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Tue, 8 Mar 2022 02:07:39 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH 01/12] Simplify allocations and fix merge and continue actions [BZ #28931] Date: Tue, 8 Mar 2022 15:37:06 +0530 Message-Id: <20220308100717.1006126-2-siddhesh@sourceware.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220308100717.1006126-1-siddhesh@sourceware.org> References: <20220308100717.1006126-1-siddhesh@sourceware.org> MIME-Version: 1.0 X-Spam-Status: No, score=-3493.4 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_NONE, KAM_DMARC_STATUS, KAM_SHORT, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NEUTRAL, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Siddhesh Poyarekar via Libc-alpha From: Siddhesh Poyarekar Reply-To: Siddhesh Poyarekar Cc: fweimer@redhat.com Errors-To: libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org Sender: "Libc-alpha" Allocations for address tuples is currently a bit confusing because of the pointer chasing through PAT, making it hard to observe the sequence in which allocations have been made. Narrow scope of the pointer chasing through PAT so that it is only used where necessary. This also tightens actions behaviour with the hosts database in getaddrinfo to comply with the manual text. The "continue" action discards previous results and the "merge" action results in an immedate lookup failure. Consequently, chaining of allocations across modules is no longer necessary, thus opening up cleanup opportunities. A test has been added that checks some combinations to ensure that they work correctly. The "dns [SUCCESS=continue] dns" for example results in a segfault without this fix. Resolves: BZ #28931 Signed-off-by: Siddhesh Poyarekar --- nss/Makefile | 1 + nss/tst-nss-gai-actions.c | 242 ++++++++++++++++++++++++++++++++++++ sysdeps/posix/getaddrinfo.c | 142 +++++++++++++-------- 3 files changed, 333 insertions(+), 52 deletions(-) create mode 100644 nss/tst-nss-gai-actions.c diff --git a/nss/Makefile b/nss/Makefile index 552e5d03e1..43a0b9defe 100644 --- a/nss/Makefile +++ b/nss/Makefile @@ -78,6 +78,7 @@ tests += tst-nss-files-hosts-multi tests += tst-nss-files-hosts-getent tests += tst-nss-files-alias-leak tests += tst-nss-files-alias-truncated +tests += tst-nss-gai-actions endif # If we have a thread library then we can test cancellation against diff --git a/nss/tst-nss-gai-actions.c b/nss/tst-nss-gai-actions.c new file mode 100644 index 0000000000..b5ba5f0138 --- /dev/null +++ b/nss/tst-nss-gai-actions.c @@ -0,0 +1,242 @@ +/* Test continue and merge NSS actions for getaddrinfo. + Copyright The GNU Toolchain Authors. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +enum +{ + ACTION_MERGE = 0, + ACTION_CONTINUE, +}; + +enum +{ + DB_FILES = 0, + DB_DNS, +}; + +struct test_params +{ + int db; + int action; + int family; + bool canon; +}; + +struct support_chroot *chroot_env; + +static void +prepare (int argc, char **argv) +{ + chroot_env = support_chroot_create + ((struct support_chroot_configuration) + { + .resolv_conf = "", + .hosts = "", + .host_conf = "multi on\n", + }); +} + +/* Create the /etc/hosts file from outside the chroot. */ +static void +write_hosts (void) +{ + const int count = 512; + + FILE *fp = xfopen (chroot_env->path_hosts, "w"); + fputs ("127.0.0.1 localhost localhost.localdomain\n" + "::1 localhost localhost.localdomain\n", + fp); + for (int i = 1; i < count; ++i) + fprintf (fp, "192.0.%d.%d gnu.org\n", (i / 256) & 0xff, i & 0xff); + xfclose (fp); +} + +static const char * +family_str (int family) +{ + switch (family) + { + case AF_UNSPEC: + return "AF_UNSPEC"; + case AF_INET: + return "AF_INET"; + default: + __builtin_unreachable (); + } +} + +static const char * +db_str (int db) +{ + switch (db) + { + case DB_DNS: + return "dns"; + case DB_FILES: + return "files"; + default: + __builtin_unreachable (); + } +} + +static const char * +action_str (int action) +{ + switch (action) + { + case ACTION_MERGE: + return "merge"; + case ACTION_CONTINUE: + return "continue"; + default: + __builtin_unreachable (); + } +} + +/* getaddrinfo test. To be run from a subprocess. */ +static void +test_gai (void *closure) +{ + struct test_params *params = closure; + + struct addrinfo hints = + { + .ai_family = params->family, + }; + + struct addrinfo *ai; + + if (params->canon) + hints.ai_flags = AI_CANONNAME; + + /* Use /etc/hosts in the chroot. */ + if (params->db == DB_FILES) + xchroot (chroot_env->path_chroot); + + printf ("***** Testing \"%s [SUCCESS=%s] %s\" for family %s, %s\n", + db_str (params->db), action_str (params->action), + db_str (params->db), family_str (params->family), + params->canon ? "AI_CANONNAME" : ""); + + int ret = getaddrinfo ("gnu.org", "80", &hints, &ai); + + switch (params->action) + { + case ACTION_MERGE: + if (ret == 0) + { + char *formatted = support_format_addrinfo (ai, ret); + + printf ("merge unexpectedly succeeded:\n %s\n", formatted); + support_record_failure (); + free (formatted); + } + else + return; + case ACTION_CONTINUE: + { + char *formatted = support_format_addrinfo (ai, ret); + + if (params->db == DB_FILES) + { + /* Verify that the result appears exactly once. */ + const char *expected = "address: STREAM/TCP 192.0.0.1 80\n" + "address: DGRAM/UDP 192.0.0.1 80\n" + "address: RAW/IP 192.0.0.1 80\n"; + + const char *contains = strstr (formatted, expected); + const char *contains2 = NULL; + + if (contains != NULL) + contains2 = strstr (contains + strlen (expected), expected); + + if (contains == NULL || contains2 != NULL) + { + printf ("continue failed:\n%s\n", formatted); + support_record_failure (); + } + } + else if (ret != 0) + { + printf ("continue unexpectedly failed:\n%s\n", formatted); + support_record_failure (); + } + + free (formatted); + break; + } + default: + __builtin_unreachable (); + } +} + +static void +test_in_subprocess (int db, int action) +{ + char buf[32]; + + snprintf (buf, sizeof (buf), "%s [SUCCESS=%s] %s", + db_str (db), action_str (action), db_str (db)); + __nss_configure_lookup ("hosts", buf); + + struct test_params params = + { + .db = db, + .action = action, + .family = AF_UNSPEC, + .canon = false, + }; + support_isolate_in_subprocess (test_gai, ¶ms); + params.family = AF_INET; + support_isolate_in_subprocess (test_gai, ¶ms); + params.canon = true; + support_isolate_in_subprocess (test_gai, ¶ms); +} + +static int +do_test (void) +{ + support_become_root (); + if (!support_can_chroot ()) + FAIL_UNSUPPORTED ("Cannot chroot\n"); + + write_hosts (); + test_in_subprocess (DB_FILES, ACTION_CONTINUE); + test_in_subprocess (DB_FILES, ACTION_MERGE); + test_in_subprocess (DB_DNS, ACTION_CONTINUE); + test_in_subprocess (DB_DNS, ACTION_MERGE); + + support_chroot_free (chroot_env); + return 0; +} + +#define PREPARE prepare +#include diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c index 18dccd5924..454a27eb2f 100644 --- a/sysdeps/posix/getaddrinfo.c +++ b/sysdeps/posix/getaddrinfo.c @@ -458,11 +458,6 @@ gaih_inet (const char *name, const struct gaih_service *service, if (name != NULL) { - at = alloca_account (sizeof (struct gaih_addrtuple), alloca_used); - at->family = AF_UNSPEC; - at->scopeid = 0; - at->next = NULL; - if (req->ai_flags & AI_IDN) { char *out; @@ -473,13 +468,21 @@ gaih_inet (const char *name, const struct gaih_service *service, malloc_name = true; } - if (__inet_aton_exact (name, (struct in_addr *) at->addr) != 0) + uint32_t addr[4]; + if (__inet_aton_exact (name, (struct in_addr *) addr) != 0) { + at = alloca_account (sizeof (struct gaih_addrtuple), alloca_used); + at->scopeid = 0; + at->next = NULL; + if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET) - at->family = AF_INET; + { + memcpy (at->addr, addr, sizeof (at->addr)); + at->family = AF_INET; + } else if (req->ai_family == AF_INET6 && (req->ai_flags & AI_V4MAPPED)) { - at->addr[3] = at->addr[0]; + at->addr[3] = addr[0]; at->addr[2] = htonl (0xffff); at->addr[1] = 0; at->addr[0] = 0; @@ -493,49 +496,62 @@ gaih_inet (const char *name, const struct gaih_service *service, if (req->ai_flags & AI_CANONNAME) canon = name; + + goto process_list; } - else if (at->family == AF_UNSPEC) + + char *scope_delim = strchr (name, SCOPE_DELIMITER); + int e; + + if (scope_delim == NULL) + e = inet_pton (AF_INET6, name, addr); + else + e = __inet_pton_length (AF_INET6, name, scope_delim - name, addr); + + if (e > 0) { - char *scope_delim = strchr (name, SCOPE_DELIMITER); - int e; - if (scope_delim == NULL) - e = inet_pton (AF_INET6, name, at->addr); + at = alloca_account (sizeof (struct gaih_addrtuple), + alloca_used); + at->scopeid = 0; + at->next = NULL; + + if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6) + { + memcpy (at->addr, addr, sizeof (at->addr)); + at->family = AF_INET6; + } + else if (req->ai_family == AF_INET + && IN6_IS_ADDR_V4MAPPED (addr)) + { + at->addr[0] = addr[3]; + at->addr[1] = addr[1]; + at->addr[2] = addr[2]; + at->addr[3] = addr[3]; + at->family = AF_INET; + } else - e = __inet_pton_length (AF_INET6, name, scope_delim - name, - at->addr); - if (e > 0) { - if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6) - at->family = AF_INET6; - else if (req->ai_family == AF_INET - && IN6_IS_ADDR_V4MAPPED (at->addr)) - { - at->addr[0] = at->addr[3]; - at->family = AF_INET; - } - else - { - result = -EAI_ADDRFAMILY; - goto free_and_return; - } - - if (scope_delim != NULL - && __inet6_scopeid_pton ((struct in6_addr *) at->addr, - scope_delim + 1, - &at->scopeid) != 0) - { - result = -EAI_NONAME; - goto free_and_return; - } + result = -EAI_ADDRFAMILY; + goto free_and_return; + } - if (req->ai_flags & AI_CANONNAME) - canon = name; + if (scope_delim != NULL + && __inet6_scopeid_pton ((struct in6_addr *) at->addr, + scope_delim + 1, + &at->scopeid) != 0) + { + result = -EAI_NONAME; + goto free_and_return; } + + if (req->ai_flags & AI_CANONNAME) + canon = name; + + goto process_list; } - if (at->family == AF_UNSPEC && (req->ai_flags & AI_NUMERICHOST) == 0) + if ((req->ai_flags & AI_NUMERICHOST) == 0) { - struct gaih_addrtuple **pat = &at; int no_data = 0; int no_inet6_data = 0; nss_action_list nip; @@ -543,6 +559,7 @@ gaih_inet (const char *name, const struct gaih_service *service, enum nss_status status = NSS_STATUS_UNAVAIL; int no_more; struct resolv_context *res_ctx = NULL; + bool do_merge = false; /* If we do not have to look for IPv6 addresses or the canonical name, use the simple, old functions, which do not support @@ -579,7 +596,7 @@ gaih_inet (const char *name, const struct gaih_service *service, result = -EAI_MEMORY; goto free_and_return; } - *pat = addrmem; + at = addrmem; } else { @@ -632,6 +649,8 @@ gaih_inet (const char *name, const struct gaih_service *service, } struct gaih_addrtuple *addrfree = addrmem; + struct gaih_addrtuple **pat = &at; + for (int i = 0; i < air->naddrs; ++i) { socklen_t size = (air->family[i] == AF_INET @@ -695,12 +714,6 @@ gaih_inet (const char *name, const struct gaih_service *service, free (air); - if (at->family == AF_UNSPEC) - { - result = -EAI_NONAME; - goto free_and_return; - } - goto process_list; } else if (err == 0) @@ -732,6 +745,21 @@ gaih_inet (const char *name, const struct gaih_service *service, while (!no_more) { + /* Always start afresh; continue should discard previous results + and the hosts database does not support merge. */ + at = NULL; + free (canonbuf); + free (addrmem); + canon = canonbuf = NULL; + addrmem = NULL; + + if (do_merge) + { + __set_h_errno (NETDB_INTERNAL); + __set_errno (EBUSY); + break; + } + no_data = 0; nss_gethostbyname4_r *fct4 = NULL; @@ -744,12 +772,14 @@ gaih_inet (const char *name, const struct gaih_service *service, { while (1) { - status = DL_CALL_FCT (fct4, (name, pat, + status = DL_CALL_FCT (fct4, (name, &at, tmpbuf->data, tmpbuf->length, &errno, &h_errno, NULL)); if (status == NSS_STATUS_SUCCESS) break; + /* gethostbyname4_r may write into AT, so reset it. */ + at = NULL; if (status != NSS_STATUS_TRYAGAIN || errno != ERANGE || h_errno != NETDB_INTERNAL) { @@ -774,7 +804,9 @@ gaih_inet (const char *name, const struct gaih_service *service, no_data = 1; if ((req->ai_flags & AI_CANONNAME) != 0 && canon == NULL) - canon = (*pat)->name; + canon = at->name; + + struct gaih_addrtuple **pat = &at; while (*pat != NULL) { @@ -826,6 +858,8 @@ gaih_inet (const char *name, const struct gaih_service *service, if (fct != NULL) { + struct gaih_addrtuple **pat = &at; + if (req->ai_family == AF_INET6 || req->ai_family == AF_UNSPEC) { @@ -899,6 +933,10 @@ gaih_inet (const char *name, const struct gaih_service *service, if (nss_next_action (nip, status) == NSS_ACTION_RETURN) break; + /* The hosts database does not support MERGE. */ + if (nss_next_action (nip, status) == NSS_ACTION_MERGE) + do_merge = true; + nip++; if (nip->module == NULL) no_more = -1; @@ -930,7 +968,7 @@ gaih_inet (const char *name, const struct gaih_service *service, } process_list: - if (at->family == AF_UNSPEC) + if (at == NULL) { result = -EAI_NONAME; goto free_and_return;