misc.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) 2016 Namjae Jeon <linkinjeon@gmail.com>
 *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
 */

#include <linux/kernel.h>
#include <linux/version.h>
#include <linux/xattr.h>
#include <linux/fs.h>

#include "misc.h"
#include "smb_common.h"
#include "transport_tcp.h"
#include "vfs.h"

#include "mgmt/share_config.h"

/* @FIXME rework this code */

/**
 * dump_smb_msg() - print smb packet for debugging
 * @buf:		smb packet
 * @smb_buf_length:	packet print length
 *
 */
void dump_smb_msg(void *buf, int smb_buf_length)
{
	int i, j;
	char debug_line[33];
	unsigned char *buffer = buf;

	if (likely(cifsd_debugging != 2))
		return;

	for (i = 0, j = 0; i < smb_buf_length; i++, j++) {
		if (i % 16 == 0) {
			/* have reached the beginning of line */
			pr_err("%04x ", i);
			pr_cont("| ");
			j = 0;
		}

		pr_cont("%02x ", buffer[i]);
		debug_line[2 * j] = ' ';
		if (isprint(buffer[i]))
			debug_line[1 + (2 * j)] = buffer[i];
		else
			debug_line[1 + (2 * j)] = '_';

		if (i % 16 == 15) {
			/* reached end of line, time to print ascii */
			debug_line[32] = 0;
			pr_cont(" | %s\n", debug_line);
		}
	}
	for (; j < 16; j++) {
		pr_cont("   ");
		debug_line[2 * j] = ' ';
		debug_line[1 + (2 * j)] = ' ';
	}
	pr_cont(" | %s\n", debug_line);
}

/**
 * match_pattern() - compare a string with a pattern which might include
 * wildcard '*' and '?'
 * TODO : implement consideration about DOS_DOT, DOS_QM and DOS_STAR
 *
 * @string:	string to compare with a pattern
 * @pattern:	pattern string which might include wildcard '*' and '?'
 *
 * Return:	0 if pattern matched with the string, otherwise non zero value
 */
int match_pattern(const char *str, const char *pattern)
{
	const char *s = str;
	const char *p = pattern;
	bool star = false;

	while (*s) {
		switch (*p) {
		case '?':
			s++;
			p++;
			break;
		case '*':
			star = true;
			str = s;
			if (!*++p)
				return true;
			pattern = p;
			break;
		default:
			if (tolower(*s) == tolower(*p)) {
				s++;
				p++;
			} else {
				if (!star)
					return false;
				str++;
				s = str;
				p = pattern;
			}
			break;
		}
	}

	if (*p == '*')
		++p;
	return !*p;
}

/*
 * is_char_allowed() - check for valid character
 * @ch:		input character to be checked
 *
 * Return:	1 if char is allowed, otherwise 0
 */
static inline int is_char_allowed(char ch)
{
	/* check for control chars, wildcards etc. */
	if (!(ch & 0x80) &&
		(ch <= 0x1f ||
		 ch == '?' || ch == '"' || ch == '<' ||
		 ch == '>' || ch == '|' || ch == '*'))
		return 0;

	return 1;
}

int cifsd_validate_filename(char *filename)
{
	while (*filename) {
		char c = *filename;

		filename++;
		if (!is_char_allowed(c)) {
			cifsd_err("File name validation failed: 0x%x\n", c);
			return -ENOENT;
		}
	}

	return 0;
}

static int cifsd_validate_stream_name(char *stream_name)
{
	while (*stream_name) {
		char c = *stream_name;

		stream_name++;
		if (c == '/' || c == ':' || c == '\\') {
			cifsd_err("Stream name validation failed: %c\n", c);
			return -ENOENT;
		}
	}

	return 0;
}

int parse_stream_name(char *filename, char **stream_name, int *s_type)
{
	char *stream_type;
	char *s_name;
	int rc = 0;

	s_name = filename;
	filename = strsep(&s_name, ":");
	cifsd_debug("filename : %s, streams : %s\n", filename, s_name);
	if (strchr(s_name, ':')) {
		stream_type = s_name;
		s_name = strsep(&stream_type, ":");

		rc = cifsd_validate_stream_name(s_name);
		if (rc < 0) {
			rc = -ENOENT;
			goto out;
		}

		cifsd_debug("stream name : %s, stream type : %s\n", s_name,
				stream_type);
		if (!strncasecmp("$data", stream_type, 5))
			*s_type = DATA_STREAM;
		else if (!strncasecmp("$index_allocation", stream_type, 17))
			*s_type = DIR_STREAM;
		else
			rc = -ENOENT;
	}

