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Backport /etc/resolv.conf enhancements to thelp with RHEL-18039 testing

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Related: RHEL-18039
This commit is contained in:
Florian Weimer 2024-07-31 16:02:44 +02:00
parent b30ff9539f
commit 9404e14f4d
3 changed files with 290 additions and 1 deletions
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79
RHEL-18039-1.patch Normal file
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@ -0,0 +1,79 @@
commit 95f61610f3e481d191b6184432342236fd59186d
Author: Florian Weimer <fweimer@redhat.com>
Date: Wed Jul 24 12:06:47 2024 +0200
resolv: Support clearing option flags with a “-” prefix (bug 14799)
I think using a “-” prefix is less confusing than introducing
double-negation construct (“no-no-tld-query”).
Reviewed-by: DJ Delorie <dj@redhat.com>
diff --git a/resolv/res_init.c b/resolv/res_init.c
index 263263d474721545..243532b3ade338d8 100644
--- a/resolv/res_init.c
+++ b/resolv/res_init.c
@@ -682,27 +682,29 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options)
{
char str[22];
uint8_t len;
- uint8_t clear;
unsigned long int flag;
} options[] = {
#define STRnLEN(str) str, sizeof (str) - 1
- { STRnLEN ("rotate"), 0, RES_ROTATE },
- { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
- { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
- { STRnLEN ("single-request"), 0, RES_SNGLKUP },
- { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
- { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
- { STRnLEN ("no-reload"), 0, RES_NORELOAD },
- { STRnLEN ("use-vc"), 0, RES_USEVC },
- { STRnLEN ("trust-ad"), 0, RES_TRUSTAD },
- { STRnLEN ("no-aaaa"), 0, RES_NOAAAA },
+ { STRnLEN ("rotate"), RES_ROTATE },
+ { STRnLEN ("edns0"), RES_USE_EDNS0 },
+ { STRnLEN ("single-request-reopen"), RES_SNGLKUPREOP },
+ { STRnLEN ("single-request"), RES_SNGLKUP },
+ { STRnLEN ("no_tld_query"), RES_NOTLDQUERY },
+ { STRnLEN ("no-tld-query"), RES_NOTLDQUERY },
+ { STRnLEN ("no-reload"), RES_NORELOAD },
+ { STRnLEN ("use-vc"), RES_USEVC },
+ { STRnLEN ("trust-ad"), RES_TRUSTAD },
+ { STRnLEN ("no-aaaa"), RES_NOAAAA },
};
#define noptions (sizeof (options) / sizeof (options[0]))
+ bool negate_option = *cp == '-';
+ if (negate_option)
+ ++cp;
for (int i = 0; i < noptions; ++i)
if (strncmp (cp, options[i].str, options[i].len) == 0)
{
- if (options[i].clear)
- parser->template.options &= options[i].flag;
+ if (negate_option)
+ parser->template.options &= ~options[i].flag;
else
parser->template.options |= options[i].flag;
break;
diff --git a/resolv/tst-resolv-res_init-skeleton.c b/resolv/tst-resolv-res_init-skeleton.c
index 6bef62cde2cbf8cd..d3a19eb305d41467 100644
--- a/resolv/tst-resolv-res_init-skeleton.c
+++ b/resolv/tst-resolv-res_init-skeleton.c
@@ -679,6 +679,16 @@ struct test_case test_cases[] =
"; nameserver[0]: [192.0.2.1]:53\n",
.res_options = "attempts:5 ndots:3 edns0 ",
},
+ {.name = "RES_OPTIONS can clear flags",
+ .conf = "options ndots:2 use-vc no-aaaa edns0\n"
+ "nameserver 192.0.2.1\n",
+ .expected = "options ndots:3 use-vc\n"
+ "search example.com\n"
+ "; search[0]: example.com\n"
+ "nameserver 192.0.2.1\n"
+ "; nameserver[0]: [192.0.2.1]:53\n",
+ .res_options = "ndots:3 -edns0 -no-aaaa",
+ },
{.name = "many search list entries (bug 19569)",
.conf = "nameserver 192.0.2.1\n"
"search corp.example.com support.example.com"

204
RHEL-18039-2.patch Normal file
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@ -0,0 +1,204 @@
commit 765325951ac5c7d072278c9424930b29657e9758
Author: Florian Weimer <fweimer@redhat.com>
Date: Wed Jul 24 12:06:47 2024 +0200
resolv: Implement strict-error stub resolver option (bug 27929)
For now, do not enable this mode by default due to the potential
impact on compatibility with existing deployments.
