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glibc/SOURCES/glibc-upstream-2.34-320.patch

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commit c288e032ae107c48679ef3c46fb84af6de0a6baf
Author: Florian Weimer <fweimer@redhat.com>
Date: Tue Aug 30 10:02:49 2022 +0200
resolv: Add internal __ns_name_length_uncompressed function
This function is useful for checking that the question name is
uncompressed (as it should be).
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 78b1a4f0e49064e5dfb686c7cd87bd4df2640b29)
diff --git a/include/arpa/nameser.h b/include/arpa/nameser.h
index bb1dede187cf1500..6e4808f00d60caf9 100644
--- a/include/arpa/nameser.h
+++ b/include/arpa/nameser.h
@@ -95,5 +95,13 @@ libc_hidden_proto (__ns_name_unpack)
extern __typeof (ns_samename) __libc_ns_samename;
libc_hidden_proto (__libc_ns_samename)
+/* Packet parser helper functions. */
+
+/* Verify that P points to an uncompressed domain name in wire format.
+ On success, return the length of the encoded name, including the
+ terminating null byte. On failure, return -1 and set errno. EOM
+ must point one past the last byte in the packet. */
+int __ns_name_length_uncompressed (const unsigned char *p,
+ const unsigned char *eom) attribute_hidden;
# endif /* !_ISOMAC */
#endif
diff --git a/resolv/Makefile b/resolv/Makefile
index 0b4fa30716af3b8a..308f18622a04965a 100644
--- a/resolv/Makefile
+++ b/resolv/Makefile
@@ -40,6 +40,7 @@ routines := \
inet_pton \
ns_makecanon \
ns_name_compress \
+ ns_name_length_uncompressed \
ns_name_ntop \
ns_name_pack \
ns_name_pton \
@@ -112,6 +113,10 @@ tests-static += tst-resolv-txnid-collision
tests-internal += tst-ns_samebinaryname
tests-static += tst-ns_samebinaryname
+# Likewise for __ns_name_length_uncompressed.
+tests-internal += tst-ns_name_length_uncompressed
+tests-static += tst-ns_name_length_uncompressed
+
# These tests need libdl.
ifeq (yes,$(build-shared))
tests += \
diff --git a/resolv/ns_name_length_uncompressed.c b/resolv/ns_name_length_uncompressed.c
new file mode 100644
index 0000000000000000..51296b47efbf1849
--- /dev/null
+++ b/resolv/ns_name_length_uncompressed.c
@@ -0,0 +1,72 @@
+/* Skip over an uncompressed name in wire format.
+ Copyright (C) 2022 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <arpa/nameser.h>
+#include <errno.h>
+#include <stdbool.h>
+
+int
+__ns_name_length_uncompressed (const unsigned char *p,
+ const unsigned char *eom)
+{
+ const unsigned char *start = p;
+
+ while (true)
+ {
+ if (p == eom)
+ {
+ /* Truncated packet: no room for label length. */
+ __set_errno (EMSGSIZE);
+ return -1;
+ }
+
+ unsigned char b = *p;
+ ++p;
+ if (b == 0)
+ {
+ /* Root label. */
+ size_t length = p - start;
+ if (length > NS_MAXCDNAME)
+ {
+ /* Domain name too long. */
+ __set_errno (EMSGSIZE);
+ return -1;
+ }
+ return length;
+ }
+
+ if (b <= 63)
+ {
+ /* Regular label. */
+ if (b <= eom - p)
+ p += b;
+ else
+ {
+ /* Truncated packet: label incomplete. */
+ __set_errno (EMSGSIZE);
+ return -1;
+ }
+ }
+ else
+ {
+ /* Compression reference or corrupted label length. */
+ __set_errno (EMSGSIZE);
+ return -1;
+ }
+ }
+}
diff --git a/resolv/tst-ns_name_length_uncompressed.c b/resolv/tst-ns_name_length_uncompressed.c
new file mode 100644
index 0000000000000000..c4a2904db75d1221
--- /dev/null
+++ b/resolv/tst-ns_name_length_uncompressed.c
@@ -0,0 +1,135 @@
+/* Test __ns_name_length_uncompressed.
