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authorFlorian Weimer <fweimer@redhat.com>2018-07-06 14:23:15 +0200
committerFlorian Weimer <fweimer@redhat.com>2018-07-06 17:52:54 +0200
commit916124ed841745b7a1e0fbc43f9909340b47d373 (patch)
treec523c3829788b33588fdbc1953d889e8fa258ee7 /nss
parent3f5e3f5d066dcffb80af48ae2cf35a01a85a8f10 (diff)
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nss_files: Fix re-reading of long lines [BZ #18991]
Use the new __libc_readline_unlocked function to pick up reading at the same line in case the buffer needs to be enlarged.
Diffstat (limited to 'nss')
-rw-r--r--nss/Makefile2
-rw-r--r--nss/nss_files/files-XXX.c121
-rw-r--r--nss/tst-nss-files-hosts-getent.c276
3 files changed, 328 insertions, 71 deletions
diff --git a/nss/Makefile b/nss/Makefile
index a5cd2aa..66fac7f 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -64,6 +64,7 @@ xtests = bug-erange
ifeq (yes,$(build-shared))
tests += tst-nss-files-hosts-erange
tests += tst-nss-files-hosts-multi
+tests += tst-nss-files-hosts-getent
endif
# If we have a thread library then we can test cancellation against
@@ -169,3 +170,4 @@ endif
$(objpfx)tst-nss-files-hosts-erange: $(libdl)
$(objpfx)tst-nss-files-hosts-multi: $(libdl)
+$(objpfx)tst-nss-files-hosts-getent: $(libdl)
diff --git a/nss/nss_files/files-XXX.c b/nss/nss_files/files-XXX.c
index df33551..60d1544 100644
--- a/nss/nss_files/files-XXX.c
+++ b/nss/nss_files/files-XXX.c
@@ -128,51 +128,6 @@ CONCAT(_nss_files_end,ENTNAME) (void)
}
-typedef enum
-{
- gcr_ok = 0,
- gcr_error = -1,
- gcr_overflow = -2
-} get_contents_ret;
-
-/* Hack around the fact that fgets only accepts int sizes. */
-static get_contents_ret
-get_contents (char *linebuf, size_t len, FILE *stream)
-{
- size_t remaining_len = len;
- char *curbuf = linebuf;
-
- do
- {
- int curlen = ((remaining_len > (size_t) INT_MAX) ? INT_MAX
- : remaining_len);
-
- /* Terminate the line so that we can test for overflow. */
- ((unsigned char *) curbuf)[curlen - 1] = 0xff;
-
- char *p = fgets_unlocked (curbuf, curlen, stream);
-
- /* EOF or read error. */
- if (p == NULL)
- return gcr_error;
-
- /* Done reading in the line. */
- if (((unsigned char *) curbuf)[curlen - 1] == 0xff)
- return gcr_ok;
-
- /* Drop the terminating '\0'. */
- remaining_len -= curlen - 1;
- curbuf += curlen - 1;
- }
- /* fgets copies one less than the input length. Our last iteration is of
- REMAINING_LEN and once that is done, REMAINING_LEN is decremented by
- REMAINING_LEN - 1, leaving the result as 1. */
- while (remaining_len > 1);
-
- /* This means that the current buffer was not large enough. */
- return gcr_overflow;
-}
-
