Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) /* Key type used to cache DNS lookups made by the kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * See Documentation/networking/dns_resolver.rst
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *   Copyright (c) 2007 Igor Mammedov
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *   Author(s): Igor Mammedov (niallain@gmail.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *              Steve French (sfrench@us.ibm.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *              Wang Lei (wang840925@gmail.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *		David Howells (dhowells@redhat.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  *   This library is free software; you can redistribute it and/or modify
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  *   it under the terms of the GNU Lesser General Public License as published
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  *   by the Free Software Foundation; either version 2.1 of the License, or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  *   (at your option) any later version.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  *   This library is distributed in the hope that it will be useful,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *   the GNU Lesser General Public License for more details.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  *   You should have received a copy of the GNU Lesser General Public License
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  *   along with this library; if not, see <http://www.gnu.org/licenses/>.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #include <linux/moduleparam.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include <linux/keyctl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) #include <linux/err.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #include <linux/seq_file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) #include <linux/dns_resolver.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) #include <keys/dns_resolver-type.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) #include <keys/user-type.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) MODULE_DESCRIPTION("DNS Resolver");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) MODULE_AUTHOR("Wang Lei");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) MODULE_LICENSE("GPL");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) unsigned int dns_resolver_debug;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) module_param_named(debug, dns_resolver_debug, uint, 0644);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) MODULE_PARM_DESC(debug, "DNS Resolver debugging mask");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) const struct cred *dns_resolver_cache;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) #define	DNS_ERRORNO_OPTION	"dnserror"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50)  * Preparse instantiation data for a dns_resolver key.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52)  * For normal hostname lookups, the data must be a NUL-terminated string, with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53)  * the NUL char accounted in datalen.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55)  * If the data contains a '#' characters, then we take the clause after each
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56)  * one to be an option of the form 'key=value'.  The actual data of interest is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57)  * the string leading up to the first '#'.  For instance:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59)  *        "ip1,ip2,...#foo=bar"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61)  * For server list requests, the data must begin with a NUL char and be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62)  * followed by a byte indicating the version of the data format.  Version 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63)  * looks something like (note this is packed):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65)  *	u8      Non-string marker (ie. 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66)  *	u8	Content (DNS_PAYLOAD_IS_*)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67)  *	u8	Version (e.g. 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68)  *	u8	Source of server list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69)  *	u8	Lookup status of server list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70)  *	u8	Number of servers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  *	foreach-server {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72)  *		__le16	Name length
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73)  *		__le16	Priority (as per SRV record, low first)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)  *		__le16	Weight (as per SRV record, higher first)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  *		__le16	Port
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  *		u8	Source of address list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  *		u8	Lookup status of address list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78)  *		u8	Protocol (DNS_SERVER_PROTOCOL_*)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79)  *		u8	Number of addresses
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80)  *		char[]	Name (not NUL-terminated)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81)  *		foreach-address {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82)  *			u8		Family (DNS_ADDRESS_IS_*)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83)  *			union {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)  *				u8[4]	ipv4_addr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85)  *				u8[16]	ipv6_addr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86)  *			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87)  *		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88)  *	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) dns_resolver_preparse(struct key_preparsed_payload *prep)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	const struct dns_payload_header *bin;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	struct user_key_payload *upayload;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	unsigned long derrno;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	int datalen = prep->datalen, result_len = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	const char *data = prep->data, *end, *opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	if (datalen <= 1 || !data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	if (data[0] == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		/* It may be a server list. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 		if (datalen <= sizeof(*bin))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 			return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		bin = (const struct dns_payload_header *)data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		kenter("[%u,%u],%u", bin->content, bin->version, datalen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 			pr_warn_ratelimited(
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 				"dns_resolver: Unsupported content type (%u)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 				bin->content);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 			return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 		if (bin->version != 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 			pr_warn_ratelimited(
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 				"dns_resolver: Unsupported server list version (%u)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 				bin->version);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 			return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 		result_len = datalen;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		goto store_result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	kenter("'%*.*s',%u", datalen, datalen, data, datalen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	if (!data || data[datalen - 1] != '\0')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	datalen--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	/* deal with any options embedded in the data */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	end = data + datalen;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	opt = memchr(data, '#', datalen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	if (!opt) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		/* no options: the entire data is the result */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		kdebug("no options");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		result_len = datalen;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		const char *next_opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		result_len = opt - data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		opt++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		kdebug("options: '%s'", opt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 			int opt_len, opt_nlen;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 			const char *eq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 			char optval[128];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			next_opt = memchr(opt, '#', end - opt) ?: end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 			opt_len = next_opt - opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 			if (opt_len <= 0 || opt_len > sizeof(optval)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 				pr_warn_ratelimited("Invalid option length (%d) for dns_resolver key\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 						    opt_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 				return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 			eq = memchr(opt, '=', opt_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 			if (eq) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 				opt_nlen = eq - opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 				eq++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 				memcpy(optval, eq, next_opt - eq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 				optval[next_opt - eq] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 			} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 				opt_nlen = opt_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 				optval[0] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 			kdebug("option '%*.*s' val '%s'",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 			       opt_nlen, opt_nlen, opt, optval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 			/* see if it's an error number representing a DNS error
