diff options
Diffstat (limited to 'urlmatch.c')
| -rw-r--r-- | urlmatch.c | 535 |
1 files changed, 535 insertions, 0 deletions
diff --git a/urlmatch.c b/urlmatch.c new file mode 100644 index 0000000..1db76c8 --- /dev/null +++ b/urlmatch.c @@ -0,0 +1,535 @@ +#include "cache.h" +#include "urlmatch.h" + +#define URL_ALPHA "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" +#define URL_DIGIT "0123456789" +#define URL_ALPHADIGIT URL_ALPHA URL_DIGIT +#define URL_SCHEME_CHARS URL_ALPHADIGIT "+.-" +#define URL_HOST_CHARS URL_ALPHADIGIT ".-[:]" /* IPv6 literals need [:] */ +#define URL_UNSAFE_CHARS " <>\"%{}|\\^`" /* plus 0x00-0x1F,0x7F-0xFF */ +#define URL_GEN_RESERVED ":/?#[]@" +#define URL_SUB_RESERVED "!$&'()*+,;=" +#define URL_RESERVED URL_GEN_RESERVED URL_SUB_RESERVED /* only allowed delims */ + +static int append_normalized_escapes(struct strbuf *buf, + const char *from, + size_t from_len, + const char *esc_extra, + const char *esc_ok) +{ + /* + * Append to strbuf 'buf' characters from string 'from' with length + * 'from_len' while unescaping characters that do not need to be escaped + * and escaping characters that do. The set of characters to escape + * (the complement of which is unescaped) starts out as the RFC 3986 + * unsafe characters (0x00-0x1F,0x7F-0xFF," <>\"#%{}|\\^`"). If + * 'esc_extra' is not NULL, those additional characters will also always + * be escaped. If 'esc_ok' is not NULL, those characters will be left + * escaped if found that way, but will not be unescaped otherwise (used + * for delimiters). If a %-escape sequence is encountered that is not + * followed by 2 hexadecimal digits, the sequence is invalid and + * false (0) will be returned. Otherwise true (1) will be returned for + * success. + * + * Note that all %-escape sequences will be normalized to UPPERCASE + * as indicated in RFC 3986. Unless included in esc_extra or esc_ok + * alphanumerics and "-._~" will always be unescaped as per RFC 3986. + */ + + while (from_len) { + int ch = *from++; + int was_esc = 0; + + from_len--; + if (ch == '%') { + if (from_len < 2 || + !isxdigit((unsigned char)from[0]) || + !isxdigit((unsigned char)from[1])) + return 0; + ch = hexval_table[(unsigned char)*from++] << 4; + ch |= hexval_table[(unsigned char)*from++]; + from_len -= 2; + was_esc = 1; + } + if ((unsigned char)ch <= 0x1F || (unsigned char)ch >= 0x7F || + strchr(URL_UNSAFE_CHARS, ch) || + (esc_extra && strchr(esc_extra, ch)) || + (was_esc && strchr(esc_ok, ch))) + strbuf_addf(buf, "%%%02X", (unsigned char)ch); + else + strbuf_addch(buf, ch); + } + + return 1; +} + +char *url_normalize(const char *url, struct url_info *out_info) +{ + /* + * Normalize NUL-terminated url using the following rules: + * + * 1. Case-insensitive parts of url will be converted to lower case + * 2. %-encoded characters that do not need to be will be unencoded + * 3. Characters that are not %-encoded and must be will be encoded + * 4. All %-encodings will be converted to upper case hexadecimal + * 5. Leading 0s are removed from port numbers + * 6. If the default port for the scheme is given it will be removed + * 7. A path part (including empty) not starting with '/' has one added + * 8. Any dot segments (. or ..) in the path are resolved and removed + * 9. IPv6 host literals are allowed (but not normalized or validated) + * + * The rules are based on information in RFC 3986. + * + * Please note this function requires a full URL including a scheme + * and host part (except for file: URLs which may have an empty host). + * + * The return value is a newly allocated string that must be freed + * or NULL if the url is not valid. + * + * If out_info is non-NULL, the url and err fields therein will always + * be set. If a non-NULL value is returned, it will be stored in + * out_info->url as well, out_info->err will be set to NULL and the + * other fields of *out_info will also be filled in. If a NULL value + * is returned, NULL will be stored in out_info->url and out_info->err + * will be set to a brief, translated, error message, but no other + * fields will be filled in. + * + * This is NOT a URL validation function. Full URL validation is NOT + * performed. Some invalid host names are passed through this function + * undetected. However, most all other problems that make a URL invalid + * will be detected (including a missing host for non file: URLs). + */ + + size_t url_len = strlen(url); + struct strbuf norm; + size_t spanned; + size_t scheme_len, user_off=0, user_len=0, passwd_off=0, passwd_len=0; + size_t host_off=0, host_len=0, port_len=0, path_off, path_len, result_len; + const char *slash_ptr, *at_ptr, *colon_ptr, *path_start; + char *result; + + /* + * Copy lowercased scheme and :// suffix, %-escapes are not allowed + * First character of scheme must be URL_ALPHA + */ + spanned = strspn(url, URL_SCHEME_CHARS); + if (!spanned || !isalpha(url[0]) || spanned + 3 > url_len || + url[spanned] != ':' || url[spanned+1] != '/' || url[spanned+2] != '/') { + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid URL scheme name or missing '://' suffix"); + } + return NULL; /* Bad scheme and/or missing "://" part */ + } + strbuf_init(&norm, url_len); + scheme_len = spanned; + spanned += 3; + url_len -= spanned; + while (spanned--) + strbuf_addch(&norm, tolower(*url++)); + + + /* + * Copy any username:password if present normalizing %-escapes + */ + at_ptr = strchr(url, '@'); + slash_ptr = url + strcspn(url, "/?#"); + if (at_ptr && at_ptr < slash_ptr) { + user_off = norm.len; + if (at_ptr > url) { + if (!append_normalized_escapes(&norm, url, at_ptr - url, + "", URL_RESERVED)) { + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid %XX escape sequence"); + } + strbuf_release(&norm); + return NULL; + } + colon_ptr = strchr(norm.buf + scheme_len + 3, ':'); + if (colon_ptr) { + passwd_off = (colon_ptr + 1) - norm.buf; + passwd_len = norm.len - passwd_off; + user_len = (passwd_off - 1) - (scheme_len + 3); + } else { + user_len = norm.len - (scheme_len + 3); + } + } + strbuf_addch(&norm, '@'); + url_len -= (++at_ptr - url); + url = at_ptr; + } + + + /* + * Copy the host part excluding any port part, no %-escapes allowed + */ + if (!url_len || strchr(":/?#", *url)) { + /* Missing host invalid for all URL schemes except file */ + if (strncmp(norm.buf, "file:", 5)) { + if (out_info) { + out_info->url = NULL; + out_info->err = _("missing host and scheme is not 'file:'"); + } + strbuf_release(&norm); + return NULL; + } + } else { + host_off = norm.len; + } + colon_ptr = slash_ptr - 1; + while (colon_ptr > url && *colon_ptr != ':' && *colon_ptr != ']') + colon_ptr--; + if (*colon_ptr != ':') { + colon_ptr = slash_ptr; + } else if (!host_off && colon_ptr < slash_ptr && colon_ptr + 1 != slash_ptr) { + /* file: URLs may not have a port number */ + if (out_info) { + out_info->url = NULL; + out_info->err = _("a 'file:' URL may not have a port number"); + } + strbuf_release(&norm); + return NULL; + } + spanned = strspn(url, URL_HOST_CHARS); + if (spanned < colon_ptr - url) { + /* Host name has invalid characters */ + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid characters in host name"); + } + strbuf_release(&norm); + return NULL; + } + while (url < colon_ptr) { + strbuf_addch(&norm, tolower(*url++)); + url_len--; + } + + + /* + * Check the port part and copy if not the default (after removing any + * leading 0s); no %-escapes allowed + */ + if (colon_ptr < slash_ptr) { + /* skip the ':' and leading 0s but not the last one if all 0s */ + url++; + url += strspn(url, "0"); + if (url == slash_ptr && url[-1] == '0') + url--; + if (url == slash_ptr) { + /* Skip ":" port with no number, it's same as default */ + } else if (slash_ptr - url == 2 && + !strncmp(norm.buf, "http:", 5) && + !strncmp(url, "80", 2)) { + /* Skip http :80 as it's the default */ + } else if (slash_ptr - url == 3 && + !strncmp(norm.buf, "https:", 6) && + !strncmp(url, "443", 3)) { + /* Skip https :443 as it's the default */ + } else { + /* + * Port number must be all digits with leading 0s removed + * and since all the protocols we deal with have a 16-bit + * port number it must also be in the range 1..65535 + * 0 is not allowed because that means "next available" + * on just about every system and therefore cannot be used + */ + unsigned long pnum = 0; + spanned = strspn(url, URL_DIGIT); + if (spanned < slash_ptr - url) { + /* port number has invalid characters */ + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid port number"); + } + strbuf_release(&norm); + return NULL; + } + if (slash_ptr - url <= 5) + pnum = strtoul(url, NULL, 10); + if (pnum == 0 || pnum > 65535) { + /* port number not in range 1..65535 */ + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid port number"); + } + strbuf_release(&norm); + return NULL; + } + strbuf_addch(&norm, ':'); + strbuf_add(&norm, url, slash_ptr - url); + port_len = slash_ptr - url; + } + url_len -= slash_ptr - colon_ptr; + url = slash_ptr; + } + if (host_off) + host_len = norm.len - host_off; + + + /* + * Now copy the path resolving any . and .. segments being careful not + * to corrupt the URL by unescaping any delimiters, but do add an + * initial '/' if it's missing and do normalize any %-escape sequences. + */ + path_off = norm.len; + path_start = norm.buf + path_off; + strbuf_addch(&norm, '/'); + if (*url == '/') { + url++; + url_len--; + } + for (;;) { + const char *seg_start = norm.buf + norm.len; + const char *next_slash = url + strcspn(url, "/?#"); + int skip_add_slash = 0; + /* + * RFC 3689 indicates that any . or .. segments should be + * unescaped before being checked for. + */ + if (!append_normalized_escapes(&norm, url, next_slash - url, "", + URL_RESERVED)) { + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid %XX escape sequence"); + } + strbuf_release(&norm); + return NULL; + } + if (!strcmp(seg_start, ".")) { + /* ignore a . segment; be careful not to remove initial '/' */ + if (seg_start == path_start + 1) { + strbuf_setlen(&norm, norm.len - 1); + skip_add_slash = 1; + } else { + strbuf_setlen(&norm, norm.len - 2); + } + } else if (!strcmp(seg_start, "..")) { + /* + * ignore a .. segment and remove the previous segment; + * be careful not to remove initial '/' from path + */ + const char *prev_slash = norm.buf + norm.len - 3; + if (prev_slash == path_start) { + /* invalid .. because no previous segment to remove */ + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid '..' path segment"); + } + strbuf_release(&norm); + return NULL; + } + while (*--prev_slash != '/') {} + if (prev_slash == path_start) { + strbuf_setlen(&norm, prev_slash - norm.buf + 1); + skip_add_slash = 1; + } else { + strbuf_setlen(&norm, prev_slash - norm.buf); + } + } + url_len -= next_slash - url; + url = next_slash; + /* if the next char is not '/' done with the path */ + if (*url != '/') + break; + url++; + url_len--; + if (!skip_add_slash) + strbuf_addch(&norm, '/'); + } + path_len = norm.len - path_off; + + + /* + * Now simply copy the rest, if any, only normalizing %-escapes and + * being careful not to corrupt the URL by unescaping any delimiters. + */ + if (*url) { + if (!append_normalized_escapes(&norm, url, url_len, "", URL_RESERVED)) { + if (out_info) { + out_info->url = NULL; + out_info->err = _("invalid %XX escape sequence"); + } + strbuf_release(&norm); + return NULL; + } + } + + + result = strbuf_detach(&norm, &result_len); + if (out_info) { + out_info->url = result; + out_info->err = NULL; + out_info->url_len = result_len; + out_info->scheme_len = scheme_len; + out_info->user_off = user_off; + out_info->user_len = user_len; + out_info->passwd_off = passwd_off; + out_info->passwd_len = passwd_len; + out_info->host_off = host_off; + out_info->host_len = host_len; + out_info->port_len = port_len; + out_info->path_off = path_off; + out_info->path_len = path_len; + } + return result; +} + +static size_t url_match_prefix(const char *url, + const char *url_prefix, + size_t url_prefix_len) +{ + /* + * url_prefix matches url if url_prefix is an exact match for url or it + * is a prefix of url and the match ends on a path component boundary. + * Both url and url_prefix are considered to have an implicit '/' on the + * end for matching purposes if they do not already. + * + * url must be NUL terminated. url_prefix_len is the length of + * url_prefix which need not be NUL terminated. + * + * The return value is the length of the match in characters (including + * the final '/' even if it's implicit) or 0 for no match. + * + * Passing NULL as url and/or url_prefix will always cause 0 to be + * returned without causing any faults. + */ + if (!url || !url_prefix) + return 0; + if (!url_prefix_len || (url_prefix_len == 1 && *url_prefix == '/')) + return (!