From 3005466abe8fb80ad4ff51865f1e28dd81c43347 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Wed, 6 Sep 2017 15:11:44 +0200 Subject: [PATCH 29] nss_dns: Remove dead PTR IPv4-to-IPv6 mapping code (cherry picked from commit c77eb96925b719001237ca7c9e3cef40d795d66b) --- ChangeLog | 12 +++ resolv/nss_dns/dns-host.c | 13 ---- resolv/tst-res_use_inet6.c | 181 +++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 186 insertions(+), 20 deletions(-) diff --git a/ChangeLog b/ChangeLog index dd71f6c427..fa215c2729 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,17 @@ 2017-09-06 Florian Weimer + Remove dead PTR IPv4-to-IPv6 mapping code from nss_dns. + * resolv/nss_dns/dns-host.c (getanswer_r): Remove dead code. + * resolv/tst-res_use_inet6.c (response_ptr_v4, response_ptr_v6): + New functions. + (response): Call them. Add 'p', '6' flag processing. + (test_reverse): New function. + (test_get2_any): Call it. + (test_no_inet6): Add 'p' test. + (test_inet6): Likewise. + +2017-09-06 Florian Weimer + Enhance tst-res_use_inet6 to test IPv4-to-IPv6 address mapping. * resolv/tst-res_use_inet6.c (response): Process flags embedded in the QNAME. diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c index 7cd54ab504..1e85e4f08f 100644 --- a/resolv/nss_dns/dns-host.c +++ b/resolv/nss_dns/dns-host.c @@ -889,19 +889,6 @@ getanswer_r (struct resolv_context *ctx, /* bind would put multiple PTR records as aliases, but we don't do that. */ result->h_name = bp; - if (have_to_map) - { - n = strlen (bp) + 1; /* for the \0 */ - if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) - { - ++had_error; - break; - } - bp += n; - linebuflen -= n; - if (map_v4v6_hostent (result, &bp, &linebuflen)) - goto too_small; - } *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; case T_A: diff --git a/resolv/tst-res_use_inet6.c b/resolv/tst-res_use_inet6.c index 1522d5c5f5..d819f921d6 100644 --- a/resolv/tst-res_use_inet6.c +++ b/resolv/tst-res_use_inet6.c @@ -16,31 +16,101 @@ License along with the GNU C Library; if not, see . */ +#include #include #include +#include +#include #include #include #include #include +#include #include +/* Handle IPv4 reverse lookup responses. Product a PTR record + A-B-C-D.v4.example. */ +static void +response_ptr_v4 (const struct resolv_response_context *ctx, + struct resolv_response_builder *b, + const char *qname, uint16_t qclass, uint16_t qtype) +{ + int bytes[4]; + int offset = -1; + TEST_VERIFY (sscanf (qname, "%d.%d.%d.%d.in-addr.arpa%n", + bytes + 0, bytes + 1, bytes + 2, bytes + 3, + &offset) == 4); + TEST_VERIFY (offset == strlen (qname)); + resolv_response_init (b, (struct resolv_response_flags) {}); + resolv_response_add_question (b, qname, qclass, qtype); + resolv_response_section (b, ns_s_an); + resolv_response_open_record (b, qname, qclass, T_PTR, 0); + char *name = xasprintf ("%d-%d-%d-%d.v4.example", + bytes[3], bytes[2], bytes[1], bytes[0]); + resolv_response_add_name (b, name); + free (name); + resolv_response_close_record (b); +} + +/* Handle IPv6 reverse lookup responses. Produce a PTR record + <32 hex digits>.v6.example. */ +static void +response_ptr_v6 (const struct resolv_response_context *ctx, + struct resolv_response_builder *b, + const char *qname, uint16_t qclass, uint16_t qtype) +{ + + TEST_VERIFY_EXIT (strlen (qname) > 64); + + char bytes[33]; + for (int i = 0; i < 64; ++i) + if ((i % 2) == 0) + { + TEST_VERIFY (isxdigit ((unsigned char) qname[i])); + bytes[31 - i / 2] = qname[i]; + } + else + TEST_VERIFY_EXIT (qname[i] == '.'); + bytes[32] = '\0'; + + resolv_response_init (b, (struct resolv_response_flags) {}); + resolv_response_add_question (b, qname, qclass, qtype); + resolv_response_section (b, ns_s_an); + resolv_response_open_record (b, qname, qclass, T_PTR, 0); + char *name = xasprintf ("%s.v6.example", bytes); + resolv_response_add_name (b, name); + free (name); + resolv_response_close_record (b); +} + /* Produce a response based on QNAME: Certain characters in the first label of QNAME trigger the inclusion of resource records: 'a' A record (IPv4 address) 'q' AAAA record (quad A record, IPv6 address) + 'p' PTR record 'm' record type must match QTYPE (no additional records) + '6' stop flag processing if QTYPE == AAAA + + For 'a' and 'q', QTYPE is ignored for record type selection if 'm' + is not specified. - QTYPE is ignored for record type selection if 'm' is not - specified. */ + in-addr.arpa and ip6.arpa queries are handled separately in + response_ptr_v4 and response_ptr_v6. */ static void response (const struct resolv_response_context *ctx, struct resolv_response_builder *b, const char *qname, uint16_t qclass, uint16_t qtype) { + if (strstr (qname, ".in-addr.arpa") != NULL) + return response_ptr_v4 (ctx, b, qname, qclass, qtype); + else