| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Wang Lei | 764 | 54.77% | 2 | 5.00% |
| David Howells | 448 | 32.11% | 20 | 50.00% |
| Steve French | 70 | 5.02% | 4 | 10.00% |
| Eric Biggers | 61 | 4.37% | 2 | 5.00% |
| Edward Adam Davis | 21 | 1.51% | 1 | 2.50% |
| Linus Torvalds | 9 | 0.65% | 1 | 2.50% |
| Jeff Layton | 5 | 0.36% | 1 | 2.50% |
| Thorsten Blum | 4 | 0.29% | 1 | 2.50% |
| Stephen Rothwell | 3 | 0.22% | 1 | 2.50% |
| Eric W. Biedermann | 2 | 0.14% | 1 | 2.50% |
| Bird, Timothy | 2 | 0.14% | 1 | 2.50% |
| Kees Cook | 2 | 0.14% | 1 | 2.50% |
| “Cosmin | 1 | 0.07% | 1 | 2.50% |
| Joe Perches | 1 | 0.07% | 1 | 2.50% |
| Shirish Pargaonkar | 1 | 0.07% | 1 | 2.50% |
| Eric Dumazet | 1 | 0.07% | 1 | 2.50% |
| Total | 1395 | 40 |
// SPDX-License-Identifier: LGPL-2.1-or-later /* Key type used to cache DNS lookups made by the kernel * * See Documentation/networking/dns_resolver.rst * * Copyright (c) 2007 Igor Mammedov * Author(s): Igor Mammedov (niallain@gmail.com) * Steve French (sfrench@us.ibm.com) * Wang Lei (wang840925@gmail.com) * David Howells (dhowells@redhat.com) */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/kernel.h> #include <linux/keyctl.h> #include <linux/err.h> #include <linux/seq_file.h> #include <linux/dns_resolver.h> #include <keys/dns_resolver-type.h> #include <keys/user-type.h> #include "internal.h" MODULE_DESCRIPTION("DNS Resolver"); MODULE_AUTHOR("Wang Lei"); MODULE_LICENSE("GPL"); unsigned int dns_resolver_debug; module_param_named(debug, dns_resolver_debug, uint, 0644); MODULE_PARM_DESC(debug, "DNS Resolver debugging mask"); const struct cred *dns_resolver_cache; #define DNS_ERRORNO_OPTION "dnserror" /* * Preparse instantiation data for a dns_resolver key. * * For normal hostname lookups, the data must be a NUL-terminated string, with * the NUL char accounted in datalen. * * If the data contains a '#' characters, then we take the clause after each * one to be an option of the form 'key=value'. The actual data of interest is * the string leading up to the first '#'. For instance: * * "ip1,ip2,...#foo=bar" * * For server list requests, the data must begin with a NUL char and be * followed by a byte indicating the version of the data format. Version 1 * looks something like (note this is packed): * * u8 Non-string marker (ie. 0) * u8 Content (DNS_PAYLOAD_IS_*) * u8 Version (e.g. 1) * u8 Source of server list * u8 Lookup status of server list * u8 Number of servers * foreach-server { * __le16 Name length * __le16 Priority (as per SRV record, low first) * __le16 Weight (as per SRV record, higher first) * __le16 Port * u8 Source of address list * u8 Lookup status of address list * u8 Protocol (DNS_SERVER_PROTOCOL_*) * u8 Number of addresses * char[] Name (not NUL-terminated) * foreach-address { * u8 Family (DNS_ADDRESS_IS_*) * union { * u8[4] ipv4_addr * u8[16] ipv6_addr * } * } * } * */ static int dns_resolver_preparse(struct key_preparsed_payload *prep) { struct user_key_payload *upayload; unsigned long derrno; int ret; int datalen = prep->datalen, result_len = 0; const char *data = prep->data, *end, *opt; if (datalen <= 1 || !data) return -EINVAL; if (data[0] == 0) { const struct dns_server_list_v1_header *v1; /* It may be a server list. */ if (datalen < sizeof(*v1)) return -EINVAL; v1 = (const struct dns_server_list_v1_header *)data; kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen); if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) { pr_warn_ratelimited( "dns_resolver: Unsupported content type (%u)\n", v1->hdr.content); return -EINVAL; } if (v1->hdr.version != 1) { pr_warn_ratelimited( "dns_resolver: Unsupported server list version (%u)\n", v1->hdr.version); return -EINVAL; } if ((v1->status != DNS_LOOKUP_GOOD && v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) { if (prep->expiry == TIME64_MAX) prep->expiry = ktime_get_real_seconds() + 1; } result_len = datalen; goto store_result; } kenter("'%*.*s',%u", datalen, datalen, data, datalen); if (!data || data[datalen - 1] != '\0') return -EINVAL; datalen--; /* deal with any options embedded in the data */ end = data + datalen; opt = memchr(data, '#', datalen); if (!opt) { /* no options: the entire data is the result */ kdebug("no options"); result_len = datalen; } else { const char *next_opt; result_len = opt - data; opt++; kdebug("options: '%s'", opt); do { int opt_len, opt_nlen; const char *eq; char optval[128]; next_opt = memchr(opt, '#', end - opt) ?: end; opt_len = next_opt - opt; if (opt_len <= 0 || opt_len > sizeof(optval)) { pr_warn_ratelimited("Invalid option length (%d) for dns_resolver key\n", opt_len); return -EINVAL; } eq = memchr(opt, '=', opt_len); if (eq) { opt_nlen = eq - opt; eq++; memcpy(optval, eq, next_opt - eq); optval[next_opt - eq] = '\0'; } else { opt_nlen = opt_len; optval[0] = '\0'; } kdebug("option '%*.