From f1bab6b74d84b972a9e817e5028b8e438bf5e83d Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Thu, 15 Aug 2024 21:29:54 +0200
Subject: kernel: disallow NUL bytes in paths

---
 src/kernel/syscalls.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'src/kernel')

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;
 
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