+ goto err_out;
+
+ if (struct_size(req, Dialects, le16_to_cpu(req->DialectCount)) >
+ smb_buf_length)
+ goto err_out;
+
+ return ksmbd_lookup_dialect_by_id(req->Dialects,
+ req->DialectCount);
+ }
+
+ proto = *(__le32 *)((struct smb_hdr *)buf)->Protocol;
+ if (proto == SMB1_PROTO_NUMBER) {
+ struct smb_negotiate_req *req;
+
+ req = (struct smb_negotiate_req *)buf;
+ if (le16_to_cpu(req->ByteCount) < 2)
+ goto err_out;
+
+ if (offsetof(struct smb_negotiate_req, DialectsArray) - 4 +
+ le16_to_cpu(req->ByteCount) > smb_buf_length) {
+ goto err_out;
+ }
+
+ return ksmbd_lookup_dialect_by_name(req->DialectsArray,
+ req->ByteCount);
+ }
+
+err_out:
+ return BAD_PROT_ID;
+}
+
+#define SMB_COM_NEGOTIATE_EX 0x0
+
+/**
+ * get_smb1_cmd_val() - get smb command value from smb header
+ * @work: smb work containing smb header
+ *
+ * Return: smb command value
+ */
+static u16 get_smb1_cmd_val(struct ksmbd_work *work)
+{
+ return SMB_COM_NEGOTIATE_EX;
+}
+
+/**
+ * init_smb1_rsp_hdr() - initialize smb negotiate response header
+ * @work: smb work containing smb request
+ *
+ * Return: 0 on success, otherwise -EINVAL
+ */
+static int init_smb1_rsp_hdr(struct ksmbd_work *work)
+{
+ struct smb_hdr *rsp_hdr = (struct smb_hdr *)work->response_buf;
+ struct smb_hdr *rcv_hdr = (struct smb_hdr *)work->request_buf;
+
+ rsp_hdr->Command = SMB_COM_NEGOTIATE;
+ *(__le32 *)rsp_hdr->Protocol = SMB1_PROTO_NUMBER;
+ rsp_hdr->Flags = SMBFLG_RESPONSE;
+ rsp_hdr->Flags2 = SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS |
+ SMBFLG2_EXT_SEC | SMBFLG2_IS_LONG_NAME;
+ rsp_hdr->Pid = rcv_hdr->Pid;
+ rsp_hdr->Mid = rcv_hdr->Mid;
+ return 0;
+}
+
+/**
+ * smb1_check_user_session() - check for valid session for a user
+ * @work: smb work containing smb request buffer
+ *
+ * Return: 0 on success, otherwise error
+ */
+static int smb1_check_user_session(struct ksmbd_work *work)
+{
+ unsigned int cmd = work->conn->ops->get_cmd_val(work);
+
+ if (cmd == SMB_COM_NEGOTIATE_EX)
+ return 0;
+
+ return -EINVAL;
+}
+
+/**
+ * smb1_allocate_rsp_buf() - allocate response buffer for a command
+ * @work: smb work containing smb request
+ *
+ * Return: 0 on success, otherwise -ENOMEM
+ */
+static int smb1_allocate_rsp_buf(struct ksmbd_work *work)
+{
+ work->response_buf = kzalloc(MAX_CIFS_SMALL_BUFFER_SIZE,
+ GFP_KERNEL);
+ work->response_sz = MAX_CIFS_SMALL_BUFFER_SIZE;
+
+ if (!work->response_buf) {
+ pr_err("Failed to allocate %u bytes buffer\n",
+ MAX_CIFS_SMALL_BUFFER_SIZE);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/**
+ * set_smb1_rsp_status() - set error type in smb response header
+ * @work: smb work containing smb response header
+ * @err: error code to set in response
+ */
+static void set_smb1_rsp_status(struct ksmbd_work *work, __le32 err)
+{
+ work->send_no_response = 1;
+}
+
+static struct smb_version_ops smb1_server_ops = {
+ .get_cmd_val = get_smb1_cmd_val,
+ .init_rsp_hdr = init_smb1_rsp_hdr,
+ .allocate_rsp_buf = smb1_allocate_rsp_buf,
+ .check_user_session = smb1_check_user_session,
+ .set_rsp_status = set_smb1_rsp_status,
+};
+
+static int smb1_negotiate(struct ksmbd_work *work)
+{
+ return ksmbd_smb_negotiate_common(work, SMB_COM_NEGOTIATE);