*s' val '%s'", opt_nlen, opt_nlen, opt, optval); /* see if it's an error number representing a DNS error * that's to be recorded as the result in this key */ if (opt_nlen == sizeof(DNS_ERRORNO_OPTION) - 1 && memcmp(opt, DNS_ERRORNO_OPTION, opt_nlen) == 0) { kdebug("dns error number option"); ret = kstrtoul(optval, 10, &derrno); if (ret < 0) goto bad_option_value; if (derrno < 1 || derrno > 511) goto bad_option_value; kdebug("dns error no. = %lu", derrno); prep->payload.data[dns_key_error] = ERR_PTR(-derrno); continue; } bad_option_value: pr_warn_ratelimited("Option '%*.*s' to dns_resolver key: bad/missing value\n", opt_nlen, opt_nlen, opt); return -EINVAL; } while (opt = next_opt + 1, opt < end); } /* don't cache the result if we're caching an error saying there's no * result */ if (prep->payload.data[dns_key_error]) { kleave(" = 0 [h_error %ld]", PTR_ERR(prep->payload.data[dns_key_error])); return 0; } store_result: kdebug("store result"); prep->quotalen = result_len; upayload = kmalloc_flex(*upayload, data, result_len + 1); if (!upayload) { kleave(" = -ENOMEM"); return -ENOMEM; } upayload->datalen = result_len; memcpy(upayload->data, data, result_len); upayload->data[result_len] = '\0'; prep->payload.data[dns_key_data] = upayload; kleave(" = 0"); return 0; } /* * Clean up the preparse data */ static void dns_resolver_free_preparse(struct key_preparsed_payload *prep) { pr_devel("==>%s()\n", __func__); kfree(prep->payload.data[dns_key_data]); } /* * The description is of the form "[<type>:]<domain_name>" * * The domain name may be a simple name or an absolute domain name (which * should end with a period). The domain name is case-independent. */ static bool dns_resolver_cmp(const struct key *key, const struct key_match_data *match_data) { int slen, dlen, ret = 0; const char *src = key->description, *dsp = match_data->raw_data; kenter("%s,%s", src, dsp); if (!src || !dsp) goto no_match; if (strcasecmp(src, dsp) == 0) goto matched; slen = strlen(src); dlen = strlen(dsp); if (slen <= 0 || dlen <= 0) goto no_match; if (src[slen - 1] == '.') slen--; if (dsp[dlen - 1] == '.') dlen--; if (slen != dlen || strncasecmp(src, dsp, slen) != 0) goto no_match; matched: ret = 1; no_match: kleave(" = %d", ret); return ret; } /* * Preparse the match criterion. */ static int dns_resolver_match_preparse(struct key_match_data *match_data) { match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE; match_data->cmp = dns_resolver_cmp; return 0; } /* * Describe a DNS key */ static void dns_resolver_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); if (key_is_positive(key)) { int err = PTR_ERR(key->payload.data[dns_key_error]); if (err) seq_printf(m, ": %d", err); else seq_printf(m, ": %u", key->datalen); } } /* * read the DNS data * - the key's semaphore is read-locked */ static long dns_resolver_read(const struct key *key, char *buffer, size_t buflen) { int err = PTR_ERR(key->payload.data[dns_key_error]); if (err) return err; return user_read(key, buffer, buflen); } struct key_type key_type_dns_resolver = { .name = "dns_resolver", .flags = KEY_TYPE_NET_DOMAIN | KEY_TYPE_INSTANT_REAP, .preparse = dns_resolver_preparse, .free_preparse = dns_resolver_free_preparse, .instantiate = generic_key_instantiate, .match_preparse = dns_resolver_match_preparse, .revoke = user_revoke, .destroy = user_destroy, .describe = dns_resolver_describe, .read = dns_resolver_read, }; static int __init init_dns_resolver(void) { struct cred *cred; struct key *keyring; int ret; /* create an override credential set with a special thread keyring in * which DNS requests are cached * * this is used to prevent malicious redirections from being installed * with add_key(). */ cred = prepare_kernel_cred(&init_task); if (!cred) return -ENOMEM; keyring = keyring_alloc(".dns_resolver", GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred, (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ, KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); if (IS_ERR(keyring)) { ret = PTR_ERR(keyring); goto failed_put_cred; } ret = register_key_type(&key_type_dns_resolver); if (ret < 0) goto failed_put_key; /* instruct request_key() to use this special keyring as a cache for * the results it looks up */ set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags); cred->thread_keyring = keyring; cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; dns_resolver_cache = cred; kdebug("DNS resolver keyring: %d\n", key_serial(keyring)); return 0; failed_put_key: key_put(keyring); failed_put_cred: put_cred(cred); return ret; } static void __exit exit_dns_resolver(void) { key_revoke(dns_resolver_cache->thread_keyring); unregister_key_type(&key_type_dns_resolver); put_cred(dns_resolver_cache); } module_init(init_dns_resolver) module_exit(exit_dns_resolver) MODULE_LICENSE("GPL");