Reviewed-by: DJ Delorie <dj@redhat.com>
diff --git a/resolv/res_init.c b/resolv/res_init.c
index 243532b3ade338d8..b838dc70642e1935 100644
--- a/resolv/res_init.c
+++ b/resolv/res_init.c
@@ -695,6 +695,7 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options)
{ STRnLEN ("use-vc"), RES_USEVC },
{ STRnLEN ("trust-ad"), RES_TRUSTAD },
{ STRnLEN ("no-aaaa"), RES_NOAAAA },
+ { STRnLEN ("strict-error"), RES_STRICTERR },
};
#define noptions (sizeof (options) / sizeof (options[0]))
bool negate_option = *cp == '-';
diff --git a/resolv/res_send.c b/resolv/res_send.c
index 9c77613f374e5469..9a284ed44aa8cc2e 100644
--- a/resolv/res_send.c
+++ b/resolv/res_send.c
@@ -1234,21 +1234,38 @@ send_dg(res_state statp,
if (thisansp_error) {
next_ns:
- if (recvresp1 || (buf2 != NULL && recvresp2)) {
- *resplen2 = 0;
- return resplen;
- }
- if (buf2 != NULL && !single_request)
+ /* Outside of strict-error mode, use the first
+ response even if the second response is an
+ error. This allows parallel resolution to
+ succeed even if the recursive resolver
+ always answers with SERVFAIL for AAAA
+ queries (which still happens in practice
+ unfortunately).
+
+ In strict-error mode, always switch to the
+ next server and try to get a response from
+ there. */
+ if ((statp->options & RES_STRICTERR) == 0)
{
- /* No data from the first reply. */
- resplen = 0;
- /* We are waiting for a possible second reply. */
- if (matching_query == 1)
- recvresp1 = 1;
- else
- recvresp2 = 1;
-
- goto wait;
+ if (recvresp1 || (buf2 != NULL && recvresp2))
+ {
+ *resplen2 = 0;
+ return resplen;
+ }
+
+ if (buf2 != NULL && !single_request)
+ {
+ /* No data from the first reply. */
+ resplen = 0;
+ /* We are waiting for a possible
+ second reply. */
+ if (matching_query == 1)
+ recvresp1 = 1;
+ else
+ recvresp2 = 1;
+
+ goto wait;
+ }
}
/* don't retry if called from dig */
diff --git a/resolv/resolv.h b/resolv/resolv.h
index f40d6c58cee0f585..b8a0f66a5fd50e22 100644
--- a/resolv/resolv.h
+++ b/resolv/resolv.h
@@ -133,6 +133,7 @@ struct res_sym {
#define RES_NORELOAD 0x02000000 /* No automatic configuration reload. */
#define RES_TRUSTAD 0x04000000 /* Request AD bit, keep it in responses. */
#define RES_NOAAAA 0x08000000 /* Suppress AAAA queries. */
+#define RES_STRICTERR 0x10000000 /* Report more DNS errors as errors. */
#define RES_DEFAULT (RES_RECURSE|RES_DEFNAMES|RES_DNSRCH)
diff --git a/resolv/tst-resolv-res_init-skeleton.c b/resolv/tst-resolv-res_init-skeleton.c
index d3a19eb305d41467..e41bcebd9d9a8024 100644
--- a/resolv/tst-resolv-res_init-skeleton.c
+++ b/resolv/tst-resolv-res_init-skeleton.c
@@ -129,6 +129,7 @@ print_resp (FILE *fp, res_state resp)
print_option_flag (fp, &options, RES_NORELOAD, "no-reload");
print_option_flag (fp, &options, RES_TRUSTAD, "trust-ad");
print_option_flag (fp, &options, RES_NOAAAA, "no-aaaa");
+ print_option_flag (fp, &options, RES_STRICTERR, "strict-error");
fputc ('\n', fp);
if (options != 0)
fprintf (fp, "; error: unresolved option bits: 0x%x\n", options);
@@ -741,6 +742,15 @@ struct test_case test_cases[] =
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
+ {.name = "strict-error flag",
+ .conf = "options strict-error\n"
+ "nameserver 192.0.2.1\n",
+ .expected = "options strict-error\n"
+ "search example.com\n"
+ "; search[0]: example.com\n"
+ "nameserver 192.0.2.1\n"
+ "; nameserver[0]: [192.0.2.1]:53\n"