+}
+
+static struct smb_version_cmds smb1_server_cmds[1] = {
+ [SMB_COM_NEGOTIATE_EX] = { .proc = smb1_negotiate, },
+};
+
+static int init_smb1_server(struct ksmbd_conn *conn)
+{
+ conn->ops = &smb1_server_ops;
+ conn->cmds = smb1_server_cmds;
+ conn->max_cmds = ARRAY_SIZE(smb1_server_cmds);
+ return 0;
+}
+
+int ksmbd_init_smb_server(struct ksmbd_work *work)
+{
+ struct ksmbd_conn *conn = work->conn;
+ __le32 proto;
+
+ proto = *(__le32 *)((struct smb_hdr *)work->request_buf)->Protocol;
+ if (conn->need_neg == false) {
+ if (proto == SMB1_PROTO_NUMBER)
+ return -EINVAL;
+ return 0;
+ }
+
+ if (proto == SMB1_PROTO_NUMBER)
+ return init_smb1_server(conn);
+ return init_smb3_11_server(conn);
+}
+
+int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
+ struct ksmbd_file *dir,
+ struct ksmbd_dir_info *d_info,
+ char *search_pattern,
+ int (*fn)(struct ksmbd_conn *, int,
+ struct ksmbd_dir_info *,
+ struct ksmbd_kstat *))
+{
+ int i, rc = 0;
+ struct ksmbd_conn *conn = work->conn;
+ struct user_namespace *user_ns = file_mnt_user_ns(dir->filp);
+
+ for (i = 0; i < 2; i++) {
+ struct kstat kstat;
+ struct ksmbd_kstat ksmbd_kstat;
+ struct dentry *dentry;
+
+ if (!dir->dot_dotdot[i]) { /* fill dot entry info */
+ if (i == 0) {
+ d_info->name = ".";
+ d_info->name_len = 1;
+ dentry = dir->filp->f_path.dentry;
+ } else {
+ d_info->name = "..";
+ d_info->name_len = 2;
+ dentry = dir->filp->f_path.dentry->d_parent;
+ }
+
+ if (!match_pattern(d_info->name, d_info->name_len,
+ search_pattern)) {
+ dir->dot_dotdot[i] = 1;
+ continue;
+ }
+
+ ksmbd_kstat.kstat = &kstat;
+ ksmbd_vfs_fill_dentry_attrs(work,
+ user_ns,
+ dentry,
+ &ksmbd_kstat);
+ rc = fn(conn, info_level, d_info, &ksmbd_kstat);
+ if (rc)
+ break;
+ if (d_info->out_buf_len <= 0)
+ break;
+
+ dir->dot_dotdot[i] = 1;
+ if (d_info->flags & SMB2_RETURN_SINGLE_ENTRY) {
+ d_info->out_buf_len = 0;
+ break;
+ }
+ }
+ }
+
+ return rc;
+}
+
+/**
+ * ksmbd_extract_shortname() - get shortname from long filename
+ * @conn: connection instance
+ * @longname: source long filename
+ * @shortname: destination short filename
+ *
+ * Return: shortname length or 0 when source long name is '.' or '..'
+ * TODO: Though this function comforms the restriction of 8.3 Filename spec,
+ * but the result is different with Windows 7's one. need to check.
+ */
+int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
+ char *shortname)
+{
+ const char *p;
+ char base[9], extension[4];
+ char out[13] = {0};
+ int baselen = 0;
+ int extlen = 0, len = 0;
+ unsigned int csum = 0;
+ const unsigned char *ptr;
+ bool dot_present = true;
+
+ p = longname;
+ if ((*p == '.') || (!(strcmp(p, "..")))) {
+ /*no mangling required */
+ return 0;
+ }
+
+ p = strrchr(longname, '.');
+ if (p == longname) { /*name starts with a dot*/
+ strscpy(extension, "___", strlen("___"));
+ } else {
+ if (p) {
+ p++;
+ while (*p && extlen < 3) {
+ if (*p != '.')
+ extension[extlen++] = toupper(*p);
+ p++;
+ }
+ extension[extlen] = '\0';
+ } else {
+ dot_present = false;
+ }
+ }
+
+ p = longname;
+ if (*p == '.') {
+ p++;
+ longname++;
+ }
+ while (*p && (baselen < 5)) {
+ if (*p != '.')
