// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2018 Samsung Electronics Co., Ltd.
* Copyright (C) 2018 Namjae Jeon <[email protected]>
*/
#include <linux/user_namespace.h>
#include "smb_common.h"
#include "server.h"
#include "misc.h"
#include "../common/smb2status.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 mnt_idmap *idmap = file_mnt_idmap(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;
rc = ksmbd_vfs_fill_dentry_attrs(work,
idmap,
dentry,
&ksmbd_kstat);
if (rc)
break;
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 conforms 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.
*/
down_read(&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;
}
}
up_read(&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_share_config *share)
{
struct ksmbd_session *sess = work->sess;
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(&init_task);
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;
}
int ksmbd_override_fsids(struct ksmbd_work *work)
{
return __ksmbd_override_fsids(work, work->tcon->share_conf);
}
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;
}
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