/* Parsing the database file into `struct STRUCTURE' data structures. */
static enum nss_status
internal_getent (FILE *stream, struct STRUCTURE *result,
@@ -191,45 +146,69 @@ internal_getent (FILE *stream, struct STRUCTURE *result,
return NSS_STATUS_TRYAGAIN;
}
- do
+ while (true)
{
- get_contents_ret r = get_contents (data->linebuffer, linebuflen, stream);
-
- if (r == gcr_error)
+ ssize_t r = __libc_readline_unlocked
+ (stream, data->linebuffer, linebuflen);
+ if (r < 0)
+ {
+ *errnop = errno;
+ H_ERRNO_SET (NETDB_INTERNAL);
+ if (*errnop == ERANGE)
+ /* Request larger buffer. */
+ return NSS_STATUS_TRYAGAIN;
+ else
+ /* Other read failure. */
+ return NSS_STATUS_UNAVAIL;
+ }
+ else if (r == 0)
{
- /* End of file or read error. */
+ /* End of file. */
H_ERRNO_SET (HOST_NOT_FOUND);
return NSS_STATUS_NOTFOUND;
}
- if (r == gcr_overflow)
+ /* Everything OK. Now skip leading blanks. */
+ p = data->linebuffer;
+ while (isspace (*p))
+ ++p;
+
+ /* Ignore empty and comment lines. */
+ if (*p == '\0' || *p == '#')
+ continue;
+
+ /* Parse the line. */
+ *errnop = EINVAL;
+ parse_result = parse_line (p, result, data, buflen, errnop EXTRA_ARGS);
+
+ if (parse_result == -1)
{
- /* The line is too long. Give the user the opportunity to
- enlarge the buffer. */
- *errnop = ERANGE;
+ if (*errnop == ERANGE)
+ {
+ /* Return to the original file position at the beginning
+ of the line, so that the next call can read it again
+ if necessary. */
+ if (__fseeko64 (stream, -r, SEEK_CUR) != 0)
+ {
+ if (errno == ERANGE)
+ *errnop = EINVAL;
+ else
+ *errnop = errno;
+ H_ERRNO_SET (NETDB_INTERNAL);
+ return NSS_STATUS_UNAVAIL;
+ }
+ }
H_ERRNO_SET (NETDB_INTERNAL);
return NSS_STATUS_TRYAGAIN;
}
- /* Everything OK. Now skip leading blanks. */
- p = data->linebuffer;
- while (isspace (*p))
- ++p;
- }
- while (*p == '\0' || *p == '#' /* Ignore empty and comment lines. */
- /* Parse the line. If it is invalid, loop to get the next
- line of the file to parse. */
- || ! (parse_result = parse_line (p, result, data, buflen, errnop
- EXTRA_ARGS)));
+ /* Return the data if parsed successfully. */
+ if (parse_result != 0)
+ return NSS_STATUS_SUCCESS;
- if (__glibc_unlikely (parse_result == -1))
- {
- H_ERRNO_SET (NETDB_INTERNAL);
- return NSS_STATUS_TRYAGAIN;
+ /* If it is invalid, loop to get the next line of the file to
+ parse. */
}
-
- /* Filled in RESULT with the next entry from the database file. */
- return NSS_STATUS_SUCCESS;
}
diff --git a/nss/tst-nss-files-hosts-getent.c b/nss/tst-nss-files-hosts-getent.c
new file mode 100644
index 0000000..d7514e8
--- /dev/null
+++ b/nss/tst-nss-files-hosts-getent.c
@@ -0,0 +1,276 @@
+/* Enumerate /etc/hosts with a long line (bug 18991).