+ Copyright (C) 2022 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <arpa/nameser.h>
+#include <array_length.h>
+#include <errno.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/next_to_fault.h>
+
+/* Reference implementation based on other building blocks. */
+static int
+reference_length (const unsigned char *p, const unsigned char *eom)
+{
+ unsigned char buf[NS_MAXCDNAME];
+ int n = __ns_name_unpack (p, eom, p, buf, sizeof (buf));
+ if (n < 0)
+ return n;
+ const unsigned char *q = buf;
+ if (__ns_name_skip (&q, array_end (buf)) < 0)
+ return -1;
+ if (q - buf != n)
+ /* Compressed name. */
+ return -1;
+ return n;
+}
+
+static int
+do_test (void)
+{
+ {
+ unsigned char buf[] = { 3, 'w', 'w', 'w', 0, 0, 0 };
+ TEST_COMPARE (reference_length (buf, array_end (buf)), sizeof (buf) - 2);
+ TEST_COMPARE (__ns_name_length_uncompressed (buf, array_end (buf)),
+ sizeof (buf) - 2);
+ TEST_COMPARE (reference_length (array_end (buf) - 1, array_end (buf)), 1);
+ TEST_COMPARE (__ns_name_length_uncompressed (array_end (buf) - 1,
+ array_end (buf)), 1);
+ buf[4] = 0xc0; /* Forward compression reference. */
+ buf[5] = 0x06;
+ TEST_COMPARE (reference_length (buf, array_end (buf)), -1);
+ TEST_COMPARE (__ns_name_length_uncompressed (buf, array_end (buf)), -1);
+ }
+
+ struct support_next_to_fault ntf = support_next_to_fault_allocate (300);
+
+ /* Buffer region with all possible bytes at start and end. */
+ for (int length = 1; length <= 300; ++length)
+ {
+ unsigned char *end = (unsigned char *) ntf.buffer + ntf.length;
+ unsigned char *start = end - length;
+ memset (start, 'X', length);
+ for (int first = 0; first <= 255; ++first)
+ {
+ *start = first;
+ for (int last = 0; last <= 255; ++last)
+ {
+ start[length - 1] = last;
+ TEST_COMPARE (reference_length (start, end),
+ __ns_name_length_uncompressed (start, end));
+ }
+ }
+ }
+
+ /* Poor man's fuzz testing: patch two bytes. */
+ {
+ unsigned char ref[] =
+ {
+ 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'n', 'e', 't', 0, 0, 0
+ };
+ TEST_COMPARE (reference_length (ref, array_end (ref)), 13);
+ TEST_COMPARE (__ns_name_length_uncompressed (ref, array_end (ref)), 13);
+
+ int good = 0;
+ int bad = 0;
+ for (int length = 1; length <= sizeof (ref); ++length)
+ {
+ unsigned char *end = (unsigned char *) ntf.buffer + ntf.length;
+ unsigned char *start = end - length;
+ memcpy (start, ref, length);
+
+ for (int patch1_pos = 0; patch1_pos < length; ++patch1_pos)
+ {
+ for (int patch1_value = 0; patch1_value <= 255; ++patch1_value)
+ {
+ start[patch1_pos] = patch1_value;
+ for (int patch2_pos = 0; patch2_pos < length; ++patch2_pos)
+ {
+ for (int patch2_value = 0; patch2_value <= 255;
+ ++patch2_value)
+ {
+ start[patch2_pos] = patch2_value;
+ int expected = reference_length (start, end);
+ errno = EINVAL;
+ int actual
+ = __ns_name_length_uncompressed (start, end);
+ if (actual > 0)
+ ++good;
+ else
+ {
+ TEST_COMPARE (errno, EMSGSIZE);
+ ++bad;
+ }
+ TEST_COMPARE (expected, actual);
+ }
+ start[patch2_pos] = ref[patch2_pos];
+ }
+ }
+ start[patch1_pos] = ref[patch1_pos];
+ }
+ }
+ printf ("info: patched inputs with success: %d\n", good);
+ printf ("info: patched inputs with failure: %d\n", bad);
+ }
+
+ support_next_to_fault_free (&ntf);
+ return 0;
+}
+
+#include <support/test-driver.c>