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Commits › 692d9fb
fetch: respect RFC 3986
Baptiste Daroussin committed 21 days ago
commit 692d9fbfcc16c28fbc0c2183f7037cb900808b43
parent 3adfda1
1 file changed +77 -0
modified external/fetch/fetch.c
@@ -328,6 +328,82 @@ fetch_pctdecode(char *dst, const char *src, size_t dlen)
}



/*
+ 
 * Apply RFC 3986 section 5.2.4 "Remove Dot Segments" in place.
+ 
 * Collapses "." and ".." path segments so servers that refuse
+ 
 * non-normalized request targets (e.g. paths containing "/./")
+ 
 * do not reject otherwise valid requests.
+ 
 */
+ 
static void
+ 
fetch_remove_dot_segments(char *path)
+ 
{
+ 
	char *in = path, *out = path;
+
+ 
	while (*in != '\0') {
+ 
		/*
+ 
		 * A. Drop:
+ 
		 *    - leading "../"
+ 
		 *    - leading "./"
+ 
		 */
+ 
		if (strncmp(in, "../", 3) == 0) {
+ 
			in += 3;
+ 
			continue;
+ 
		}
+ 
		if (strncmp(in, "./", 2) == 0) {
+ 
			in += 2;
+ 
			continue;
+ 
		}
+ 
		/*
+ 
		 * B. Replace:
+ 
		 *    - leading "/./" -> "/"
+ 
		 *    - ending "/." -> "/"
+ 
		 */
+ 
		if (strncmp(in, "/./", 3) == 0) {
+ 
			in += 2;
+ 
			continue;
+ 
		}
+ 
		if (in[0] == '/' && in[1] == '.' && in[2] == '\0') {
+ 
			*out++ = '/';
+ 
			break;
+ 
		}
+ 
		/*
+ 
		 * C.
+ 
		 *   - replace leading "/../" -> "/" and remove the last segment
+ 
		 *   - drop the ending "/.." and remove the last segment
+ 
		 */
+ 
		if (strncmp(in, "/../", 4) == 0) {
+ 
			in += 3;
+ 
			while (out > path && *--out != '/')
+ 
				/* remove segment */;
+ 
			continue;
+ 
		}
+ 
		if (in[0] == '/' && in[1] == '.' && in[2] == '.' &&
+ 
		    in[3] == '\0') {
+ 
			in += 3;
+ 
			while (out > path && *--out != '/')
+ 
				/* remove segment */;
+ 
			*out++ = '/';
+ 
			break;
+ 
		}
+ 
		/*
+ 
		 * D. Drop:
+ 
		 *    - bare "."
+ 
		 *    - base ".."
+ 
		 */
+ 
		if ((in[0] == '.' && in[1] == '\0') ||
+ 
		    (in[0] == '.' && in[1] == '.' && in[2] == '\0'))
+ 
			break;
+ 
		/*
+ 
		 * E. now move to th next segment copying to the output.
+ 
		 */
+ 
		if (*in == '/')
+ 
			*out++ = *in++;
+ 
		while (*in != '\0' && *in != '/')
+ 
			*out++ = *in++;
+ 
	}
+ 
	*out = '\0';
+ 
}
+
+ 
/*

 * Split an URL into components. URL syntax is:

 * [method:/][/[user[:pwd]@]host[:port]/][document]

 * This almost, but not quite, RFC1738 URL syntax.
@@ -453,6 +529,7 @@ nohost:
			}

		}

		*doc = '\0';
+ 
		fetch_remove_dot_segments(u->doc);

	} else if ((u->doc = strdup(p)) == NULL) {

		fetch_syserr();

		goto ouch;