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836b6fb5a5
Existing configuration parsing functions (e.g. http_options() in http.c) know how to parse two-level configuration variable names. We would like to exploit them and parse something like this: [http] sslVerify = true [http "https://weak.example.com"] sslVerify = false and pretend as if http.sslVerify were set to false when talking to "https://weak.example.com/path". Introduce `urlmatch_config_entry()` wrapper that: - is called with the target URL (e.g. "https://weak.example.com/path"), and the two-level variable parser (e.g. `http_options`); - uses `url_normalize()` and `match_urls()` to see if configuration data matches the target URL; and - calls the traditional two-level configuration variable parser only for the configuration data whose <url> part matches the target URL (and if there are multiple matches, only do so if the current match is a better match than the ones previously seen). Signed-off-by: Junio C Hamano <gitster@pobox.com>
535 lines
17 KiB
C
535 lines
17 KiB
C
#include "cache.h"
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#include "urlmatch.h"
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#define URL_ALPHA "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
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#define URL_DIGIT "0123456789"
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#define URL_ALPHADIGIT URL_ALPHA URL_DIGIT
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#define URL_SCHEME_CHARS URL_ALPHADIGIT "+.-"
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#define URL_HOST_CHARS URL_ALPHADIGIT ".-[:]" /* IPv6 literals need [:] */
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#define URL_UNSAFE_CHARS " <>\"%{}|\\^`" /* plus 0x00-0x1F,0x7F-0xFF */
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#define URL_GEN_RESERVED ":/?#[]@"
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#define URL_SUB_RESERVED "!$&'()*+,;="
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#define URL_RESERVED URL_GEN_RESERVED URL_SUB_RESERVED /* only allowed delims */
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static int append_normalized_escapes(struct strbuf *buf,
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const char *from,
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size_t from_len,
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const char *esc_extra,
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const char *esc_ok)
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{
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/*
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* Append to strbuf 'buf' characters from string 'from' with length
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* 'from_len' while unescaping characters that do not need to be escaped
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* and escaping characters that do. The set of characters to escape
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* (the complement of which is unescaped) starts out as the RFC 3986
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* unsafe characters (0x00-0x1F,0x7F-0xFF," <>\"#%{}|\\^`"). If
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* 'esc_extra' is not NULL, those additional characters will also always
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* be escaped. If 'esc_ok' is not NULL, those characters will be left
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* escaped if found that way, but will not be unescaped otherwise (used
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* for delimiters). If a %-escape sequence is encountered that is not
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* followed by 2 hexadecimal digits, the sequence is invalid and
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* false (0) will be returned. Otherwise true (1) will be returned for
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* success.
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*
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* Note that all %-escape sequences will be normalized to UPPERCASE
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* as indicated in RFC 3986. Unless included in esc_extra or esc_ok
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* alphanumerics and "-._~" will always be unescaped as per RFC 3986.
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*/
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while (from_len) {
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int ch = *from++;
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int was_esc = 0;
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from_len--;
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if (ch == '%') {
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if (from_len < 2 ||
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!isxdigit((unsigned char)from[0]) ||
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!isxdigit((unsigned char)from[1]))
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return 0;
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ch = hexval_table[(unsigned char)*from++] << 4;
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ch |= hexval_table[(unsigned char)*from++];
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from_len -= 2;
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was_esc = 1;
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}
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if ((unsigned char)ch <= 0x1F || (unsigned char)ch >= 0x7F ||
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strchr(URL_UNSAFE_CHARS, ch) ||
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(esc_extra && strchr(esc_extra, ch)) ||
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(was_esc && strchr(esc_ok, ch)))
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strbuf_addf(buf, "%%%02X", (unsigned char)ch);
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else
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strbuf_addch(buf, ch);
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}
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return 1;
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}
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char *url_normalize(const char *url, struct url_info *out_info)
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{
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/*
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* Normalize NUL-terminated url using the following rules:
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*
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* 1. Case-insensitive parts of url will be converted to lower case
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* 2. %-encoded characters that do not need to be will be unencoded
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* 3. Characters that are not %-encoded and must be will be encoded
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* 4. All %-encodings will be converted to upper case hexadecimal
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* 5. Leading 0s are removed from port numbers
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* 6. If the default port for the scheme is given it will be removed
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* 7. A path part (including empty) not starting with '/' has one added
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* 8. Any dot segments (. or ..) in the path are resolved and removed
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* 9. IPv6 host literals are allowed (but not normalized or validated)
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*
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* The rules are based on information in RFC 3986.
