kernel: disallow NUL bytes in paths

1 files changed, 8 insertions, 0 deletions

diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index e94f886..a6c807c 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -73,6 +73,14 @@ hid_t _sys_open(const char __user *path, long len, int flags) {
 		goto fail;
 	}
 
+	/* I used to allow NUL in paths. Now I don't, but I want to keep the same
+	 * API -- so let's reject paths with NUL in them. */
+	for (long i = 0; i < len; i++) {
+		if (path_buf[i] == '\0') {
+			goto fail;
+		}
+	}
+
 	len = path_simplify(path_buf, path_buf, len);
 	if (len == 0) goto fail;