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <gnu/lib-names.h>
+#include <netdb.h>
+#include <nss.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/check_nss.h>
+#include <support/namespace.h>
+#include <support/support.h>
+#include <support/test-driver.h>
+#include <support/xmemstream.h>
+#include <support/xstdio.h>
+#include <support/xunistd.h>
+
+struct support_chroot *chroot_env;
+
+/* Number of alias names in the long line. This is varied to catch
+ different cases where the ERANGE handling can go wrong (line buffer
+ length, alias buffer). */
+static int name_count;
+
+/* Write /etc/hosts, from outside of the chroot. */
+static void
+write_hosts (void)
+{
+ FILE *fp = xfopen (chroot_env->path_hosts, "w");
+ fputs ("127.0.0.1 localhost localhost.localdomain\n", fp);
+ fputs ("192.0.2.2 host2.example.com\n", fp);
+ fputs ("192.0.2.1", fp);
+ for (int i = 0; i < name_count; ++i)
+ fprintf (fp, " host%d.example.com", i);
+ fputs ("\n192.0.2.80 www.example.com\n"
+ "192.0.2.5 host5.example.com\n"
+ "192.0.2.81 www1.example.com\n", fp);
+ xfclose (fp);
+}
+
+const char *host1_expected =
+ "name: localhost\n"
+ "alias: localhost.localdomain\n"
+ "address: 127.0.0.1\n";
+const char *host2_expected =
+ "name: host2.example.com\n"
+ "address: 192.0.2.2\n";
+const char *host4_expected =
+ "name: www.example.com\n"
+ "address: 192.0.2.80\n";
+const char *host5_expected =
+ "name: host5.example.com\n"
+ "address: 192.0.2.5\n";
+const char *host6_expected =
+ "name: www1.example.com\n"
+ "address: 192.0.2.81\n";
+
+static void
+prepare (int argc, char **argv)
+{
+ chroot_env = support_chroot_create
+ ((struct support_chroot_configuration)
+ {
+ .resolv_conf = "",
+ .hosts = "", /* Filled in by write_hosts. */
+ .host_conf = "multi on\n",
+ });
+}
+
+/* If -1, no sethostent call. Otherwise, pass do_stayopen as the
+ sethostent argument. */
+static int do_stayopen;
+
+/* If non-zero, perform an endostent call. */
+static int do_endent;
+
+static void
+subprocess_getent (void *closure)
+{
+ xchroot (chroot_env->path_chroot);
+
+ errno = 0;
+ if (do_stayopen >= 0)
+ sethostent (do_stayopen);
+ TEST_VERIFY (errno == 0);
+
+ int i = 0;
+ while (true)
+ {
+ struct xmemstream expected;
+ xopen_memstream (&expected);
+ switch (++i)
+ {
+ case 1:
+ fputs (host1_expected, expected.out);
+ break;
+ case 2:
+ fputs (host2_expected, expected.out);
+ break;
+ case 3:
+ fputs ("name: host0.example.com\n", expected.out);
+ for (int j = 1; j < name_count; ++j)
+ fprintf (expected.out, "alias: host%d.example.com\n", j);
+ fputs ("address: 192.0.2.1\n", expected.out);
+ break;
+ case 4:
+ fputs (host4_expected, expected.out);
+ break;
+ case 5:
+ fputs (host5_expected, expected.out);
+ break;
+ case 6:
+ fputs (host6_expected, expected.out);
+ break;
+ default:
+ fprintf (expected.out, "*** unexpected host %d ***\n", i);
+ break;
+ }
+ xfclose_memstream (&expected);
+ char *context = xasprintf ("do_stayopen=%d host=%d", do_stayopen, i);
+
+ errno = 0;
+ struct hostent *e = gethostent ();
+ if (e == NULL)
+ {
+ TEST_VERIFY (errno == 0);
+ break;
+ }
+ check_hostent (context, e, expected.buffer);
+ free (context);
+ free (expected.buffer);
+ }
+
+ errno = 0;
+ if (do_endent)
+ endhostent ();
+ TEST_VERIFY (errno == 0);
+
+ /* Exercise process termination. */
+ exit (0);
+}
+
+/* getaddrinfo test. To be run from a subprocess. */
+static void
+test_gai (int family)
+{
+ struct addrinfo hints =
+ {
+ .ai_family = family,
+ .ai_protocol = IPPROTO_TCP,
+ .ai_socktype = SOCK_STREAM,
+ };
+
+ struct addrinfo *ai;
+ int ret = getaddrinfo ("host2.example.com", "80", &hints, &ai);
+ check_addrinfo ("host2.example.com", ai, ret,
+ "address: STREAM/TCP 192.0.2.2 80\n"
+ "address: STREAM/TCP 192.0.2.1 80\n");
+
+ ret = getaddrinfo ("host5.example.com", "80", &hints, &ai);
+ check_addrinfo ("host5.example.com", ai, ret,
+ "address: STREAM/TCP 192.0.2.1 80\n"
+ "address: STREAM/TCP 192.0.2.5 80\n");
+
+ ret = getaddrinfo ("www.example.com", "80", &hints, &ai);
+ check_addrinfo ("www.example.com", ai, ret,
+ "address: STREAM/TCP 192.0.2.80 80\n");
+
+ ret = getaddrinfo ("www1.example.com", "80", &hints, &ai);
+ check_addrinfo ("www1.example.com", ai, ret,
+ "address: STREAM/TCP 192.0.2.81 80\n");
+}
+
+/* Subprocess routine for gethostbyname/getaddrinfo testing. */
+static void
+subprocess_gethost (void *closure)
+{
+ xchroot (chroot_env->path_chroot);
+
+ /* This tests enlarging the read buffer in the multi case. */
+ struct xmemstream expected;
+ xopen_memstream (&expected);
+ fputs ("name: host2.example.com\n", expected.out);
+ for (int j = 1; j < name_count; ++j)
+ /* NB: host2 is duplicated in the alias list. */
+ fprintf (expected.out, "alias: host%d.example.com\n", j);
+ fputs ("alias: host0.example.com\n"
+ "address: 192.0.2.2\n"
+ "address: 192.0.2.1\n",
+ expected.out);
+ xfclose_memstream (&expected);
+ check_hostent ("host2.example.com",
+ gethostbyname ("host2.example.com"),
+ expected.buffer);
+ free (expected.buffer);
+
+ /* Similarly, but with a different order in the /etc/hosts file. */
+ xopen_memstream (&expected);
+ fputs ("name: host0.example.com\n", expected.out);
+ for (int j = 1; j < name_count; ++j)
+ fprintf (expected.out, "alias: host%d.example.com\n", j);
+ /* NB: host5 is duplicated in the alias list. */
+ fputs ("alias: host5.example.com\n"
+ "address: 192.0.2.1\n"
+ "address: 192.0.2.5\n",
+ expected.out);
+ xfclose_memstream (&expected);
+ check_hostent ("host5.example.com",
+ gethostbyname ("host5.example.com"),
+ expected.buffer);
+ free (expected.buffer);
+
+ check_hostent ("www.example.com",
+ gethostbyname ("www.example.com"),
+ host4_expected);
+ check_hostent ("www1.example.com",
+ gethostbyname ("www1.example.com"),
+ host6_expected);
+
+ test_gai (AF_INET);
+ test_gai (AF_UNSPEC);
+}
+
+static int
+do_test (void)
+{
+ support_become_root ();
+ if (!support_can_chroot ())
+ return EXIT_UNSUPPORTED;
+
+ __nss_configure_lookup ("hosts", "files");
+ if (dlopen (LIBNSS_FILES_SO, RTLD_LAZY) == NULL)
+ FAIL_EXIT1 ("could not load " LIBNSS_DNS_SO ": %s", dlerror ());
+
+ /* Each name takes about 20 bytes, so this covers a wide range of
+ buffer sizes, from less than 1000 bytes to about 18000 bytes. */
+ for (name_count = 40; name_count <= 850; ++name_count)
+ {
+ write_hosts ();
+
+ for (do_stayopen = -1; do_stayopen < 2; ++do_stayopen)
+ for (do_endent = 0; do_endent < 2; ++do_endent)
+ {
+ if (test_verbose > 0)
+ printf ("info: name_count=%d do_stayopen=%d do_endent=%d\n",
+ name_count, do_stayopen, do_endent);
+ support_isolate_in_subprocess (subprocess_getent, NULL);
+ }
+
+ support_isolate_in_subprocess (subprocess_gethost, NULL);
+ }
+
+ support_chroot_free (chroot_env);
+ return 0;
+}
+
+#define PREPARE prepare
+#include <support/test-driver.c>