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*
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* Please note this function requires a full URL including a scheme
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* and host part (except for file: URLs which may have an empty host).
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*
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* The return value is a newly allocated string that must be freed
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* or NULL if the url is not valid.
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*
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* If out_info is non-NULL, the url and err fields therein will always
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* be set. If a non-NULL value is returned, it will be stored in
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* out_info->url as well, out_info->err will be set to NULL and the
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* other fields of *out_info will also be filled in. If a NULL value
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* is returned, NULL will be stored in out_info->url and out_info->err
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* will be set to a brief, translated, error message, but no other
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* fields will be filled in.
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*
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* This is NOT a URL validation function. Full URL validation is NOT
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* performed. Some invalid host names are passed through this function
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* undetected. However, most all other problems that make a URL invalid
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* will be detected (including a missing host for non file: URLs).
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*/
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size_t url_len = strlen(url);
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struct strbuf norm;
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size_t spanned;
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size_t scheme_len, user_off=0, user_len=0, passwd_off=0, passwd_len=0;
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size_t host_off=0, host_len=0, port_len=0, path_off, path_len, result_len;
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const char *slash_ptr, *at_ptr, *colon_ptr, *path_start;
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char *result;
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/*
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* Copy lowercased scheme and :// suffix, %-escapes are not allowed
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* First character of scheme must be URL_ALPHA
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*/
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spanned = strspn(url, URL_SCHEME_CHARS);
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if (!spanned || !isalpha(url[0]) || spanned + 3 > url_len ||
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url[spanned] != ':' || url[spanned+1] != '/' || url[spanned+2] != '/') {
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid URL scheme name or missing '://' suffix");
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}
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return NULL; /* Bad scheme and/or missing "://" part */
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}
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strbuf_init(&norm, url_len);
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scheme_len = spanned;
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spanned += 3;
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url_len -= spanned;
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while (spanned--)
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strbuf_addch(&norm, tolower(*url++));
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/*
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* Copy any username:password if present normalizing %-escapes
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*/
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at_ptr = strchr(url, '@');
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slash_ptr = url + strcspn(url, "/?#");
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if (at_ptr && at_ptr < slash_ptr) {
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user_off = norm.len;
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if (at_ptr > url) {
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if (!append_normalized_escapes(&norm, url, at_ptr - url,
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"", URL_RESERVED)) {
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid %XX escape sequence");
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}
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strbuf_release(&norm);
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return NULL;
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}
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colon_ptr = strchr(norm.buf + scheme_len + 3, ':');
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if (colon_ptr) {
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passwd_off = (colon_ptr + 1) - norm.buf;
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passwd_len = norm.len - passwd_off;
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user_len = (passwd_off - 1) - (scheme_len + 3);
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} else {
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user_len = norm.len - (scheme_len + 3);
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}
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}
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strbuf_addch(&norm, '@');
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url_len -= (++at_ptr - url);
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url = at_ptr;
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}
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/*
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* Copy the host part excluding any port part, no %-escapes allowed
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*/
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if (!url_len || strchr(":/?#", *url)) {
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/* Missing host invalid for all URL schemes except file */
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if (strncmp(norm.buf, "file:", 5)) {
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("missing host and scheme is not 'file:'");
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}
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strbuf_release(&norm);
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return NULL;
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}
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} else {
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host_off = norm.len;
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}
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colon_ptr = slash_ptr - 1;
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while (colon_ptr > url && *colon_ptr != ':' && *colon_ptr != ']')
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colon_ptr--;
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if (*colon_ptr != ':') {
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colon_ptr = slash_ptr;
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} else if (!host_off && colon_ptr < slash_ptr && colon_ptr + 1 != slash_ptr) {
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/* file: URLs may not have a port number */
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("a 'file:' URL may not have a port number");
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}
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strbuf_release(&norm);
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return NULL;
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}
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spanned = strspn(url, URL_HOST_CHARS);
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if (spanned < colon_ptr - url) {
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/* Host name has invalid characters */
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid characters in host name");
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}
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strbuf_release(&norm);
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return NULL;
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}
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while (url < colon_ptr) {
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strbuf_addch(&norm, tolower(*url++));
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url_len--;
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}
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/*
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* Check the port part and copy if not the default (after removing any
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* leading 0s); no %-escapes allowed
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*/
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if (colon_ptr < slash_ptr) {
