diff options
| -rw-r--r-- | ChangeLog | 19 | ||||
| -rw-r--r-- | resolv/Makefile | 2 | ||||
| -rw-r--r-- | resolv/tst-resolv-binary.c | 120 | ||||
| -rw-r--r-- | support/resolv_test.c | 294 |
4 files changed, 302 insertions, 133 deletions
diff --git a/ChangeLog b/ChangeLog index a7799fcdd6..1fa2eaa6d0 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,24 @@ 2018-01-08 Florian Weimer <fweimer@redhat.com> + resolv: Support binary labels in test framework. + * support/resolv_test.c (struct to_be_freed): Remove. + (struct compressed_name): New. + (allocate_compressed_name, ascii_tolower) + (compare_compressed_name): New functions. + (struct resolv_response_builder): Update type of + compression_offsets for use with tsearch. Rempve to_be_freed. + (response_push_pointer_to_free): Remove function. + (resolv_response_add_name): Rewrite using struct compressed_name + and tsearch instead of hsearch_r. + (response_builder_allocate): Remove initialization of + compression_offsets. + (response_builder_free): Update for removal of to_be_freed. Use + tdestroy instead of hdestroy_r. + * resolv/Makefile (tests): Add tst-resolv-binary. + (tst-resolv-binary): Link with -lresolv -lpthread. + +2018-01-08 Florian Weimer <fweimer@redhat.com> + * support/check.h (TEST_COMPARE): Allow sign mismatch at compile time. Pass positive flag instead of negative flag to support_test_compare_failure. diff --git a/resolv/Makefile b/resolv/Makefile index b98e68f6cc..6e70ae9f6b 100644 --- a/resolv/Makefile +++ b/resolv/Makefile @@ -51,6 +51,7 @@ tests += \ tst-res_hnok \ tst-res_use_inet6 \ tst-resolv-basic \ + tst-resolv-binary \ tst-resolv-edns \ tst-resolv-network \ tst-resolv-res_init-multi \ @@ -159,6 +160,7 @@ $(objpfx)tst-bug18665-tcp: $(objpfx)libresolv.so $(shared-thread-library) $(objpfx)tst-bug18665: $(objpfx)libresolv.so $(shared-thread-library) $(objpfx)tst-res_use_inet6: $(objpfx)libresolv.so $(shared-thread-library) $(objpfx)tst-resolv-basic: $(objpfx)libresolv.so $(shared-thread-library) +$(objpfx)tst-resolv-binary: $(objpfx)libresolv.so $(shared-thread-library) $(objpfx)tst-resolv-edns: $(objpfx)libresolv.so $(shared-thread-library) $(objpfx)tst-resolv-network: $(objpfx)libresolv.so $(shared-thread-library) $(objpfx)tst-resolv-res_init: $(libdl) $(objpfx)libresolv.so diff --git a/resolv/tst-resolv-binary.c b/resolv/tst-resolv-binary.c new file mode 100644 index 0000000000..e7e6d87994 --- /dev/null +++ b/resolv/tst-resolv-binary.c @@ -0,0 +1,120 @@ +/* Test handling of binary domain names with res_send. + Copyright (C) 2018 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 <resolv.h> +#include <string.h> +#include <support/check.h> +#include <support/resolv_test.h> + +static void +response (const struct resolv_response_context *ctx, + struct resolv_response_builder *b, + const char *qname, uint16_t qclass, uint16_t qtype) +{ + TEST_COMPARE (qclass, C_IN); + TEST_COMPARE (qtype, T_TXT); + TEST_VERIFY (strlen (qname) <= 255); + + struct resolv_response_flags flags = { 0 }; + resolv_response_init (b, flags); + resolv_response_add_question (b, qname, qclass, qtype); + resolv_response_section (b, ns_s_an); + resolv_response_open_record (b, qname, qclass, T_TXT, 0x12345678); + unsigned char qnamelen = strlen (qname); + resolv_response_add_data (b, &qnamelen, 1); + resolv_response_add_data (b, qname, qnamelen); + resolv_response_close_record (b); +} + +static int +do_test (void) +{ + struct resolv_test *aux = resolv_test_start + ((struct resolv_redirect_config) + { + .response_callback = response, + }); + + for (int b = 0; b <= 255; ++b) + { + unsigned char query[] = + { + b, b, /* Transaction ID. */ + 1, 0, /* Query with RD flag. */ + 0, 1, /* One question. */ + 0, 0, 0, 0, 0, 0, /* The other sections are empty. */ + 1, b, 