ignore retvalue (credit @rd235)

CMakeLists.txt

@@ -6,7 +6,7 @@ project(cado
     LANGUAGES C)
 
 include(GNUInstallDirs)
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -pedantic")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_FORTIFY_SOURCE=2 -O2 -Wall -pedantic")
 
 set(LIBS_REQUIRED cap execs mhash pam pam_misc)
 

src/cado.c

@@ -198,7 +198,10 @@ int main(int argc, char*argv[])
 	grantcap = reqcaps & okcaps;
 
 	/* revert setgid mode */
-	setuid(getuid());
+	if (setuid(getuid()) < 0) {
+		fprintf(stderr,"%s: setuid failure\n",progname);
+		exit(2);
+	}
 
 	/* ask for pam authorization (usually password) if required */
 	if (pam_check_required && pam_check(user_groups[0]) != PAM_SUCCESS) {

src/compute_digest.c

@@ -43,7 +43,12 @@ static ssize_t fcompute_digest(int infd, int outfd, char *ascii_digest) {
 
 	while ((n=read(infd,buf,BUFSIZE)) > 0) {
 		mhash(td, buf, n);
-		if (outfd >= 0) write(outfd, buf, n);
+		if (outfd >= 0) {
+			if (write(outfd, buf, n) < 0) {
+				n = -1;
+				break;
+			}
+		}
 		rv += n;
 	}
 

src/scado.c

@@ -97,12 +97,12 @@ static int editor_garbage_collect(char *path) {
 	if(!(childpid = fork())) {
 		/* Child */
 		if(!fork()) {
-			char c = 0;
 			/* Grandchild */
-			if (close(checkpipe[1]) == 0 && setsid() > 0) 
-				read(checkpipe[0], &c, 1);
-			if (c == 0)
-				unlink(path);
+			if (close(checkpipe[1]) == 0 && setsid() > 0) {
+				char c;
+				if (read(checkpipe[0], &c, 1) == 0)
+					unlink(path);
+			}
 			exit(0);
 		} else
 			exit(0);
@@ -115,7 +115,8 @@ static int editor_garbage_collect(char *path) {
 
 static void editor_garbage_collect_do_not_unlink(int fd) {
 	char c = 'K'; // keep it, any other non-null char would fit.
-	write(fd, &c, 1);
+	int n = write(fd, &c, 1);
+	(void) n;
 }
 
 /* command line selectable functions */
@@ -188,7 +189,7 @@ int scado_edit(char *progname, char *username, char *program_path) {
 	char tmp_file[PATH_MAX];
 	char scado_file[PATH_MAX];
 	char *editor;
-	char *args = NULL;
+	char *args;
 	int status = 0;
 	pid_t pid, xpid;
 	char digest_before[DIGESTSTRLEN + 1];
@@ -242,9 +243,7 @@ int scado_edit(char *progname, char *username, char *program_path) {
 				exit(ERROR_EXIT);
 			}
 
-			asprintf(&args, "%s %s", editor, tmp_file);
-
-			if (args == NULL) {
+			if (asprintf(&args, "%s %s", editor, tmp_file) < 0) {
 				exit(ERROR_EXIT);
 			}