if (strstr (qname, ".ip6.arpa") != NULL) + return response_ptr_v6 (ctx, b, qname, qclass, qtype); + bool include_a = false; bool include_aaaa = false; bool include_match = false; + bool include_ptr = false; for (const char *p = qname; *p != '.' && *p != '\0'; ++p) { if (*p == 'a') @@ -49,6 +119,10 @@ response (const struct resolv_response_context *ctx, include_aaaa = true; else if (*p == 'm') include_match = true; + else if (*p == 'p') + include_ptr = true; + else if (*p == '6' && qtype == T_AAAA) + break; } if (include_match) { @@ -70,11 +144,17 @@ response (const struct resolv_response_context *ctx, } if (include_aaaa) { - char ipv6[16] - = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; - resolv_response_open_record (b, qname, qclass, T_AAAA, 0); - resolv_response_add_data (b, &ipv6, sizeof (ipv6)); - resolv_response_close_record (b); + char ipv6[16] + = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; + resolv_response_open_record (b, qname, qclass, T_AAAA, 0); + resolv_response_add_data (b, &ipv6, sizeof (ipv6)); + resolv_response_close_record (b); + } + if (include_ptr) + { + resolv_response_open_record (b, qname, qclass, T_PTR, 0); + resolv_response_add_name (b, "ptr-target.example"); + resolv_response_close_record (b); } } @@ -162,6 +242,65 @@ test_gai (void) } } +/* Test gethostbyaddr and getnameinfo. The results are independent of + RES_USE_INET6. */ +static void +test_reverse (void) +{ + { + char ipv4[4] = { 192, 0, 2, 17 }; + check_hostent ("gethostbyaddr AF_INET", + gethostbyaddr (ipv4, sizeof (ipv4), AF_INET), + "name: 192-0-2-17.v4.example\n" + "address: 192.0.2.17\n"); + } + { + char ipv6[16] + = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; + check_hostent ("gethostbyaddr AF_INET", + gethostbyaddr (ipv6, sizeof (ipv6), AF_INET6), + "name: 20010db8000000000000000000000001.v6.example\n" + "address: 2001:db8::1\n"); + } + + { + struct sockaddr_in addr = + { + .sin_family = AF_INET, + .sin_addr = { .s_addr = htonl (0xc0000211) }, + .sin_port = htons (80) + }; + char host[NI_MAXHOST]; + char service[NI_MAXSERV]; + int ret = getnameinfo ((struct sockaddr *) &addr, sizeof (addr), + host, sizeof (host), service, sizeof (service), + NI_NUMERICSERV); + TEST_VERIFY (ret == 0); + TEST_VERIFY (strcmp (host, "192-0-2-17.v4.example") == 0); + TEST_VERIFY (strcmp (service, "80") == 0); + } + { + char ipv6[16] + = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}; + struct sockaddr_in6 addr = + { + .sin6_family = AF_INET6, + .sin6_port = htons (80), + }; + TEST_VERIFY (sizeof (ipv6) == sizeof (addr.sin6_addr)); + memcpy (&addr.sin6_addr, ipv6, sizeof (addr.sin6_addr)); + char host[NI_MAXHOST]; + char service[NI_MAXSERV]; + int ret = getnameinfo ((struct sockaddr *) &addr, sizeof (addr), + host, sizeof (host), service, sizeof (service), + NI_NUMERICSERV); + TEST_VERIFY (ret == 0); + TEST_VERIFY + (strcmp (host, "20010db8000000000000000000000001.v6.example") == 0); + TEST_VERIFY (strcmp (service, "80") == 0); + } +} + /* Test that gethostbyname2 is mostly not influenced by RES_USE_INET6. */ static void @@ -207,6 +346,8 @@ test_get2_any (void) "name: qa.example\n" "address: 2001:db8::1\n"); /* Additional AF_INET6 tests depend on RES_USE_INET6; see below. */ + + test_reverse (); } /* gethostbyname2 tests with RES_USE_INET6 disabled. */ @@ -254,6 +395,10 @@ test_no_inet6 (void) gethostbyname ("am.example"), "name: am.example\n" "address: 192.0.2.17\n"); + check_hostent ("gethostbyname (\"amp.example\")", + gethostbyname ("amp.example"), + "name: amp.example\n" + "address: 192.0.2.17\n"); check_hostent ("gethostbyname (\"qam.example\")", gethostbyname ("qam.example"), "name: qam.example\n" @@ -307,6 +452,28 @@ threadfunc (void *ignored) gethostbyname ("qm.inet6.example"), "name: qm.inet6.example\n" "address: 2001:db8::1\n"); + check_hostent ("gethostbyname (\"amp.inet6.example\")", + gethostbyname ("amp.inet6.example"), + "error: NO_RECOVERY\n"); + check_hostent ("gethostbyname (\"qmp.inet6.example\")", + gethostbyname ("qmp.inet6.example"), + "name: qmp.inet6.example\n" + "address: 2001:db8::1\n"); + check_hostent ("gethostbyname (\"ap.inet6.example\")", + gethostbyname ("ap.inet6.example"), + "error: NO_RECOVERY\n"); + check_hostent ("gethostbyname (\"6ap.inet6.example\")", + gethostbyname ("6ap.inet6.example"), + "name: 6ap.inet6.example\n" + "address: ::ffff:192.0.2.17\n"); + check_hostent ("gethostbyname (\"am6p.inet6.example\")", + gethostbyname ("am6p.inet6.example"), + "name: am6p.inet6.example\n" + "address: ::ffff:192.0.2.17\n"); + check_hostent ("gethostbyname (\"qp.inet6.example\")", + gethostbyname ("qp.inet6.example"), + "name: qp.inet6.example\n" + "address: 2001:db8::1\n"); test_get2_inet6 (); test_get2_inet6 (); test_gai ();