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-rw-r--r--src/util/ip_match.c676
1 files changed, 676 insertions, 0 deletions
diff --git a/src/util/ip_match.c b/src/util/ip_match.c
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+++ b/src/util/ip_match.c
@@ -0,0 +1,676 @@
+/*++
+/* NAME
+/* ip_match 3
+/* SUMMARY
+/* IP address pattern matching
+/* SYNOPSIS
+/* #include <ip_match.h>
+/*
+/* char *ip_match_parse(byte_codes, pattern)
+/* VSTRING *byte_codes;
+/* char *pattern;
+/*
+/* char *ip_match_save(byte_codes)
+/* const VSTRING *byte_codes;
+/*
+/* int ip_match_execute(byte_codes, addr_bytes)
+/* cost char *byte_codes;
+/* const char *addr_bytes;
+/*
+/* char *ip_match_dump(printable, byte_codes)
+/* VSTRING *printable;
+/* const char *byte_codes;
+/* DESCRIPTION
+/* This module supports IP address pattern matching. See below
+/* for a description of the supported address pattern syntax.
+/*
+/* This implementation aims to minimize the cost of encoding
+/* the pattern in internal form, while still providing good
+/* matching performance in the typical case. The first byte
+/* of an encoded pattern specifies the expected address family
+/* (for example, AF_INET); other details of the encoding are
+/* private and are subject to change.
+/*
+/* ip_match_parse() converts the user-specified pattern to
+/* internal form. The result value is a null pointer in case
+/* of success, or a pointer into the byte_codes buffer with a
+/* detailed problem description.
+/*
+/* ip_match_save() saves the result from ip_match_parse() for
+/* longer-term usage. The result should be passed to myfree().
+/*
+/* ip_match_execute() matches a binary network in addr_bytes
+/* against a byte-code array in byte_codes. It is an error to
+/* use different address families for the byte_codes and addr_bytes
+/* arguments (the first byte-code value contains the expected
+/* address family). The result is non-zero in case of success.
+/*
+/* ip_match_dump() produces an ASCII dump of a byte-code array.
+/* The dump is supposed to be identical to the input pattern
+/* modulo upper/lower case or leading nulls with IPv6). This
+/* function is primarily a debugging aid.
+/*
+/* Arguments
+/* .IP addr_bytes
+/* Binary network address in network-byte order.
+/* .IP byte_codes
+/* Byte-code array produced by ip_match_parse().
+/* .IP pattern
+/* Human-readable address pattern.
+/* .IP printable
+/* storage for ASCII dump of a byte-code array.
+/* IPV4 PATTERN SYNTAX
+/* .ad
+/* .fi
+/* An IPv4 address pattern has four fields separated by ".".
+/* Each field is either a decimal number, or a sequence inside
+/* "[]" that contains one or more ";"-separated decimal
+/* numbers or number..number ranges.
+/*
+/* Examples of patterns are 1.2.3.4 (matches itself, as one
+/* would expect) and 1.2.3.[2,4,6..8] (matches 1.2.3.2, 1.2.3.4,
+/* 1.2.3.6, 1.2.3.7, 1.2.3.8).
+/*
+/* Thus, any pattern field can be a sequence inside "[]", but
+/* a "[]" sequence cannot span multiple address fields, and
+/* a pattern field cannot contain both a number and a "[]"
+/* sequence at the same time.
+/*
+/* This means that the pattern 1.2.[3.4] is not valid (the
+/* sequence [3.4] cannot span two address fields) and the
+/* pattern 1.2.3.3[6..9] is also not valid (the last field
+/* cannot be both number 3 and sequence [6..9] at the same
+/* time).
+/*
+/* The syntax for IPv4 patterns is as follows:
+/*
+/* .in +5
+/* v4pattern = v4field "." v4field "." v4field "." v4field
+/* .br
+/* v4field = v4octet | "[" v4sequence "]"
+/* .br
+/* v4octet = any decimal number in the range 0 through 255
+/* .br
+/* v4sequence = v4seq_member | v4sequence ";" v4seq_member
+/* .br
+/* v4seq_member = v4octet | v4octet ".." v4octet
+/* .in
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this
+/* software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <sys/socket.h>
+#include <ctype.h>
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <vstring.h>
+#include <ip_match.h>
+
+ /*
+ * Token values. The in-band values are also used as byte-code values.
+ */
+#define IP_MATCH_CODE_OPEN '[' /* in-band */
+#define IP_MATCH_CODE_CLOSE ']' /* in-band */
+#define IP_MATCH_CODE_OVAL 'N' /* in-band */
+#define IP_MATCH_CODE_RANGE 'R' /* in-band */
+#define IP_MATCH_CODE_EOF '\0' /* in-band */
+#define IP_MATCH_CODE_ERR 256 /* out-of-band */
+
+ /*
+ * SLMs.
+ */
+#define STR vstring_str
+#define LEN VSTRING_LEN
+
+/* ip_match_save - make longer-term copy of byte code */
+
+char *ip_match_save(const VSTRING *byte_codes)
+{
+ char *dst;
+
+ dst = mymalloc(LEN(byte_codes));
+ return (memcpy(dst, STR(byte_codes), LEN(byte_codes)));
+}
+
+/* ip_match_dump - byte-code pretty printer */
+
+char *ip_match_dump(VSTRING *printable, const char *byte_codes)
+{
+ const char *myname = "ip_match_dump";
+ const unsigned char *bp;
+ int octet_count = 0;
+ int ch;
+
+ /*
+ * Sanity check. Use different dumping loops for AF_INET and AF_INET6.
+ */
+ if (*byte_codes != AF_INET)
+ msg_panic("%s: malformed byte-code header", myname);
+
+ /*
+ * Pretty-print and sanity-check the byte codes. Note: the loops in this
+ * code have no auto-increment at the end of the iteration. Instead, each
+ * byte-code handler bumps the byte-code pointer appropriately.
+ */
+ VSTRING_RESET(printable);
+ bp = (const unsigned char *) byte_codes + 1;
+ for (;;) {
+
+ /*
+ * Simple numeric field.
+ */
+ if ((ch = *bp++) == IP_MATCH_CODE_OVAL) {
+ vstring_sprintf_append(printable, "%d", *bp);
+ bp += 1;
+ }
+
+ /*
+ * Wild-card numeric field.
+ */
+ else if (ch == IP_MATCH_CODE_OPEN) {
+ vstring_sprintf_append(printable, "[");
+ for (;;) {
+ /* Numeric range. */
+ if ((ch = *bp++) == IP_MATCH_CODE_RANGE) {
+ vstring_sprintf_append(printable, "%d..%d", bp[0], bp[1]);
+ bp += 2;
+ }
+ /* Number. */
+ else if (ch == IP_MATCH_CODE_OVAL) {
+ vstring_sprintf_append(printable, "%d", *bp);
+ bp += 1;
+ }
+ /* End-of-wildcard. */
+ else if (ch == IP_MATCH_CODE_CLOSE) {
+ break;
+ }
+ /* Corruption. */
+ else {
+ msg_panic("%s: unexpected byte code (decimal %d) "
+ "after \"%s\"", myname, ch, STR(printable));
+ }
+ /* Output the wild-card field separator and repeat the loop. */
+ if (*bp != IP_MATCH_CODE_CLOSE)
+ vstring_sprintf_append(printable, ";");
+ }
+ vstring_sprintf_append(printable, "]");
+ }
+
+ /*
+ * Corruption.
+ */
+ else {
+ msg_panic("%s: unexpected byte code (decimal %d) after \"%s\"",
+ myname, ch, STR(printable));
+ }
+
+ /*
+ * Require four octets, not one more, not one less.
+ */
+ if (++octet_count == 4) {
+ if (*bp != 0)
+ msg_panic("%s: unexpected byte code (decimal %d) after \"%s\"",
+ myname, ch, STR(printable));
+ return (STR(printable));
+ }
+ if (*bp == 0)
+ msg_panic("%s: truncated byte code after \"%s\"",
+ myname, STR(printable));
+
+ /*
+ * Output the address field separator and repeat the loop.
+ */
+ vstring_sprintf_append(printable, ".");
+ }
+}
+
+/* ip_match_print_code_prefix - printable byte-code prefix */
+
+static char *ip_match_print_code_prefix(const char *byte_codes, size_t len)
+{
+ static VSTRING *printable = 0;
+ const char *fmt;
+ const char *bp;
+
+ /*
+ * This is primarily for emergency debugging so we don't care about
+ * non-reentrancy.
+ */
+ if (printable == 0)
+ printable = vstring_alloc(100);
+ else
+ VSTRING_RESET(printable);
+
+ /*
+ * Use decimal for IPv4 and hexadecimal otherwise, so that address octet
+ * values are easy to recognize.
+ */
+ fmt = (*byte_codes == AF_INET ? "%d " : "%02x ");
+ for (bp = byte_codes; bp < byte_codes + len; bp++)
+ vstring_sprintf_append(printable, fmt, *(const unsigned char *) bp);
+
+ return (STR(printable));
+}
+
+/* ip_match_execute - byte-code matching engine */
+
+int ip_match_execute(const char *byte_codes, const char *addr_bytes)
+{
+ const char *myname = "ip_match_execute";
+ const unsigned char *bp;
+ const unsigned char *ap;
+ int octet_count = 0;
+ int ch;
+ int matched;
+
+ /*
+ * Sanity check. Use different execute loops for AF_INET and AF_INET6.
+ */
+ if (*byte_codes != AF_INET)
+ msg_panic("%s: malformed byte-code header (decimal %d)",
+ myname, *(const unsigned char *) byte_codes);
+
+ /*
+ * Match the address bytes against the byte codes. Avoid problems with
+ * (char -> int) sign extension on architectures with signed characters.
+ */
+ bp = (const unsigned char *) byte_codes + 1;
+ ap = (const unsigned char *) addr_bytes;
+
+ for (octet_count = 0; octet_count < 4; octet_count++, ap++) {
+
+ /*
+ * Simple numeric field.
+ */
+ if ((ch = *bp++) == IP_MATCH_CODE_OVAL) {
+ if (*ap == *bp)
+ bp += 1;
+ else
+ return (0);
+ }
+
+ /*
+ * Wild-card numeric field.
+ */
+ else if (ch == IP_MATCH_CODE_OPEN) {
+ matched = 0;
+ for (;;) {
+ /* Numeric range. */
+ if ((ch = *bp++) == IP_MATCH_CODE_RANGE) {
+ if (!matched)
+ matched = (*ap >= bp[0] && *ap <= bp[1]);
+ bp += 2;
+ }
+ /* Number. */
+ else if (ch == IP_MATCH_CODE_OVAL) {
+ if (!matched)
+ matched = (*ap == *bp);
+ bp += 1;
+ }
+ /* End-of-wildcard. */
+ else if (ch == IP_MATCH_CODE_CLOSE) {
+ break;
+ }
+ /* Corruption. */
+ else {
+ size_t len = (const char *) bp - byte_codes - 1;
+
+ msg_panic("%s: unexpected byte code (decimal %d) "
+ "after \"%s\"", myname, ch,
+ ip_match_print_code_prefix(byte_codes, len));
+ }
+ }
+ if (matched == 0)
+ return (0);
+ }
+
+ /*
+ * Corruption.
+ */
+ else {
+ size_t len = (const char *) bp - byte_codes - 1;
+
+ msg_panic("%s: unexpected byte code (decimal %d) after \"%s\"",
+ myname, ch, ip_match_print_code_prefix(byte_codes, len));
+ }
+ }
+ return (1);
+}
+
+/* ip_match_next_token - carve out the next token from input pattern */
+
+static int ip_match_next_token(char **pstart, char **psaved_start, int *poval)
+{
+ unsigned char *cp;
+ int oval; /* octet value */
+ int type; /* token value */
+
+ /*
+ * Return a literal, error, or EOF token. Update the read pointer to the
+ * start of the next token or leave it at the string terminator.
+ */
+#define IP_MATCH_RETURN_TOK(next, type) \
+ do { *pstart = (char *) (next); return (type); } while (0)
+
+ /*
+ * Return a token that contains an IPv4 address octet value.
+ */
+#define IP_MATCH_RETURN_TOK_VAL(next, type, oval) do { \
+ *poval = (oval); IP_MATCH_RETURN_TOK((next), type); \
+ } while (0)
+
+ /*
+ * Light-weight tokenizer. Each result is an IPv4 address octet value, a
+ * literal character value, error, or EOF.
+ */
+ *psaved_start = *pstart;
+ cp = (unsigned char *) *pstart;
+ if (ISDIGIT(*cp)) {
+ oval = *cp - '0';
+ type = IP_MATCH_CODE_OVAL;
+ for (cp += 1; ISDIGIT(*cp); cp++) {
+ oval *= 10;
+ oval += *cp - '0';
+ if (oval > 255)
+ type = IP_MATCH_CODE_ERR;
+ }
+ IP_MATCH_RETURN_TOK_VAL(cp, type, oval);
+ } else {
+ IP_MATCH_RETURN_TOK(*cp ? cp + 1 : cp, *cp);
+ }
+}
+
+/* ipmatch_print_parse_error - formatted parsing error, with context */
+
+static void PRINTFLIKE(5, 6) ipmatch_print_parse_error(VSTRING *reply,
+ char *start,
+ char *here,
+ char *next,
+ const char *fmt,...)
+{
+ va_list ap;
+ int start_width;
+ int here_width;
+
+ /*
+ * Format the error type.
+ */
+ va_start(ap, fmt);
+ vstring_vsprintf(reply, fmt, ap);
+ va_end(ap);
+
+ /*
+ * Format the error context. The syntax is complex enough that it is
+ * worth the effort to precisely indicate what input is in error.
+ *
+ * XXX Workaround for %.*s to avoid output when a zero width is specified.
+ */
+ if (start != 0) {
+ start_width = here - start;
+ here_width = next - here;
+ vstring_sprintf_append(reply, " at \"%.*s>%.*s<%s\"",
+ start_width, start_width == 0 ? "" : start,
+ here_width, here_width == 0 ? "" : here, next);
+ }
+}
+
+/* ip_match_parse - parse an entire wild-card address pattern */
+
+char *ip_match_parse(VSTRING *byte_codes, char *pattern)
+{
+ int octet_count;
+ char *saved_cp;
+ char *cp;
+ int token_type;
+ int look_ahead;
+ int oval;
+ int saved_oval;
+
+ /*
+ * Simplify this if we change to {} for wildcard notation.
+ */
+#define FIND_TERMINATOR(start, cp) do { \
+ int _level = 0; \
+ for (cp = (start) ; *cp; cp++) { \
+ if (*cp == '[') _level++; \
+ if (*cp != ']') continue; \
+ if (--_level == 0) break; \
+ } \
+ } while (0)
+
+ /*
+ * Strip [] around the entire pattern.
+ */
+ if (*pattern == '[') {
+ FIND_TERMINATOR(pattern, cp);
+ if (cp[0] == 0) {
+ vstring_sprintf(byte_codes, "missing \"]\" character");
+ return (STR(byte_codes));
+ }
+ if (cp[1] == 0) {
+ *cp = 0;
+ pattern += 1;
+ }
+ }
+
+ /*
+ * Sanity check. In this case we can't show any error context.
+ */
+ if (*pattern == 0) {
+ vstring_sprintf(byte_codes, "empty address pattern");
+ return (STR(byte_codes));
+ }
+
+ /*
+ * Simple parser with on-the-fly encoding. For now, IPv4 support only.
+ * Use different parser loops for IPv4 and IPv6.
+ */
+ VSTRING_RESET(byte_codes);
+ VSTRING_ADDCH(byte_codes, AF_INET);
+ octet_count = 0;
+ cp = pattern;
+
+ /*
+ * Require four address fields separated by ".", each field containing a
+ * numeric octet value or a sequence inside []. The loop head has no test
+ * and does not step the loop variable. The tokenizer advances the loop
+ * variable, and the loop termination logic is inside the loop.
+ */
+ for (;;) {
+ switch (token_type = ip_match_next_token(&cp, &saved_cp, &oval)) {
+
+ /*
+ * Numeric address field.
+ */
+ case IP_MATCH_CODE_OVAL:
+ VSTRING_ADDCH(byte_codes, IP_MATCH_CODE_OVAL);
+ VSTRING_ADDCH(byte_codes, oval);
+ break;
+
+ /*
+ * Wild-card address field.
+ */
+ case IP_MATCH_CODE_OPEN:
+ VSTRING_ADDCH(byte_codes, IP_MATCH_CODE_OPEN);
+ /* Require ";"-separated numbers or numeric ranges. */
+ for (;;) {
+ token_type = ip_match_next_token(&cp, &saved_cp, &oval);
+ if (token_type == IP_MATCH_CODE_OVAL) {
+ saved_oval = oval;
+ look_ahead = ip_match_next_token(&cp, &saved_cp, &oval);
+ /* Numeric range. */
+ if (look_ahead == '.') {
+ /* Brute-force parsing. */
+ if (ip_match_next_token(&cp, &saved_cp, &oval) == '.'
