Fix a buf and a portability issue found by Jonathan Frech1.1.4

1)
Fix read of potententially uninitialised memory when reading hostname

This bug could cause the program to enter a loop and eventually die
because it cannot allocate memory.

2)
Instead of using execvpe(3) (non-standard), set environ and call
execvp(3). (This works because asroot does not change PATH.)

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 5 insertions, 3 deletions

diff --git a/asroot.c b/asroot.c
index 193926d..eefb81c 100644
--- a/asroot.c
+++ b/asroot.c
@@ -237,11 +237,11 @@ check_password(void)
 	for (;;) {
 		hostname = realloc(hostname, size *= 2);
 		if (!hostname) {
-			fprintf(stderr, "%s: realloc %zu: %s\n", argv0, size, strerror(errno));
+			fprintf(stderr, "%s: realloc1 %zu: %s\n", argv0, size, strerror(errno));
 		}
 		*hostname = 0;
 		if (!gethostname(hostname, size)) {
-			if (!hostname[size - 2])
+			if (strnlen(hostname, size) < size - 1)
 				break;
 		} else if (errno != ENAMETOOLONG) {
 			fprintf(stderr, "%s: gethostname %zu: %s\n", argv0, size, strerror(errno));
@@ -393,7 +393,9 @@ main(int argc, char *argv[])
 		exit(EXIT_ERROR);
 	}
 
-	execvpe(argv[0], argv, new_environ ? new_environ : environ);
+	if (new_environ)
+		environ = new_environ;
+	execvp(argv[0], argv);
 	fprintf(stderr, "%s: execvpe %s: %s\n", argv0, argv[0], strerror(errno));
 	return errno == ENOENT ? EXIT_NOENT : EXIT_EXEC;
 }