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/*
* Copyright (c) 2021 Matthias Schmidt <xhr@giessen.ccc.de>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <ctype.h>
#include <limits.h>
#include <string.h>
#include "log.h"
#include "twind.h"
char hex_to_int(char);
char* uridecode(const char *);
/*
* The following two functions are from https://geekhideout.com/urlcode.shtml
* and provided without license restrictions
*/
char hex_to_int(char ch) {
return isdigit(ch) ? ch - '0' : tolower(ch) - 'a' + 10;
}
char *
uridecode(const char *request)
{
char *temp = xmalloc(strlen(request) + 1);
const char *p;
char *pt;
p = request;
pt = temp;
while (*p) {
if (*p == '%') {
if (p[1] && p[2]) {
*pt++ = hex_to_int(p[1]) << 4 | hex_to_int(p[2]);
p += 2;
}
} else if (*p == '+') {
*pt++ = ' ';
} else {
*pt++ = *p;
}
p++;
}
*pt = '\0';
return temp;
}
int
get_path_from_request(char *request, char *finalpath)
{
char hostname[MAXREQLEN];
char localpath[MAXREQLEN];
char temp[MAXREQLEN];
char *p, *decoded_request;
int pos = 0, ret;
memset(hostname, 0, sizeof(hostname));
memset(localpath, 0, sizeof(localpath));
memset(temp, 0, sizeof(temp));
p = request;
if ((p = strchr(request, '\r')) == NULL) {
log_info("\\r missing from request, abort processing");
return -1;
}
*p = '\0'; /* Strip \r\n */
p = request;
if (strncmp(p, "gemini://", 9) != 0) {
log_info("Gemini scheme missing, abort processing");
return -1;
}
memmove(request, p + 9, strlen(request) + 1 - 9);
decoded_request = uridecode(request);
/* save hostname */
if ((p = strchr(decoded_request, '/')) != NULL)
snprintf(hostname, strlen(decoded_request) - strlen(p)+1, "%s",
decoded_request);
else
snprintf(hostname, strlen(decoded_request)+1, "%s", decoded_request);
/* Strip possible port (e.g. :1965) from hostname */
if ((p = strrchr(hostname, ':')) != NULL) {
pos = strlen(hostname) - strlen(p);
if (pos < 0 || pos > _POSIX_HOST_NAME_MAX)
fatalx("pos while shorten hostname out of range");
hostname[pos] = '\0';
}
/* Remove ../ for security reasons */
while ((p = strstr(decoded_request, "/..")) != NULL) {
memmove(decoded_request, p + 3, strlen(p) + 1 - 3);
}
if ((p = strchr(decoded_request, '/')) != NULL) {
/* Save all after the first / in localpath */
snprintf(localpath, strlen(decoded_request), "%s", p+1);
if (strlen(localpath) == 0) {
/*
* If the request is 'example.com/', localpart will be empty. In this case
* write the default to it.
*/
sprintf(localpath, "index.gmi");
}
} else {
/* There is no slash in the request, so assume index.gmi */
sprintf(localpath, "index.gmi");
}
/*
*We do not need to take the base dir aka /var/db/gemini into account
* since we already chroot() to _PATH_TWIND_CHROOT .
*
* Here, a string truncation could happen. This can be implemented
* better! XXX FIXME
*/
snprintf(finalpath, MAXREQLEN, "%s/%s", hostname, localpath);
/* Check if the wanted path exists and if it's a directory */
ret = check_gemini_file(finalpath);
if (ret < 0) {
log_debug("%s not found", finalpath);
free(decoded_request);
return -2;
} else if (ret == 1) {
log_debug("%s is a directory", finalpath);
/* Auto append index.gmi if destination is a directory */
snprintf(temp, MAXREQLEN, "%s", finalpath);
snprintf(finalpath, MAXREQLEN, "%s/index.gmi", temp);
}
log_debug("Got request for %s on server %s -> %s",
localpath, hostname, finalpath);
/* decoded_request is no longer used, so it can be freed */
free(decoded_request);
return 0;
}
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