+ },
{ NULL }
};
diff --git a/resolv/tst-resolv-semi-failure.c b/resolv/tst-resolv-semi-failure.c
index aa9798b5a7dfaa88..b7681210f450bb5a 100644
--- a/resolv/tst-resolv-semi-failure.c
+++ b/resolv/tst-resolv-semi-failure.c
@@ -67,6 +67,9 @@ response (const struct resolv_response_context *ctx,
resolv_response_close_record (b);
}
+/* Set to 1 if strict error checking is enabled. */
+static int do_strict_error;
+
static void
check_one (void)
{
@@ -83,7 +86,10 @@ check_one (void)
struct addrinfo *ai;
int ret = getaddrinfo ("www.example", "80", &hints, &ai);
const char *expected;
- if (ret == 0 && ai->ai_next != NULL)
+ /* In strict-error mode, a switch to the second name server
+ happens, and both responses are received, so a single
+ response is a bug. */
+ if (do_strict_error || (ret == 0 && ai->ai_next != NULL))
expected = ("address: STREAM/TCP 192.0.2.17 80\n"
"address: STREAM/TCP 2001:db8::1 80\n");
else
@@ -99,33 +105,36 @@ check_one (void)
static int
do_test (void)
{
- for (int do_single_lookup = 0; do_single_lookup < 2; ++do_single_lookup)
- {
- struct resolv_test *aux = resolv_test_start
- ((struct resolv_redirect_config)
- {
- .response_callback = response,
- });
+ for (do_strict_error = 0; do_strict_error < 2; ++do_strict_error)
+ for (int do_single_lookup = 0; do_single_lookup < 2; ++do_single_lookup)
+ {
+ struct resolv_test *aux = resolv_test_start
+ ((struct resolv_redirect_config)
+ {
+ .response_callback = response,
+ });
- if (do_single_lookup)
- _res.options |= RES_SNGLKUP;
+ if (do_strict_error)
+ _res.options |= RES_STRICTERR;
+ if (do_single_lookup)
+ _res.options |= RES_SNGLKUP;
- for (int do_fail_aaaa = 0; do_fail_aaaa < 2; ++do_fail_aaaa)
- {
- fail_aaaa = do_fail_aaaa;
+ for (int do_fail_aaaa = 0; do_fail_aaaa < 2; ++do_fail_aaaa)
+ {
+ fail_aaaa = do_fail_aaaa;
- rcode = 2; /* SERVFAIL. */
- check_one ();
+ rcode = 2; /* SERVFAIL. */
+ check_one ();
- rcode = 4; /* NOTIMP. */
- check_one ();
+ rcode = 4; /* NOTIMP. */
+ check_one ();
- rcode = 5; /* REFUSED. */
- check_one ();
- }
+ rcode = 5; /* REFUSED. */
+ check_one ();
+ }
- resolv_test_end (aux);
- }
+ resolv_test_end (aux);
+ }
return 0;
}

8
glibc.spec
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@ -170,7 +170,7 @@ Version: %{glibcversion}
# - It allows using the Release number without the %%dist tag in the dependency
# generator to make the generated requires interchangeable between Rawhide
# and ELN (.elnYY < .fcXX).
%global baserelease 21
%global baserelease 22
Release: %{baserelease}%{?dist}
# Licenses:
@ -429,6 +429,8 @@ Patch116: glibc-upstream-2.39-91.patch
Patch117: glibc-upstream-2.39-92.patch
Patch118: glibc-upstream-2.39-93.patch
Patch119: glibc-upstream-2.39-94.patch
Patch120: RHEL-18039-1.patch
Patch121: RHEL-18039-2.patch
##############################################################################
# Continued list of core "glibc" package information:
@ -2659,6 +2661,10 @@ update_gconv_modules_cache ()
%endif
%changelog
* Wed Jul 31 2024 Florian Weimer <fweimer@redhat.com> - 2.39-22
- Support clearing options in /etc/resolv.conf, RES_OPTIONS with a - prefix
- Introduce the strict-error/RES_STRICTERR stub resolver option (RHEL-18039)
* Wed Jul 31 2024 Arjun Shankar <arjun@redhat.com> - 2.39-21
- Sync with upstream branch release/2.39/master,
commit 4bdcc1963bc2b5ba5f8e319e402d9eb2cb6096c1: