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Diffstat (limited to 'src/util/midna_domain.c')
| -rw-r--r-- | src/util/midna_domain.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/src/util/midna_domain.c b/src/util/midna_domain.c new file mode 100644 index 0000000..333a5c9 --- /dev/null +++ b/src/util/midna_domain.c @@ -0,0 +1,419 @@ +/*++ +/* NAME +/* midna_domain 3 +/* SUMMARY +/* ASCII/UTF-8 domain name conversion +/* SYNOPSIS +/* #include <midna_domain.h> +/* +/* int midna_domain_cache_size; +/* int midna_domain_transitional; +/* +/* const char *midna_domain_to_ascii( +/* const char *name) +/* +/* const char *midna_domain_to_utf8( +/* const char *name) +/* +/* const char *midna_domain_suffix_to_ascii( +/* const char *name) +/* +/* const char *midna_domain_suffix_to_utf8( +/* const char *name) +/* AUXILIARY FUNCTIONS +/* void midna_domain_pre_chroot(void) +/* DESCRIPTION +/* The functions in this module transform domain names from/to +/* ASCII and UTF-8 form. The result is cached to avoid repeated +/* conversion. +/* +/* This module builds on the ICU library implementation of the +/* UTS #46 specification, using default ICU library options +/* because those are likely best tested: with transitional +/* processing, with case mapping, with normalization, with +/* limited IDNA2003 compatibility, without STD3 ASCII rules. +/* +/* midna_domain_to_ascii() converts an UTF-8 or ASCII domain +/* name to ASCII. The result is a null pointer in case of +/* error. This function verifies that the result passes +/* valid_hostname(). +/* +/* midna_domain_to_utf8() converts an UTF-8 or ASCII domain +/* name to UTF-8. The result is a null pointer in case of +/* error. This function verifies that the result, after +/* conversion to ASCII, passes valid_hostname(). +/* +/* midna_domain_suffix_to_ascii() and midna_domain_suffix_to_utf8() +/* take a name that starts with '.' and otherwise perform the +/* same operations as midna_domain_to_ascii() and +/* midna_domain_to_utf8(). +/* +/* midna_domain_cache_size specifies the size of the conversion +/* result cache. This value is used only once, upon the first +/* lookup request. +/* +/* midna_domain_transitional enables transitional conversion +/* between UTF8 and ASCII labels. +/* +/* midna_domain_pre_chroot() does some pre-chroot initialization. +/* SEE ALSO +/* http://unicode.org/reports/tr46/ Unicode IDNA Compatibility processing +/* msg(3) diagnostics interface +/* DIAGNOSTICS +/* Fatal errors: memory allocation problem. +/* Warnings: conversion error or result validation error. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Arnt Gulbrandsen +/* +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/* +/* Wietse Venema +/* Google, Inc. +/* 111 8th Avenue +/* New York, NY 10011, USA +/*--*/ + + /* + * System library. + */ +#include <sys_defs.h> +#include <string.h> +#include <ctype.h> + +#ifndef NO_EAI +#include <unicode/uidna.h> + + /* + * Utility library. + */ +#include <mymalloc.h> +#include <msg.h> +#include <ctable.h> +#include <stringops.h> +#include <valid_hostname.h> +#include <name_mask.h> +#include <midna_domain.h> + + /* + * Application-specific. + */ +#define DEF_MIDNA_CACHE_SIZE 256 + +int midna_domain_cache_size = DEF_MIDNA_CACHE_SIZE; +int midna_domain_transitional = 0; +static VSTRING *midna_domain_buf; /* x.suffix */ + +#define STR(x) vstring_str(x) + +/* midna_domain_strerror - pick one for error reporting */ + +static const char *midna_domain_strerror(UErrorCode error, int info_errors) +{ + + /* + * XXX The UIDNA_ERROR_EMPTY_LABEL etc. names are defined in an ENUM, so + * we can't use #ifdef to dynamically determine which names exist. + */ + static LONG_NAME_MASK