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 			 * that's to be recorded as the result in this key */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 			if (opt_nlen == sizeof(DNS_ERRORNO_OPTION) - 1 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 			    memcmp(opt, DNS_ERRORNO_OPTION, opt_nlen) == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 				kdebug("dns error number option");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 				ret = kstrtoul(optval, 10, &derrno);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 				if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 					goto bad_option_value;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 				if (derrno < 1 || derrno > 511)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 					goto bad_option_value;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 				kdebug("dns error no. = %lu", derrno);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 				prep->payload.data[dns_key_error] = ERR_PTR(-derrno);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 				continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		bad_option_value:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 			pr_warn_ratelimited("Option '%*.*s' to dns_resolver key: bad/missing value\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 					    opt_nlen, opt_nlen, opt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		} while (opt = next_opt + 1, opt < end);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	/* don't cache the result if we're caching an error saying there's no
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	 * result */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	if (prep->payload.data[dns_key_error]) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		kleave(" = 0 [h_error %ld]", PTR_ERR(prep->payload.data[dns_key_error]));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) store_result:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	kdebug("store result");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	prep->quotalen = result_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	upayload = kmalloc(sizeof(*upayload) + result_len + 1, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	if (!upayload) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 		kleave(" = -ENOMEM");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	upayload->datalen = result_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	memcpy(upayload->data, data, result_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	upayload->data[result_len] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	prep->payload.data[dns_key_data] = upayload;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	kleave(" = 0");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)  * Clean up the preparse data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) static void dns_resolver_free_preparse(struct key_preparsed_payload *prep)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	pr_devel("==>%s()\n", __func__);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 	kfree(prep->payload.data[dns_key_data]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237)  * The description is of the form "[<type>:]<domain_name>"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)  * The domain name may be a simple name or an absolute domain name (which
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)  * should end with a period).  The domain name is case-independent.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) static bool dns_resolver_cmp(const struct key *key,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 			     const struct key_match_data *match_data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	int slen, dlen, ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	const char *src = key->description, *dsp = match_data->raw_data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	kenter("%s,%s", src, dsp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	if (!src || !dsp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 		goto no_match;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	if (strcasecmp(src, dsp) == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 		goto matched;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	slen = strlen(src);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	dlen = strlen(dsp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	if (slen <= 0 || dlen <= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 		goto no_match;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	if (src[slen - 1] == '.')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 		slen--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	if (dsp[dlen - 1] == '.')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		dlen--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	if (slen != dlen || strncasecmp(src, dsp, slen) != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 		goto no_match;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) matched:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	ret = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) no_match:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	kleave(" = %d", ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275)  * Preparse the match criterion.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) static int dns_resolver_match_preparse(struct key_match_data *match_data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 	match_data->cmp = dns_resolver_cmp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285)  * Describe a DNS key
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) static void dns_resolver_describe(const struct key *key, struct seq_file *m)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	seq_puts(m, key->description);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	if (key_is_positive(key)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		int err = PTR_ERR(key->payload.data[dns_key_error]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 		if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 			seq_printf(m, ": %d", err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 			seq_printf(m, ": %u", key->datalen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301)  * read the DNS data
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302)  * - the key's semaphore is read-locked
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) static long dns_resolver_read(const struct key *key,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 			      char *buffer, size_t buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	int err = PTR_ERR(key->payload.data[dns_key_error]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 		return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	return user_read(key, buffer, buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) struct key_type key_type_dns_resolver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	.name		= "dns_resolver",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	.flags		= KEY_TYPE_NET_DOMAIN,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 	.preparse	= dns_resolver_preparse,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	.free_preparse	= dns_resolver_free_preparse,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	.instantiate	= generic_key_instantiate,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 	.match_preparse	= dns_resolver_match_preparse,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 	.revoke		= user_revoke,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	.destroy	= user_destroy,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 	.describe	= dns_resolver_describe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 	.read		= dns_resolver_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) static int __init init_dns_resolver(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	struct cred *cred;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 	struct key *keyring;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	/* create an override credential set with a special thread keyring in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	 * which DNS requests are cached
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	 * this is used to prevent malicious redirections from being installed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	 * with add_key().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 	cred = prepare_kernel_cred(NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 	if (!cred)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 	keyring = keyring_alloc(".dns_resolver",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 				KEY_USR_VIEW | KEY_USR_READ,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 				KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 	if (IS_ERR(keyring)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 		ret = PTR_ERR(keyring);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 		goto failed_put_cred;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 	ret = register_key_type(&key_type_dns_resolver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 		goto failed_put_key;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 	/* instruct request_key() to use this special keyring as a cache for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 	 * the results it looks up */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 	set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 	cred->thread_keyring = keyring;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 	cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 	dns_resolver_cache = cred;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) 	kdebug("DNS resolver keyring: %d\n", key_serial(keyring));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) failed_put_key:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 	key_put(keyring);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) failed_put_cred:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 	put_cred(cred);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) static void __exit exit_dns_resolver(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 	key_revoke(dns_resolver_cache->thread_keyring);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) 	unregister_key_type(&key_type_dns_resolver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 	put_cred(dns_resolver_cache);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) module_init(init_dns_resolver)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) module_exit(exit_dns_resolver)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) MODULE_LICENSE("GPL");