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 0, + 0, T_TXT, /* TXT query. */ + 0, 1, /* Class IN. */ + }; + unsigned char response[512]; + int ret = res_send (query, sizeof (query), response, sizeof (response)); + + char expected_name[20]; + /* The name is uncompressed in the query, so we can reference it + directly. */ + TEST_VERIFY_EXIT (ns_name_ntop (query + 12, expected_name, + sizeof (expected_name)) >= 0); + TEST_COMPARE (ret, + (ssize_t) sizeof (query) + + 2 /* Compression reference. */ + + 2 + 2 + 4 + 2 /* Type, class, TTL, RDATA length. */ + + 1 /* Pascal-style string length. */ + + strlen (expected_name)); + + /* Mark as answer, with recursion available, and one answer. */ + query[2] = 0x81; + query[3] = 0x80; + query[7] = 1; + + /* Prefix of the response must match the query. */ + TEST_COMPARE (memcmp (response, query, sizeof (query)), 0); + + /* The actual answer follows, starting with the compression + reference. */ + unsigned char *p = response + sizeof (query); + TEST_COMPARE (*p++, 0xc0); + TEST_COMPARE (*p++, 0x0c); + + /* Type and class. */ + TEST_COMPARE (*p++, 0); + TEST_COMPARE (*p++, T_TXT); + TEST_COMPARE (*p++, 0); + TEST_COMPARE (*p++, C_IN); + + /* TTL. */ + TEST_COMPARE (*p++, 0x12); + TEST_COMPARE (*p++, 0x34); + TEST_COMPARE (*p++, 0x56); + TEST_COMPARE (*p++, 0x78); + + /* RDATA length. */ + TEST_COMPARE (*p++, 0); + TEST_COMPARE (*p++, 1 + strlen (expected_name)); + + /* RDATA. */ + TEST_COMPARE (*p++, strlen (expected_name)); + TEST_COMPARE (memcmp (p, expected_name, strlen (expected_name)), 0); + } + + resolv_test_end (aux); + + return 0; +} + +#include <support/test-driver.c> diff --git a/support/resolv_test.c b/support/resolv_test.c index e968c83633..3f2a09f36f 100644 --- a/support/resolv_test.c +++ b/support/resolv_test.c @@ -43,15 +43,99 @@ enum max_response_length = 65536 }; -/* List of pointers to be freed. The hash table implementation - (struct hsearch_data) does not provide a way to deallocate all - objects, so this approach is used to avoid memory leaks. */ -struct to_be_freed +/* Used for locating domain names containing for the purpose of + forming compression references. */ +struct compressed_name { - struct to_be_freed *next; - void *ptr; + uint16_t offset; + unsigned char length; + unsigned char name[]; /* Without terminating NUL. */ }; +static struct compressed_name * +allocate_compressed_name (const unsigned char *encoded, unsigned int offset) +{ + /* Compute the length of the domain name. */ + size_t length; + { + const unsigned char *p; + for (p = encoded; *p != '\0';) + { + /* No compression references are allowed. */ + TEST_VERIFY (*p <= 63); + /* Skip over the label. */ + p += 1 + *p; + } + length = p - encoded; + ++length; /* For the terminating NUL byte. */ + } + TEST_VERIFY_EXIT (length <= 255); + + struct compressed_name *result + = xmalloc (offsetof (struct compressed_name, name) + length); + result->offset = offset; + result->length = length; + memcpy (result->name, encoded, length); + return result; +} + +/* Convert CH to lower case. Only change letters in the ASCII + range. */ +static inline unsigned char +ascii_tolower (unsigned char ch) +{ + if ('A' <= ch && ch <= 'Z') + return ch - 'A' + 'a'; + else + return ch; +} + +/* Compare both names, for use with tsearch. The order is arbitrary, + but the comparison is case-insenstive. */ +static int +compare_compressed_name (const void *left, const void *right) +{ + const struct compressed_name *crleft = left; + const struct compressed_name *crright = right; + + if (crleft->length != crright->length) + /* The operands are converted to int before the subtraction. */ + return crleft->length - crright->length; + + const unsigned char *nameleft = crleft->name; + const unsigned char *nameright = crright->name; + + while (true) + { + int lenleft = *nameleft++; + int lenright = *nameright++; + + /* Labels must not e compression references. */ + TEST_VERIFY (lenleft <= 63); + TEST_VERIFY (lenright <= 63); + + if (lenleft != lenright) + return left - right; + if (lenleft == 0) + /* End of name reached without spotting a difference. */ + return 0; + /* Compare the label in a case-insenstive manner. */ + const unsigned char *endnameleft = nameleft + lenleft; + while (nameleft < endnameleft) + { + int l = *nameleft++; + int r = *nameright++; + if (l != r) + { + l = ascii_tolower (l); + r = ascii_tolower (r); + if (l != r) + return l - r; + } + } + } +} + struct resolv_response_builder { const unsigned char *query_buffer; @@ -67,11 +151,8 @@ struct resolv_response_builder written RDATA sub-structure. 0 if no RDATA is being written. */ size_t current_rdata_offset; - /* Hash table for locating targets for label compression. */ - struct hsearch_data compression_offsets; - /* List of pointers which need to be freed. Used for domain names - involved in label compression. */ - struct to_be_freed *to_be_freed; + /* tsearch tree for locating targets for label compression. */ + void *compression_offsets; /* Must be last. Not zeroed for performance reasons. */ unsigned char buffer[max_response_length]; @@ -79,18 +160,6 @@ struct resolv_response_builder /* Response builder. */ -/* Add a pointer to the list of pointers to be freed when B is - deallocated. */ -static void -response_push_pointer_to_free (struct resolv_response_builder *b, void *ptr) -{ - if (ptr == NULL) - return; - struct to_be_freed *e = xmalloc (sizeof (*e)); - *e = (struct to_be_freed) {b->to_be_freed, ptr}; - b->to_be_freed = e; -} - void resolv_response_init (struct resolv_response_builder *b, struct resolv_response_flags flags) @@ -194,120 +263,88 @@ void resolv_response_add_name (struct resolv_response_builder *b, const char *const origname) { - /* Normalized name. */ - char *name; - /* Normalized name with case preserved. */ - char *name_case; - { - size_t namelen = strlen (origname); - /* Remove trailing dots. FIXME: Handle trailing quoted dots. */ - while (namelen > 0 && origname[namelen - 1] == '.') - --namelen; - name = xmalloc (namelen + 1); - name_case = xmalloc (namelen + 1); - /* Copy and convert to lowercase. FIXME: This needs to normalize - escaping as well. */ - for (size_t i = 0; i < namelen; ++i) - { - char ch = origname[i]; - name_case[i] = ch; - if ('A' <= ch && ch <= 'Z') - ch = ch - 'A' + 'a'; - name[i] = ch; - } - name[namelen] = 0; - name_case[namelen] = 0; - } - char *name_start = name; - char *name_case_start = name_case; + unsigned char encoded_name[NS_MAXDNAME]; + if (ns_name_pton (origname, encoded_name, sizeof (encoded_name)) < 0) + FAIL_EXIT1 ("ns_name_pton (\"%s\"): %m", origname); - bool compression = false; - while (*name) + /* Copy the encoded name into the output buffer, apply compression + where possible. */ + for (const unsigned char *name = encoded_name; ;) { - /* Search for a previous name we can reference. */ - ENTRY new_entry = + if (*name == '\0') { - .key = name, - .data = (void *) (uintptr_t) b->offset, - }; + /* We have reached the end of the name. Add the terminating + NUL byte. */ + response_add_byte (b, '\0'); + break; + } - /* If the label can be a compression target because it is at a - reachable offset, add it to the hash table. */ - ACTION action; - if (b->offset < (1 << 12)) - action = ENTER; - else - action = FIND; + /* Set to the compression target if compression is possible. */ + struct compressed_name *crname_target; - /* Search for known compression offsets in the hash table. */ - ENTRY *e; - if (hsearch_r (new_entry, action, &e, &b->compression_offsets) == 0) - { - if (action == FIND && errno == ESRCH) - /* Fall through. */ - e = NULL; - else - FAIL_EXIT1 ("hsearch_r failure in name compression: %m"); - } + /* Compression references can only reach the beginning of the + packet. */ + enum { compression_limit = 1 << 12 }; + + { + /* The trailing part of the name to be looked up in the tree + with the compression targets. */ + struct compressed_name *crname + = allocate_compressed_name (name, b->offset); + + if (b->offset < compression_limit) + { + /* Add the name to the tree, for future compression + references. */ + void **ptr = tsearch (crname, &b->compression_offsets, + compare_compressed_name); + if (ptr == NULL) + FAIL_EXIT1 ("tsearch out of memory"); + crname_target = *ptr; + + if (crname_target != crname) + /* The new name was not actually added to the tree. + Deallocate it. */ + free (crname); + else + /* Signal that the tree did not yet contain the name, + but keep the allocation because it is now part of the + tree. */ + crname_target = NULL; + } + else + { + /* This name cannot be reached by a compression reference. + No need to add it to the tree for future reference. */ + void **ptr = tfind (crname, &b->compression_offsets, + compare_compressed_name); + if (ptr != NULL) + crname_target = *ptr; + else + crname_target = NULL; + TEST_VERIFY (crname_target != crname); + /* Not added to the tree. */ + free (crname); + } + } - /* The name is known. Reference the previous location. */ - if (e != NULL && e->data != new_entry.data) + if (crname_target != NULL) { - size_t old_offset = (uintptr_t) e->data; + /* The name is known. Reference the previous location. */ + unsigned int old_offset = crname_target->offset; + TEST_VERIFY_EXIT (old_offset < compression_limit); response_add_byte (b, 0xC0 | (old_offset >> 8)); response_add_byte (b, old_offset); - compression = true; break; } - - /* The name does not exist yet. Write one label. First, add - room for the label length. */ - size_t buffer_label_offset = b->offset; - response_add_byte (b, 0); - - /* Copy the label. */ - while (true) + else { - char ch = *name_case; - if (ch == '\0') - break; - ++name; - ++name_case; - if (ch == '.') - break; - /* FIXME: Handle escaping. */ - response_add_byte (b, ch); + /* The name is new. Add this label. */ + unsigned int len = 1 + *name; + resolv_response_add_data (b, name, len); + name += len; } - - /* Patch in the label length. */ - size_t label_length = b->offset - buffer_label_offset - 1; - if (label_length == 0) - FAIL_EXIT1 ("empty label in name compression: %s", origname); - if (label_length > 63) - FAIL_EXIT1 ("label too long in name compression: %s", origname); - b->buffer[buffer_label_offset] = label_length; - - /* Continue with the tail of the name and the next label. */ - } - - if (compression) - { - /* If we found an immediate match for the name, we have not put - it into the hash table, and can free it immediately. */ - if (name == name_start) - free (name_start); - else - response_push_pointer_to_free (b, name_start); - } - else - { - /* Terminate the sequence of labels. With compression, this is - implicit in the compression reference. */ - response_add_byte (b, 0); - response_push_pointer_to_free (b, name_start); } - - free (name_case_start); } void @@ -403,22 +440,13 @@ response_builder_allocate memset (b, 0, offsetof (struct resolv_response_builder, buffer)); b->query_buffer = query_buffer; b->query_length = query_length; - TEST_VERIFY_EXIT (hcreate_r (10000, &b->compression_offsets) != 0); return b; } static void response_builder_free (struct resolv_response_builder *b) { - struct to_be_freed *current = b->to_be_freed; - while (current != NULL) - { - struct to_be_freed *next = current->next; - free (current->ptr); - free (current); - current = next; - } - hdestroy_r (&b->compression_offsets); + tdestroy (b->compression_offsets, free); free (b); } |