	*stream_name = s_name;
out:
	return rc;
}

/**
 * convert_to_nt_pathname() - extract and return windows path string
 *      whose share directory prefix was removed from file path
 * @filename : unix filename
 * @sharepath: share path string
 *
 * Return : windows path string or error
 */

char *convert_to_nt_pathname(char *filename, char *sharepath)
{
	char *ab_pathname;
	int len;

	ab_pathname = kmalloc(strlen(filename), GFP_KERNEL);
	if (!ab_pathname)
		return NULL;

	ab_pathname[0] = '\\';
	ab_pathname[1] = '\0';

	len = strlen(sharepath);
	if (!strncmp(filename, sharepath, len) && strlen(filename) != len) {
		strcpy(ab_pathname, &filename[len]);
		cifsd_conv_path_to_windows(ab_pathname);
	}

	return ab_pathname;
}

int get_nlink(struct kstat *st)
{
	int nlink;

	nlink = st->nlink;
	if (S_ISDIR(st->mode))
		nlink--;

	return nlink;
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
static void strreplace(char *s, char old, char new)
{
	for (; *s; ++s)
		if (*s == old)
			*s = new;
}
#endif

void cifsd_conv_path_to_unix(char *path)
{
	strreplace(path, '\\', '/');
}

void cifsd_conv_path_to_windows(char *path)
{
	strreplace(path, '/', '\\');
}

/**
 * extract_sharename() - get share name from tree connect request
 * @treename:	buffer containing tree name and share name
 *
 * Return:      share name on success, otherwise error
 */
char *extract_sharename(char *treename)
{
	char *name = treename;
	char *dst;
	char *pos = strrchr(name, '\\');

	if (pos)
		name = (pos + 1);

	/* caller has to free the memory */
	dst = kstrdup(name, GFP_KERNEL);
	if (!dst)
		return ERR_PTR(-ENOMEM);
	return dst;
}

/**
 * convert_to_unix_name() - convert windows name to unix format
 * @path:	name to be converted
 * @tid:	tree id of mathing share
 *
 * Return:	converted name on success, otherwise NULL
 */
char *convert_to_unix_name(struct cifsd_share_config *share, char *name)
{
	int no_slash = 0, name_len, path_len;
	char *new_name;

	if (name[0] == '/')
		name++;

	path_len = share->path_sz;
	name_len = strlen(name);
	new_name = kmalloc(path_len + name_len + 2, GFP_KERNEL);
	if (!new_name)
		return new_name;

	memcpy(new_name, share->path, path_len);
	if (new_name[path_len - 1] != '/') {
		new_name[path_len] = '/';
		no_slash = 1;
	}

	memcpy(new_name + path_len + no_slash, name, name_len);
	path_len += name_len + no_slash;
	new_name[path_len] = 0x00;
	return new_name;
}

/**
 * convname_updatenextoffset() - convert name to UTF, update next_entry_offset
 * @namestr:            source filename buffer
 * @len:                source buffer length
 * @size:               used buffer size
 * @local_nls           code page table
 * @name_len:           file name length after conversion
 * @next_entry_offset:  offset of dentry
 * @buf_len:            response buffer length
 * @data_count:         used response buffer size
 * @no_namelen_field:	flag which shows if a namelen field flag exist
 *
 * Return:      return error if next entry could not fit in current response
 *              buffer, otherwise return encode buffer.
 */
char *convname_updatenextoffset(char *namestr, int len, int size,
		const struct nls_table *local_nls, int *name_len,
		int *next_entry_offset, int *buf_len, int *data_count,
		int alignment, bool no_namelen_field)
{
	char *enc_buf;

	enc_buf = kmalloc(PATH_MAX, GFP_KERNEL);
	if (!enc_buf)
		return NULL;

	*name_len = smbConvertToUTF16((__le16 *)enc_buf,
			namestr, len, local_nls, 0);
	*name_len *= 2;
	if (no_namelen_field) {
		enc_buf[*name_len] = '\0';
		enc_buf[*name_len+1] = '\0';
		*name_len += 2;
	}

	*next_entry_offset = (size - 1 + *name_len + alignment) & ~alignment;

	if (*next_entry_offset > *buf_len) {
		cifsd_debug("buf_len : %d next_entry_offset : %d"
				" data_count : %d\n", *buf_len,
				*next_entry_offset, *data_count);
		*buf_len = -1;
		kfree(enc_buf);
		return NULL;
	}
	return enc_buf;
}