+ base[baselen++] = toupper(*p);
+ p++;
+ }
+
+ base[baselen] = MAGIC_CHAR;
+ memcpy(out, base, baselen + 1);
+
+ ptr = longname;
+ len = strlen(longname);
+ for (; len > 0; len--, ptr++)
+ csum += *ptr;
+
+ csum = csum % (MANGLE_BASE * MANGLE_BASE);
+ out[baselen + 1] = mangle(csum / MANGLE_BASE);
+ out[baselen + 2] = mangle(csum);
+ out[baselen + 3] = PERIOD;
+
+ if (dot_present)
+ memcpy(out + baselen + 4, extension, 4);
+ else
+ out[baselen + 4] = '\0';
+ smbConvertToUTF16((__le16 *)shortname, out, PATH_MAX,
+ conn->local_nls, 0);
+ len = strlen(out) * 2;
+ return len;
+}
+
+static int __smb2_negotiate(struct ksmbd_conn *conn)
+{
+ return (conn->dialect >= SMB20_PROT_ID &&
+ conn->dialect <= SMB311_PROT_ID);
+}
+
+static int smb_handle_negotiate(struct ksmbd_work *work)
+{
+ struct smb_negotiate_rsp *neg_rsp = work->response_buf;
+
+ ksmbd_debug(SMB, "Unsupported SMB1 protocol\n");
+
+ if (ksmbd_iov_pin_rsp(work, (void *)neg_rsp,
+ sizeof(struct smb_negotiate_rsp) - 4))
+ return -ENOMEM;
+
+ neg_rsp->hdr.Status.CifsError = STATUS_SUCCESS;
+ neg_rsp->hdr.WordCount = 1;
+ neg_rsp->DialectIndex = cpu_to_le16(work->conn->dialect);
+ neg_rsp->ByteCount = 0;
+ return 0;
+}
+
+int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
+{
+ struct ksmbd_conn *conn = work->conn;
+ int ret;
+
+ conn->dialect =
+ ksmbd_negotiate_smb_dialect(work->request_buf);
+ ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
+
+ if (command == SMB2_NEGOTIATE_HE) {
+ ret = smb2_handle_negotiate(work);
+ return ret;
+ }
+
+ if (command == SMB_COM_NEGOTIATE) {
+ if (__smb2_negotiate(conn)) {
+ init_smb3_11_server(conn);
+ init_smb2_neg_rsp(work);
+ ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
+ return 0;
+ }
+ return smb_handle_negotiate(work);
+ }
+
+ pr_err("Unknown SMB negotiation command: %u\n", command);
+ return -EINVAL;
+}
+
+enum SHARED_MODE_ERRORS {
+ SHARE_DELETE_ERROR,
+ SHARE_READ_ERROR,
+ SHARE_WRITE_ERROR,
+ FILE_READ_ERROR,
+ FILE_WRITE_ERROR,
+ FILE_DELETE_ERROR,
+};
+
+static const char * const shared_mode_errors[] = {
+ "Current access mode does not permit SHARE_DELETE",
+ "Current access mode does not permit SHARE_READ",
+ "Current access mode does not permit SHARE_WRITE",
+ "Desired access mode does not permit FILE_READ",
+ "Desired access mode does not permit FILE_WRITE",
+ "Desired access mode does not permit FILE_DELETE",
+};
+
+static void smb_shared_mode_error(int error, struct ksmbd_file *prev_fp,
+ struct ksmbd_file *curr_fp)
+{
+ ksmbd_debug(SMB, "%s\n", shared_mode_errors[error]);
+ ksmbd_debug(SMB, "Current mode: 0x%x Desired mode: 0x%x\n",
+ prev_fp->saccess, curr_fp->daccess);
+}
+
+int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
+{
+ int rc = 0;
+ struct ksmbd_file *prev_fp;
+
+ /*
+ * Lookup fp in master fp list, and check desired access and
+ * shared mode between previous open and current open.
+ */
+ read_lock(&curr_fp->f_ci->m_lock);
+ list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
+ if (file_inode(filp) != file_inode(prev_fp->filp))
+ continue;
+
+ if (filp == prev_fp->filp)
+ continue;
+
+ if (ksmbd_stream_fd(prev_fp) && ksmbd_stream_fd(curr_fp))
+ if (strcmp(prev_fp->stream.name, curr_fp->stream.name))
+ continue;
+
+ if (prev_fp->attrib_only != curr_fp->attrib_only)
+ continue;
+
+ if (!(prev_fp->saccess & FILE_SHARE_DELETE_LE) &&
+ curr_fp->daccess & FILE_DELETE_LE) {
+ smb_shared_mode_error(SHARE_DELETE_ERROR,
+ prev_fp,
+ curr_fp);
+ rc = -EPERM;
+ break;
+ }
+
+ /*
+ * Only check FILE_SHARE_DELETE if stream opened and
+ * normal file opened.