*url || *url == '/') ? 1 : 0; + if (url_prefix[url_prefix_len - 1] == '/') + url_prefix_len--; + if (strncmp(url, url_prefix, url_prefix_len)) + return 0; + if ((strlen(url) == url_prefix_len) || (url[url_prefix_len] == '/')) + return url_prefix_len + 1; + return 0; +} + +int match_urls(const struct url_info *url, + const struct url_info *url_prefix, + int *exactusermatch) +{ + /* + * url_prefix matches url if the scheme, host and port of url_prefix + * are the same as those of url and the path portion of url_prefix + * is the same as the path portion of url or it is a prefix that + * matches at a '/' boundary. If url_prefix contains a user name, + * that must also exactly match the user name in url. + * + * If the user, host, port and path match in this fashion, the returned + * value is the length of the path match including any implicit + * final '/'. For example, "http://me@example.com/path" is matched by + * "http://example.com" with a path length of 1. + * + * If there is a match and exactusermatch is not NULL, then + * *exactusermatch will be set to true if both url and url_prefix + * contained a user name or false if url_prefix did not have a + * user name. If there is no match *exactusermatch is left untouched. + */ + int usermatched = 0; + int pathmatchlen; + + if (!url || !url_prefix || !url->url || !url_prefix->url) + return 0; + + /* check the scheme */ + if (url_prefix->scheme_len != url->scheme_len || + strncmp(url->url, url_prefix->url, url->scheme_len)) + return 0; /* schemes do not match */ + + /* check the user name if url_prefix has one */ + if (url_prefix->user_off) { + if (!url->user_off || url->user_len != url_prefix->user_len || + strncmp(url->url + url->user_off, + url_prefix->url + url_prefix->user_off, + url->user_len)) + return 0; /* url_prefix has a user but it's not a match */ + usermatched = 1; + } + + /* check the host and port */ + if (url_prefix->host_len != url->host_len || + strncmp(url->url + url->host_off, + url_prefix->url + url_prefix->host_off, url->host_len)) + return 0; /* host names and/or ports do not match */ + + /* check the path */ + pathmatchlen = url_match_prefix( + url->url + url->path_off, + url_prefix->url + url_prefix->path_off, + url_prefix->url_len - url_prefix->path_off); + + if (pathmatchlen && exactusermatch) + *exactusermatch = usermatched; + return pathmatchlen; +} + +int urlmatch_config_entry(const char *var, const char *value, void *cb) +{ + struct string_list_item *item; + struct urlmatch_config *collect = cb; + struct urlmatch_item *matched; + struct url_info *url = &collect->url; + const char *key, *dot; + struct strbuf synthkey = STRBUF_INIT; + size_t matched_len = 0; + int user_matched = 0; + int retval; + + key = skip_prefix(var, collect->section); + if (!key || *(key++) != '.') { + if (collect->cascade_fn) + return collect->cascade_fn(var, value, cb); + return 0; /* not interested */ + } + dot = strrchr(key, '.'); + if (dot) { + char *config_url, *norm_url; + struct url_info norm_info; + + config_url = xmemdupz(key, dot - key); + norm_url = url_normalize(config_url, &norm_info); + free(config_url); + if (!norm_url) + return 0; + matched_len = match_urls(url, &norm_info, &user_matched); + free(norm_url); + if (!matched_len) + return 0; + key = dot + 1; + } + + if (collect->key && strcmp(key, collect->key)) + return 0; + + item = string_list_insert(&collect->vars, key); + if (!item->util) { + matched = xcalloc(1, sizeof(*matched)); + item->util = matched; + } else { + matched = item->util; + /* + * Is our match shorter? Is our match the same + * length, and without user while the current + * candidate is with user? Then we cannot use it. + */ + if (matched_len < matched->matched_len || + ((matched_len == matched->matched_len) && + (!user_matched && matched->user_matched))) + return 0; + /* Otherwise, replace it with this one. */ + } + + matched->matched_len = matched_len; + matched->user_matched = user_matched; + strbuf_addstr(&synthkey, collect->section); + strbuf_addch(&synthkey, '.'); + strbuf_addstr(&synthkey, key); + retval = collect->collect_fn(synthkey.buf, value, collect->cb); + + strbuf_release(&synthkey); + return retval; +} |