+ && ip_match_next_token(&cp, &saved_cp, &oval)
+ == IP_MATCH_CODE_OVAL
+ && saved_oval <= oval) {
+ VSTRING_ADDCH(byte_codes, IP_MATCH_CODE_RANGE);
+ VSTRING_ADDCH(byte_codes, saved_oval);
+ VSTRING_ADDCH(byte_codes, oval);
+ look_ahead =
+ ip_match_next_token(&cp, &saved_cp, &oval);
+ } else {
+ ipmatch_print_parse_error(byte_codes, pattern,
+ saved_cp, cp,
+ "numeric range error");
+ return (STR(byte_codes));
+ }
+ }
+ /* Single number. */
+ else {
+ VSTRING_ADDCH(byte_codes, IP_MATCH_CODE_OVAL);
+ VSTRING_ADDCH(byte_codes, saved_oval);
+ }
+ /* Require ";" or end-of-wildcard. */
+ token_type = look_ahead;
+ if (token_type == ';') {
+ continue;
+ } else if (token_type == IP_MATCH_CODE_CLOSE) {
+ break;
+ } else {
+ ipmatch_print_parse_error(byte_codes, pattern,
+ saved_cp, cp,
+ "need \";\" or \"%c\"",
+ IP_MATCH_CODE_CLOSE);
+ return (STR(byte_codes));
+ }
+ } else {
+ ipmatch_print_parse_error(byte_codes, pattern, saved_cp, cp,
+ "need decimal number 0..255");
+ return (STR(byte_codes));
+ }
+ }
+ VSTRING_ADDCH(byte_codes, IP_MATCH_CODE_CLOSE);
+ break;
+
+ /*
+ * Invalid field.
+ */
+ default:
+ ipmatch_print_parse_error(byte_codes, pattern, saved_cp, cp,
+ "need decimal number 0..255 or \"%c\"",
+ IP_MATCH_CODE_OPEN);
+ return (STR(byte_codes));
+ }
+ octet_count += 1;
+
+ /*
+ * Require four address fields. Not one more, not one less.
+ */
+ if (octet_count == 4) {
+ if (*cp != 0) {
+ (void) ip_match_next_token(&cp, &saved_cp, &oval);
+ ipmatch_print_parse_error(byte_codes, pattern, saved_cp, cp,
+ "garbage after pattern");
+ return (STR(byte_codes));
+ }
+ VSTRING_ADDCH(byte_codes, 0);
+ return (0);
+ }
+
+ /*
+ * Require "." before the next address field.
+ */
+ if (ip_match_next_token(&cp, &saved_cp, &oval) != '.') {
+ ipmatch_print_parse_error(byte_codes, pattern, saved_cp, cp,
+ "need \".\"");
+ return (STR(byte_codes));
+ }
+ }
+}
+
+#ifdef TEST
+
+ /*
+ * Dummy main program for regression tests.
+ */
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <vstream.h>
+#include <vstring_vstream.h>
+#include <stringops.h>
+
+int main(int argc, char **argv)
+{
+ VSTRING *byte_codes = vstring_alloc(100);
+ VSTRING *line_buf = vstring_alloc(100);
+ char *bufp;
+ char *err;
+ char *user_pattern;
+ char *user_address;
+ int echo_input = !isatty(0);
+
+ /*
+ * Iterate over the input stream. The input format is a pattern, followed
+ * by optional addresses to match against.
+ */
+ while (vstring_fgets_nonl(line_buf, VSTREAM_IN)) {
+ bufp = STR(line_buf);
+ if (echo_input) {
+ vstream_printf("> %s\n", bufp);
+ vstream_fflush(VSTREAM_OUT);
+ }
+ if (*bufp == '#')
+ continue;
+ if ((user_pattern = mystrtok(&bufp, " \t")) == 0)
+ continue;
+
+ /*
+ * Parse and dump the pattern.
+ */
+ if ((err = ip_match_parse(byte_codes, user_pattern)) != 0) {
+ vstream_printf("Error: %s\n", err);
+ } else {
+ vstream_printf("Code: %s\n",
+ ip_match_dump(line_buf, STR(byte_codes)));
+ }
+ vstream_fflush(VSTREAM_OUT);
+
+ /*
+ * Match the optional patterns.
+ */
+ while ((user_address = mystrtok(&bufp, " \t")) != 0) {
+ struct in_addr netw_addr;
+
+ switch (inet_pton(AF_INET, user_address, &netw_addr)) {
+ case 1:
+ vstream_printf("Match %s: %s\n", user_address,
+ ip_match_execute(STR(byte_codes),
+ (char *) &netw_addr.s_addr) ?
+ "yes" : "no");
+ break;
+ case 0:
+ vstream_printf("bad address syntax: %s\n", user_address);
+ break;
+ case -1:
+ vstream_printf("%s: %m\n", user_address);
+ break;
+ }
+ vstream_fflush(VSTREAM_OUT);
+ }
+ }
+ vstring_free(line_buf);
+ vstring_free(byte_codes);
+ exit(0);
+}
+
+#endif
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