uidna_errors[] = { + "UIDNA_ERROR_EMPTY_LABEL", UIDNA_ERROR_EMPTY_LABEL, + "UIDNA_ERROR_LABEL_TOO_LONG", UIDNA_ERROR_LABEL_TOO_LONG, + "UIDNA_ERROR_DOMAIN_NAME_TOO_LONG", UIDNA_ERROR_DOMAIN_NAME_TOO_LONG, + "UIDNA_ERROR_LEADING_HYPHEN", UIDNA_ERROR_LEADING_HYPHEN, + "UIDNA_ERROR_TRAILING_HYPHEN", UIDNA_ERROR_TRAILING_HYPHEN, + "UIDNA_ERROR_HYPHEN_3_4", UIDNA_ERROR_HYPHEN_3_4, + "UIDNA_ERROR_LEADING_COMBINING_MARK", UIDNA_ERROR_LEADING_COMBINING_MARK, + "UIDNA_ERROR_DISALLOWED", UIDNA_ERROR_DISALLOWED, + "UIDNA_ERROR_PUNYCODE", UIDNA_ERROR_PUNYCODE, + "UIDNA_ERROR_LABEL_HAS_DOT", UIDNA_ERROR_LABEL_HAS_DOT, + "UIDNA_ERROR_INVALID_ACE_LABEL", UIDNA_ERROR_INVALID_ACE_LABEL, + "UIDNA_ERROR_BIDI", UIDNA_ERROR_BIDI, + "UIDNA_ERROR_CONTEXTJ", UIDNA_ERROR_CONTEXTJ, + /* The above errors are defined with ICU 46 and later. */ + 0, + }; + + if (info_errors) { + return (str_long_name_mask_opt((VSTRING *) 0, "idna error", + uidna_errors, info_errors, + NAME_MASK_NUMBER | NAME_MASK_COMMA)); + } else { + return u_errorName(error); + } +} + +/* midna_domain_pre_chroot - pre-chroot initialization */ + +void midna_domain_pre_chroot(void) +{ + UErrorCode error = U_ZERO_ERROR; + UIDNAInfo info = UIDNA_INFO_INITIALIZER; + UIDNA *idna; + + idna = uidna_openUTS46(midna_domain_transitional ? UIDNA_DEFAULT + : UIDNA_NONTRANSITIONAL_TO_ASCII, &error); + if (U_FAILURE(error)) + msg_warn("ICU library initialization failed: %s", + midna_domain_strerror(error, info.errors)); + uidna_close(idna); +} + +/* midna_domain_to_ascii_create - convert domain to ASCII */ + +static void *midna_domain_to_ascii_create(const char *name, void *unused_context) +{ + static const char myname[] = "midna_domain_to_ascii_create"; + char buf[1024]; /* XXX */ + UErrorCode error = U_ZERO_ERROR; + UIDNAInfo info = UIDNA_INFO_INITIALIZER; + UIDNA *idna; + int anl; + + /* + * Paranoia: do not expose uidna_*() to unfiltered network data. + */ + if (allascii(name) == 0 && valid_utf8_string(name, strlen(name)) == 0) { + msg_warn("%s: Problem translating domain \"%.100s\" to ASCII form: %s", + myname, name, "malformed UTF-8"); + return (0); + } + + /* + * Perform the requested conversion. + */ + idna = uidna_openUTS46(midna_domain_transitional ? UIDNA_DEFAULT + : UIDNA_NONTRANSITIONAL_TO_ASCII, &error); + anl = uidna_nameToASCII_UTF8(idna, + name, strlen(name), + buf, sizeof(buf) - 1, + &info, + &error); + uidna_close(idna); + + /* + * Paranoia: verify that the result passes valid_hostname(). A quick + * check shows that UTS46 ToASCII by default rejects inputs with labels + * that start or end in '-', with names or labels that are over-long, or + * "fake" A-labels, as required by UTS 46 section 4.1, but we rely on + * valid_hostname() on the output side just to be sure. + */ + if (U_SUCCESS(error) && info.errors == 0 && anl > 0) { + buf[anl] = 0; /* XXX */ + if (!valid_hostname(buf, DONT_GRIPE)) { + msg_warn("%s: Problem translating domain \"%.100s\" to ASCII form: %s", + myname, name, "malformed ASCII label(s)"); + return (0); + } + return (mystrndup(buf, anl)); + } else { + msg_warn("%s: Problem translating domain \"%.100s\" to ASCII form: %s", + myname, name, midna_domain_strerror(error, info.errors)); + return (0); + } +} + +/* midna_domain_to_utf8_create - convert domain to UTF8 */ + +static void *midna_domain_to_utf8_create(const char *name, void *unused_context) +{ + static const char myname[] = "midna_domain_to_utf8_create"; + char buf[1024]; /* XXX */ + UErrorCode error = U_ZERO_ERROR; + UIDNAInfo info = UIDNA_INFO_INITIALIZER; + UIDNA *idna; + int anl; + + /* + * Paranoia: do not expose uidna_*() to unfiltered network data. + */ + if (allascii(name) == 0 && valid_utf8_string(name, strlen(name)) == 0) { + msg_warn("%s: Problem translating domain \"%.100s\" to UTF-8 form: %s", + myname, name, "malformed UTF-8"); + return (0); + } + + /* + * Perform the requested conversion. + */ + idna = uidna_openUTS46(midna_domain_transitional ? UIDNA_DEFAULT + : UIDNA_NONTRANSITIONAL_TO_UNICODE, &error); + anl = uidna_nameToUnicodeUTF8(idna, + name, strlen(name), + buf, sizeof(buf) - 1, + &info, + &error); + uidna_close(idna); + + /* + * Paranoia: UTS46 toUTF8 by default accepts and produces an over-long + * name or a name that contains an over-long NR-LDH label (and perhaps + * other invalid forms that are not covered in UTS 46, section 4.1). We + * rely on midna_domain_to_ascii() to validate the output. + */ + if (U_SUCCESS(error) && info.errors == 