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/* skip the ':' and leading 0s but not the last one if all 0s */
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url++;
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url += strspn(url, "0");
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if (url == slash_ptr && url[-1] == '0')
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url--;
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if (url == slash_ptr) {
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/* Skip ":" port with no number, it's same as default */
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} else if (slash_ptr - url == 2 &&
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!strncmp(norm.buf, "http:", 5) &&
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!strncmp(url, "80", 2)) {
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/* Skip http :80 as it's the default */
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} else if (slash_ptr - url == 3 &&
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!strncmp(norm.buf, "https:", 6) &&
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!strncmp(url, "443", 3)) {
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/* Skip https :443 as it's the default */
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} else {
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/*
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* Port number must be all digits with leading 0s removed
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* and since all the protocols we deal with have a 16-bit
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* port number it must also be in the range 1..65535
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* 0 is not allowed because that means "next available"
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* on just about every system and therefore cannot be used
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*/
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unsigned long pnum = 0;
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spanned = strspn(url, URL_DIGIT);
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if (spanned < slash_ptr - url) {
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/* port number has invalid characters */
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid port number");
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}
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strbuf_release(&norm);
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return NULL;
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}
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if (slash_ptr - url <= 5)
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pnum = strtoul(url, NULL, 10);
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if (pnum == 0 || pnum > 65535) {
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/* port number not in range 1..65535 */
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid port number");
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}
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strbuf_release(&norm);
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return NULL;
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}
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strbuf_addch(&norm, ':');
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strbuf_add(&norm, url, slash_ptr - url);
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port_len = slash_ptr - url;
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}
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url_len -= slash_ptr - colon_ptr;
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url = slash_ptr;
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}
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if (host_off)
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host_len = norm.len - host_off;
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/*
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* Now copy the path resolving any . and .. segments being careful not
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* to corrupt the URL by unescaping any delimiters, but do add an
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* initial '/' if it's missing and do normalize any %-escape sequences.
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*/
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path_off = norm.len;
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path_start = norm.buf + path_off;
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strbuf_addch(&norm, '/');
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if (*url == '/') {
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url++;
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url_len--;
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}
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for (;;) {
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const char *seg_start = norm.buf + norm.len;
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const char *next_slash = url + strcspn(url, "/?#");
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int skip_add_slash = 0;
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/*
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* RFC 3689 indicates that any . or .. segments should be
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* unescaped before being checked for.
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*/
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if (!append_normalized_escapes(&norm, url, next_slash - url, "",
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URL_RESERVED)) {
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid %XX escape sequence");
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}
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strbuf_release(&norm);
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return NULL;
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}
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if (!strcmp(seg_start, ".")) {
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/* ignore a . segment; be careful not to remove initial '/' */
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if (seg_start == path_start + 1) {
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strbuf_setlen(&norm, norm.len - 1);
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skip_add_slash = 1;
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} else {
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strbuf_setlen(&norm, norm.len - 2);
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}
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} else if (!strcmp(seg_start, "..")) {
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/*
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* ignore a .. segment and remove the previous segment;
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* be careful not to remove initial '/' from path
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*/
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const char *prev_slash = norm.buf + norm.len - 3;
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if (prev_slash == path_start) {
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/* invalid .. because no previous segment to remove */
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid '..' path segment");
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}
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strbuf_release(&norm);
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return NULL;
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}
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while (*--prev_slash != '/') {}
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if (prev_slash == path_start) {
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strbuf_setlen(&norm, prev_slash - norm.buf + 1);
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skip_add_slash = 1;
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} else {
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strbuf_setlen(&norm, prev_slash - norm.buf);
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}
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}
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url_len -= next_slash - url;
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url = next_slash;
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/* if the next char is not '/' done with the path */
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if (*url != '/')
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break;
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url++;
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url_len--;
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if (!skip_add_slash)
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strbuf_addch(&norm, '/');
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}
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path_len = norm.len - path_off;
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/*
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* Now simply copy the rest, if any, only normalizing %-escapes and
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* being careful not to corrupt the URL by unescaping any delimiters.
