Merge branch 'dev'

.travis.yml

@@ -0,0 +1,16 @@
+addons:
+   apt:
+      update: true
+      packages:
+         - libnetfilter-queue-dev
+dist: xenial
+language: c
+compiler:
+   - clang
+   - gcc
+before_script:
+   - mkdir build
+script:
+   - cd build
+   - cmake ..
+   - make -j2

CHANGELOG.md

@@ -6,6 +6,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## 0.5.3 - 2019-08-06
+### Fixed
+- Fix two format arguments in debug output printing (fairly pedantic; not even
+  caught by clang analyser).
+- Limit DHCP options to 255 bytes (not 256).
+- Exit if a DHCP option is too long.
+
 ## 0.5.2 - 2019-05-09
 ### Added
 - Add example output "screenshot" to README.

CMakeLists.txt

@@ -18,7 +18,7 @@ endif()
 
 project(
 	${PROJECT}
-	VERSION 0.5.2
+	VERSION 0.5.3
 	DESCRIPTION "DHCP option injector"
 	LANGUAGES C
 	)

README.md

@@ -1,4 +1,5 @@
 # DHCP option injector
+[![Build Status](https://travis-ci.org/misje/dhcpoptinj.svg?branch=dev)](https://travis-ci.org/misje/dhcpoptinj) [![Total alerts](https://img.shields.io/lgtm/alerts/g/misje/dhcpoptinj.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/misje/dhcpoptinj/alerts/)
 
 Have you ever wanted to intercept DHCP requests and squeeze in a few extra DHCP
 options, unbeknownst to the sender? Probably not. However, should the need ever
@@ -104,13 +105,13 @@ Sending mangled packet
 ```
 
 ## Installing
+[![Packaging status](https://repology.org/badge/vertical-allrepos/dhcpoptinj.svg)](https://repology.org/project/dhcpoptinj/versions)
 
-dhcpoptinj is submitted to Debian and will hopefully make it to unstable (and
-consequently testing and stable) in not too long. The deb package is under
-source control at [salsa](https://salsa.debian.org/misje-guest/dhcpoptinj).
-Installing dhcpoptinj from the deb package is recommended over the following
-manual installation procedure, because it also includes a man page, bash
-completion rules, example files etc. 
+dhcpoptinj is in Debian/Ubuntu. The deb package is under source control at
+[salsa](https://salsa.debian.org/misje-guest/dhcpoptinj). Installing
+dhcpoptinj from the deb package is recommended over the following manual
+installation procedure, because it also includes a man page, bash completion
+rules, example files etc. 
 
 ### Prerequisites
 

src/config.c

@@ -317,7 +317,7 @@ static void printHelp(void)
 			"The option hex string is written as a series of two-digit pairs,\n"
 			"optionally delimited by one or more non-hexadecimal characters:\n"
 			"'466A6173','46 6A 61 73', '46:6A:61:73' etc. There is a maximum limit\n"
-			"of 256 bytes per option, excluding the option code (the first byte)\n"
+			"of 255 bytes per option, excluding the option code (the first byte)\n"
 			"and the automatically inserted length byte. At least one option must\n"
 			"be provided.\n"
 			"\n"
@@ -371,8 +371,8 @@ static void addDHCPOption(struct DHCPOptList *list, const char *string)
 	if (!string)
 		return;
 
-	/* Make room for length byte and payload */
-	uint8_t buffer[1 + 256];
+	/* Make room for option code byte and payload */
+	uint8_t buffer[1 + UINT8_MAX];
 	size_t length = 0;
 	for (size_t i = 0; i < strlen(string) && length < sizeof(buffer);)
 	{
@@ -384,8 +384,15 @@ static void addDHCPOption(struct DHCPOptList *list, const char *string)
 		else
 			++i;
 	}
+	/* Will not happen; the cmd.line parsing code expects an argument: */
 	if (!length)
 		return;
+	if (length > UINT8_MAX)
+	{
+		fprintf(stderr, "DHCP option size exceeds the limit of %u bytes\n",
+				UINT8_MAX);
+		exit(EXIT_FAILURE);
+	}
 
 	uint16_t optCode = buffer[0];
 
@@ -522,6 +529,7 @@ static void parseOption(struct Config *config, int option, char *arg, enum Sourc
 					fputs("Could not allocate space for PID file name\n", stderr);
 					exit(EXIT_FAILURE);
 				}
+				// NOLINTNEXTLINE(clang-analyzer-security.insecureAPI.strcpy)
 				strcpy(config->pidFile, src);
 			}
 			break;

src/dhcpoptinj.c

@@ -500,6 +500,7 @@ static void logMessage(int priority, const char *format, ...)
 		if (priority == LOG_NOTICE || priority == LOG_INFO || priority == LOG_DEBUG)
 			f = stdout;
 
+		/* NOLINTNEXTLINE(clang-analyzer-valist.Uninitialized) */
 		vfprintf(f, format, args1);
 	}
 	va_end(args1);
@@ -586,7 +587,7 @@ static void debugLogOptions(void)
 	if (!config->debug)
 		return;
 
-	logMessage(LOG_DEBUG, "%u DHCP option(s) to inject (with a total of %zu bytes): ",
+	logMessage(LOG_DEBUG, "%zu DHCP option(s) to inject (with a total of %zu bytes): ",
 			config->dhcpOptCodeCount, config->dhcpOptsSize);
 
 	for (size_t i = 0; i < config->dhcpOptCodeCount; ++i)
@@ -654,9 +655,9 @@ static void debugLogOptionFound(const struct DHCPOption *option)
 
 static void debugLogOption(const char *action, const struct DHCPOption *option)
 {
-	/* String buffer for hex string (maximum DHCP option length (256) times
+	/* String buffer for hex string (maximum DHCP option length (255) times
 	 * three characters (two digits and a space)) */
-	char optPayload[256 * 3];
+	char optPayload[UINT8_MAX * 3];
 	size_t i = 0;
 	for (; i < option->length; ++i)
 		sprintf(optPayload + 3*i, "%02X ", option->data[i]);
@@ -673,7 +674,7 @@ static void debugLogOption(const char *action, const struct DHCPOption *option)
 			option->code,
 			option->code,
 			optName,
-			optNameLen > alignedWidth ? 0 : alignedWidth - optNameLen,
+			(int)(optNameLen > alignedWidth ? 0 : alignedWidth - optNameLen),
 			"",
 			option->length,
 			optPayload);

src/options.c

@@ -28,7 +28,7 @@ struct DHCPOpt
 {
 	uint8_t code;
 	uint8_t length;
-	uint8_t data[256];
+	uint8_t data[UINT8_MAX];
 };
 
 struct DHCPOptList