0 && anl > 0) { + buf[anl] = 0; /* XXX */ + if (midna_domain_to_ascii(buf) == 0) + return (0); + return (mystrndup(buf, anl)); + } else { + msg_warn("%s: Problem translating domain \"%.100s\" to UTF8 form: %s", + myname, name, midna_domain_strerror(error, info.errors)); + return (0); + } +} + +/* midna_domain_cache_free - cache element destructor */ + +static void midna_domain_cache_free(void *value, void *unused_context) +{ + if (value) + myfree(value); +} + +/* midna_domain_to_ascii - convert name to ASCII */ + +const char *midna_domain_to_ascii(const char *name) +{ + static CTABLE *midna_domain_to_ascii_cache = 0; + + if (midna_domain_to_ascii_cache == 0) + midna_domain_to_ascii_cache = ctable_create(midna_domain_cache_size, + midna_domain_to_ascii_create, + midna_domain_cache_free, + (void *) 0); + return (ctable_locate(midna_domain_to_ascii_cache, name)); +} + +/* midna_domain_to_utf8 - convert name to UTF8 */ + +const char *midna_domain_to_utf8(const char *name) +{ + static CTABLE *midna_domain_to_utf8_cache = 0; + + if (midna_domain_to_utf8_cache == 0) + midna_domain_to_utf8_cache = ctable_create(midna_domain_cache_size, + midna_domain_to_utf8_create, + midna_domain_cache_free, + (void *) 0); + return (ctable_locate(midna_domain_to_utf8_cache, name)); +} + +/* midna_domain_suffix_to_ascii - convert .name to ASCII */ + +const char *midna_domain_suffix_to_ascii(const char *suffix) +{ + const char *cache_res; + + /* + * If prepending x to .name causes the result to become too long, then + * the suffix is bad. + */ + if (midna_domain_buf == 0) + midna_domain_buf = vstring_alloc(100); + vstring_sprintf(midna_domain_buf, "x%s", suffix); + if ((cache_res = midna_domain_to_ascii(STR(midna_domain_buf))) == 0) + return (0); + else + return (cache_res + 1); +} + +/* midna_domain_suffix_to_utf8 - convert .name to UTF8 */ + +const char *midna_domain_suffix_to_utf8(const char *name) +{ + const char *cache_res; + + /* + * If prepending x to .name causes the result to become too long, then + * the suffix is bad. + */ + if (midna_domain_buf == 0) + midna_domain_buf = vstring_alloc(100); + vstring_sprintf(midna_domain_buf, "x%s", name); + if ((cache_res = midna_domain_to_utf8(STR(midna_domain_buf))) == 0) + return (0); + else + return (cache_res + 1); +} + +#ifdef TEST + + /* + * Test program - reads names from stdin, reports invalid names to stderr. + */ +#include <unistd.h> +#include <stdlib.h> +#include <locale.h> + +#include <stringops.h> /* XXX util_utf8_enable */ +#include <vstring.h> +#include <vstream.h> +#include <vstring_vstream.h> +#include <msg_vstream.h> + +int main(int argc, char **argv) +{ + VSTRING *buffer = vstring_alloc(1); + const char *bp; + const char *ascii; + const char *utf8; + + if (setlocale(LC_ALL, "C") == 0) + msg_fatal("setlocale(LC_ALL, C) failed: %m"); + + msg_vstream_init(argv[0], VSTREAM_ERR); + /* msg_verbose = 1; */ + util_utf8_enable = 1; + + if (geteuid() == 0) { + midna_domain_pre_chroot(); + if (chroot(".") != 0) + msg_fatal("chroot(\".\"): %m"); + } + while (vstring_fgets_nonl(buffer, VSTREAM_IN)) { + bp = STR(buffer); + msg_info("> %s", bp); + while (ISSPACE(*bp)) + bp++; + if (*bp == '#' || *bp == 0) + continue; + msg_info("unconditional conversions:"); + utf8 = midna_domain_to_utf8(bp); + msg_info("\"%s\" ->utf8 \"%s\"", bp, utf8 ? utf8 : "(error)"); + ascii = midna_domain_to_ascii(bp); + msg_info("\"%s\" ->ascii \"%s\"", bp, ascii ? ascii : "(error)"); + msg_info("conditional conversions:"); + if (!allascii(bp)) { + if (ascii != 0) { + utf8 = midna_domain_to_utf8(ascii); + msg_info("\"%s\" ->ascii \"%s\" ->utf8 \"%s\"", + bp, ascii, utf8 ? utf8 : "(error)"); + if (utf8 != 0) { + if (strcmp(utf8, bp) != 0) + msg_warn("\"%s\" != \"%s\"", bp, utf8); + } + } + } else { + if (utf8 != 0) { + ascii = midna_domain_to_ascii(utf8); + msg_info("\"%s\" ->utf8 \"%s\" ->ascii \"%s\"", + bp, utf8, ascii ? ascii : "(error)"); + if (ascii != 0) { + if (strcmp(ascii, bp) != 0) + msg_warn("\"%s\" != \"%s\"", bp, ascii); + } + } + } + } + exit(0); +} + +#endif /* TEST */ + +#endif /* NO_EAI */ |