+ */
+ if (ksmbd_stream_fd(prev_fp) && !ksmbd_stream_fd(curr_fp))
+ continue;
+
+ if (!(prev_fp->saccess & FILE_SHARE_READ_LE) &&
+ curr_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE)) {
+ smb_shared_mode_error(SHARE_READ_ERROR,
+ prev_fp,
+ curr_fp);
+ rc = -EPERM;
+ break;
+ }
+
+ if (!(prev_fp->saccess & FILE_SHARE_WRITE_LE) &&
+ curr_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) {
+ smb_shared_mode_error(SHARE_WRITE_ERROR,
+ prev_fp,
+ curr_fp);
+ rc = -EPERM;
+ break;
+ }
+
+ if (prev_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE) &&
+ !(curr_fp->saccess & FILE_SHARE_READ_LE)) {
+ smb_shared_mode_error(FILE_READ_ERROR,
+ prev_fp,
+ curr_fp);
+ rc = -EPERM;
+ break;
+ }
+
+ if (prev_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE) &&
+ !(curr_fp->saccess & FILE_SHARE_WRITE_LE)) {
+ smb_shared_mode_error(FILE_WRITE_ERROR,
+ prev_fp,
+ curr_fp);
+ rc = -EPERM;
+ break;
+ }
+
+ if (prev_fp->daccess & FILE_DELETE_LE &&
+ !(curr_fp->saccess & FILE_SHARE_DELETE_LE)) {
+ smb_shared_mode_error(FILE_DELETE_ERROR,
+ prev_fp,
+ curr_fp);
+ rc = -EPERM;
+ break;
+ }
+ }
+ read_unlock(&curr_fp->f_ci->m_lock);
+
+ return rc;
+}
+
+bool is_asterisk(char *p)
+{
+ return p && p[0] == '*';
+}
+
+int ksmbd_override_fsids(struct ksmbd_work *work)
+{
+ struct ksmbd_session *sess = work->sess;
+ struct ksmbd_share_config *share = work->tcon->share_conf;
+ struct cred *cred;
+ struct group_info *gi;
+ unsigned int uid;
+ unsigned int gid;
+
+ uid = user_uid(sess->user);
+ gid = user_gid(sess->user);
+ if (share->force_uid != KSMBD_SHARE_INVALID_UID)
+ uid = share->force_uid;
+ if (share->force_gid != KSMBD_SHARE_INVALID_GID)
+ gid = share->force_gid;
+
+ cred = prepare_kernel_cred(NULL);
+ if (!cred)
+ return -ENOMEM;
+
+ cred->fsuid = make_kuid(&init_user_ns, uid);
+ cred->fsgid = make_kgid(&init_user_ns, gid);
+
+ gi = groups_alloc(0);
+ if (!gi) {
+ abort_creds(cred);
+ return -ENOMEM;
+ }
+ set_groups(cred, gi);
+ put_group_info(gi);
+
+ if (!uid_eq(cred->fsuid, GLOBAL_ROOT_UID))
+ cred->cap_effective = cap_drop_fs_set(cred->cap_effective);
+
+ WARN_ON(work->saved_cred);
+ work->saved_cred = override_creds(cred);
+ if (!work->saved_cred) {
+ abort_creds(cred);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+void ksmbd_revert_fsids(struct ksmbd_work *work)
+{
+ const struct cred *cred;
+
+ WARN_ON(!work->saved_cred);
+
+ cred = current_cred();
+ revert_creds(work->saved_cred);
+ put_cred(cred);
+ work->saved_cred = NULL;
+}
+
+__le32 smb_map_generic_desired_access(__le32 daccess)
+{
+ if (daccess & FILE_GENERIC_READ_LE) {
+ daccess |= cpu_to_le32(GENERIC_READ_FLAGS);
+ daccess &= ~FILE_GENERIC_READ_LE;
+ }
+
+ if (daccess & FILE_GENERIC_WRITE_LE) {
+ daccess |= cpu_to_le32(GENERIC_WRITE_FLAGS);
+ daccess &= ~FILE_GENERIC_WRITE_LE;
+ }
+
+ if (daccess & FILE_GENERIC_EXECUTE_LE) {
+ daccess |= cpu_to_le32(GENERIC_EXECUTE_FLAGS);
+ daccess &= ~FILE_GENERIC_EXECUTE_LE;
+ }
+
+ if (daccess & FILE_GENERIC_ALL_LE) {
+ daccess |= cpu_to_le32(GENERIC_ALL_FLAGS);
+ daccess &= ~FILE_GENERIC_ALL_LE;
+ }
+
+ return daccess;
+}