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git/urlmatch.c

618 lines
18 KiB

#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)
return 0;
ch = hex2chr(from);
if (ch < 0)
return 0;
from += 2;
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;
}
static const char *end_of_token(const char *s, int c, size_t n)
{
const char *next = memchr(s, c, n);
if (!next)
next = s + n;
return next;
}
static int match_host(const struct url_info *url_info,
const struct url_info *pattern_info)
{
const char *url = url_info->url + url_info->host_off;
const char *pat = pattern_info->url + pattern_info->host_off;
int url_len = url_info->host_len;
int pat_len = pattern_info->host_len;
while (url_len && pat_len) {
const char *url_next = end_of_token(url, '.', url_len);
const char *pat_next = end_of_token(pat, '.', pat_len);
if (pat_next == pat + 1 && pat[0] == '*')
/* wildcard matches anything */
;
else if ((pat_next - pat) == (url_next - url) &&
!memcmp(url, pat, url_next - url))
/* the components are the same */
;
else
return 0; /* found an unmatch */
if (url_next < url + url_len)
url_next++;
url_len -= url_next - url;
url = url_next;
if (pat_next < pat + pat_len)
pat_next++;
pat_len -= pat_next - pat;
pat = pat_next;
}
return (!url_len && !pat_len);
}
static char *url_normalize_1(const char *url, struct url_info *out_info, char allow_globs)
{
/*
* 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_off=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;
}
if (allow_globs)
spanned = strspn(url, URL_HOST_CHARS "*");
else
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, ':');
port_off = norm.len;
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 - (port_len ? port_len + 1 : 0);
/*
* 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;
size_t seg_start_off = 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;
}
seg_start = norm.buf + seg_start_off;
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_off = port_off;
out_info->port_len = port_len;
out_info->path_off = path_off;
out_info->path_len = path_len;
}
return result;
}
char *url_normalize(const char *url, struct url_info *out_info)
{
return url_normalize_1(url, out_info, 0);
}
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;
}
static int match_urls(const struct url_info *url,
const struct url_info *url_prefix,
struct urlmatch_item *match)
{
/*
* 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.
*/
char usermatched = 0;
size_t 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 */
if (!match_host(url, url_prefix))
return 0; /* host names do not match */
/* check the port */
if (url_prefix->port_len != url->port_len ||
strncmp(url->url + url->port_off,
url_prefix->url + url_prefix->port_off, url->port_len))
return 0; /* 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)
return 0; /* paths do not match */
if (match) {
match->hostmatch_len = url_prefix->host_len;
match->pathmatch_len = pathmatchlen;
match->user_matched = usermatched;
}
return 1;
}
static int cmp_matches(const struct urlmatch_item *a,
const struct urlmatch_item *b)
{
if (a->hostmatch_len != b->hostmatch_len)
return a->hostmatch_len < b->hostmatch_len ? -1 : 1;
if (a->pathmatch_len != b->pathmatch_len)
return a->pathmatch_len < b->pathmatch_len ? -1 : 1;
if (a->user_matched != b->user_matched)
return b->user_matched ? -1 : 1;
return 0;
}
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 = {0};
struct url_info *url = &collect->url;
const char *key, *dot;
struct strbuf synthkey = STRBUF_INIT;
int retval;
int (*select_fn)(const struct urlmatch_item *a, const struct urlmatch_item *b) =
collect->select_fn ? collect->select_fn : cmp_matches;
if (!skip_prefix(var, collect->section, &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_1(config_url, &norm_info, 1);
if (norm_url)
retval = match_urls(url, &norm_info, &matched);
else if (collect->fallback_match_fn)
retval = collect->fallback_match_fn(config_url,
collect->cb);
else
retval = 0;
free(config_url);
free(norm_url);
if (!retval)
return 0;
key = dot + 1;
}
if (collect->key && strcmp(key, collect->key))
return 0;
item = string_list_insert(&collect->vars, key);
if (!item->util) {
item->util = xcalloc(1, sizeof(matched));
} else {
if (select_fn(&matched, item->util) < 0)
/*
* Our match is worse than the old one,
* we cannot use it.
*/
return 0;
/* Otherwise, replace it with this one. */
}
memcpy(item->util, &matched, sizeof(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;
}
void urlmatch_config_release(struct urlmatch_config *config)
{
string_list_clear(&config->vars, 1);
}