From 13ad6e695f9ffc7847b3afe3e9cbcea8fb3a443f Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 21 Oct 2020 13:36:35 +0000
Subject: [PATCH] networks: Improve parsing IP addresses

loc_network_new_from_string() seem to have had some unexpected
behaviour for invalid inputs.

The function has been tidied up slightly and returns as soon as
some invalid input was detected.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/network.c      | 52 +++++++++++++++++++++++++++++++---------------
 src/test-network.c |  7 +++++++
 2 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/src/network.c b/src/network.c
index 366caa2..c112a41 100644
--- a/src/network.c
+++ b/src/network.c
@@ -160,9 +160,10 @@ LOC_EXPORT int loc_network_new(struct loc_ctx* ctx, struct loc_network** network
 LOC_EXPORT int loc_network_new_from_string(struct loc_ctx* ctx, struct loc_network** network,
 		const char* address_string) {
 	struct in6_addr first_address;
-	unsigned int prefix = 0;
 	char* prefix_string;
-	int r = 1;
+	int r = -EINVAL;
+
+	DEBUG(ctx, "Attempting to parse network %s\n", address_string);
 
 	// Make a copy of the string to work on it
 	char* buffer = strdup(address_string);
@@ -171,29 +172,46 @@ LOC_EXPORT int loc_network_new_from_string(struct loc_ctx* ctx, struct loc_netwo
 	// Split address and prefix
 	address_string = strsep(&prefix_string, "/");
 
-	// Did we find a prefix?
-	if (prefix_string) {
-		// Convert prefix to integer
-		prefix = strtol(prefix_string, NULL, 10);
+	DEBUG(ctx, "  Split into address = %s, prefix = %s\n", address_string, prefix_string);
 
-		if (prefix) {
-			// Parse the address
-			r = loc_parse_address(ctx, address_string, &first_address);
+	// We need to have a prefix
+	if (!prefix_string) {
+		DEBUG(ctx, "No prefix set\n");
+		goto FAIL;
+	}
 
-			// Map the prefix to IPv6 if needed
-			if (IN6_IS_ADDR_V4MAPPED(&first_address))
-				prefix += 96;
-		}
+	// Convert prefix to integer
+	unsigned int prefix = strtol(prefix_string, NULL, 10);
+
+	// End if the prefix was invalid
+	if (!prefix) {
+		DEBUG(ctx, "The prefix is zero or not a number\n");
+		goto FAIL;
+	}
+
+	// Parse the address
+	r = loc_parse_address(ctx, address_string, &first_address);
+	if (r) {
+		DEBUG(ctx, "The address could not be parsed\n");
+		goto FAIL;
 	}
 
+	// Map the prefix to IPv6 if needed
+	if (IN6_IS_ADDR_V4MAPPED(&first_address))
+		prefix += 96;
+
+FAIL:
 	// Free temporary buffer
 	free(buffer);
 
-	if (r == 0) {
-		r = loc_network_new(ctx, network, &first_address, prefix);
-	}
+	// Exit if the parsing was unsuccessful
+	if (r)
+		return r;
+
+	DEBUG(ctx, "GOT HERE\n");
 
-	return r;
+	// Create a new network
+	return loc_network_new(ctx, network, &first_address, prefix);
 }
 
 LOC_EXPORT struct loc_network* loc_network_ref(struct loc_network* network) {
diff --git a/src/test-network.c b/src/test-network.c
index e908b57..85eca00 100644
--- a/src/test-network.c
+++ b/src/test-network.c
@@ -168,6 +168,13 @@ int main(int argc, char** argv) {
 		exit(EXIT_FAILURE);
 	}
 
+	// Try adding a single address
+	err = loc_writer_add_network(writer, &network, "2001:db8::");
+	if (err != -EINVAL) {
+		fprintf(stderr, "It was possible to add an invalid network (err = %d)\n", err);
+		exit(EXIT_FAILURE);
+	}
+
 	FILE* f = tmpfile();
 	if (!f) {
 		fprintf(stderr, "Could not open file for writing: %s\n", strerror(errno));
-- 
2.39.2