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*/
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if (*url) {
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if (!append_normalized_escapes(&norm, url, url_len, "", URL_RESERVED)) {
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if (out_info) {
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out_info->url = NULL;
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out_info->err = _("invalid %XX escape sequence");
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}
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strbuf_release(&norm);
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return NULL;
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}
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}
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result = strbuf_detach(&norm, &result_len);
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if (out_info) {
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out_info->url = result;
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out_info->err = NULL;
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out_info->url_len = result_len;
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out_info->scheme_len = scheme_len;
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out_info->user_off = user_off;
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out_info->user_len = user_len;
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out_info->passwd_off = passwd_off;
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out_info->passwd_len = passwd_len;
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out_info->host_off = host_off;
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out_info->host_len = host_len;
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out_info->port_len = port_len;
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out_info->path_off = path_off;
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out_info->path_len = path_len;
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}
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return result;
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}
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static size_t url_match_prefix(const char *url,
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const char *url_prefix,
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size_t url_prefix_len)
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{
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/*
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* url_prefix matches url if url_prefix is an exact match for url or it
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* is a prefix of url and the match ends on a path component boundary.
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* Both url and url_prefix are considered to have an implicit '/' on the
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* end for matching purposes if they do not already.
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*
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* url must be NUL terminated. url_prefix_len is the length of
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* url_prefix which need not be NUL terminated.
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*
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* The return value is the length of the match in characters (including
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* the final '/' even if it's implicit) or 0 for no match.
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*
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* Passing NULL as url and/or url_prefix will always cause 0 to be
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* returned without causing any faults.
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*/
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if (!url || !url_prefix)
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return 0;
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if (!url_prefix_len || (url_prefix_len == 1 && *url_prefix == '/'))
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return (!*url || *url == '/') ? 1 : 0;
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if (url_prefix[url_prefix_len - 1] == '/')
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url_prefix_len--;
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if (strncmp(url, url_prefix, url_prefix_len))
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return 0;
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if ((strlen(url) == url_prefix_len) || (url[url_prefix_len] == '/'))
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return url_prefix_len + 1;
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return 0;
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}
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int match_urls(const struct url_info *url,
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const struct url_info *url_prefix,
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int *exactusermatch)
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{
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/*
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* url_prefix matches url if the scheme, host and port of url_prefix
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* are the same as those of url and the path portion of url_prefix
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* is the same as the path portion of url or it is a prefix that
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* matches at a '/' boundary. If url_prefix contains a user name,
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* that must also exactly match the user name in url.
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*
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* If the user, host, port and path match in this fashion, the returned
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* value is the length of the path match including any implicit
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* final '/'. For example, "http://me@example.com/path" is matched by
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* "http://example.com" with a path length of 1.
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*
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* If there is a match and exactusermatch is not NULL, then
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* *exactusermatch will be set to true if both url and url_prefix
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* contained a user name or false if url_prefix did not have a
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* user name. If there is no match *exactusermatch is left untouched.
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*/
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int usermatched = 0;
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int pathmatchlen;
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if (!url || !url_prefix || !url->url || !url_prefix->url)
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return 0;
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/* check the scheme */
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if (url_prefix->scheme_len != url->scheme_len ||
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strncmp(url->url, url_prefix->url, url->scheme_len))
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return 0; /* schemes do not match */
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/* check the user name if url_prefix has one */
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if (url_prefix->user_off) {
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if (!url->user_off || url->user_len != url_prefix->user_len ||
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strncmp(url->url + url->user_off,
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url_prefix->url + url_prefix->user_off,
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url->user_len))
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return 0; /* url_prefix has a user but it's not a match */
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usermatched = 1;
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}
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/* check the host and port */
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if (url_prefix->host_len != url->host_len ||
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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;
|
|
}
|