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glibc/glibc-rh168253-nss_dns-dead-code.patch
Florian Weimer 8597553f96 Rebase DNS stub resolver to the glibc 2.26 version 
- Support an arbitrary number of search domains (#168253)
- Detect and apply /etc/resolv.conf changes in libresolv (#1374239)
- CVE-2015-5180: DNS stub resolver crash with crafted record type (#1251403)
2017-10-11 14:41:27 +02:00

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commit 3005466abe8fb80ad4ff51865f1e28dd81c43347
Author: Florian Weimer <fweimer@redhat.com>
Date: Wed Sep 6 15:11:44 2017 +0200
nss_dns: Remove dead PTR IPv4-to-IPv6 mapping code
(cherry picked from commit c77eb96925b719001237ca7c9e3cef40d795d66b)
diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index 7cd54ab5048dcd37..1e85e4f08ffc8600 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 1522d5c5f5e4d860..d819f921d6e6746d 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
<http://www.gnu.org/licenses/>. */
+#include <ctype.h>
#include <netdb.h>
#include <resolv.h>
+#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/check_nss.h>
#include <support/resolv_test.h>
+#include <support/support.h>
#include <support/xthread.h>
+/* 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 ();
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