From: Alan Cox <alan@linux.intel.com>
Date: Sat, 24 Sep 2016 13:17:25 +0000 (+0100)
Subject: read/write: error oversized requests
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=afe1c661572c7a6e9d9419a51fe78e58b18ecbf3;p=FUZIX.git

read/write: error oversized requests

We could allow it but it's undefined behaviour in the standard and in some
of our driver code, so force a nice clear error.
---

diff --git a/Kernel/syscall_fs.c b/Kernel/syscall_fs.c
index db58a8cc..b4e07214 100644
--- a/Kernel/syscall_fs.c
+++ b/Kernel/syscall_fs.c
@@ -403,7 +403,12 @@ arg_t _read(void)
 	uint8_t flag;
 
 	if (!nbytes)
-	        return 0;
+		return 0;
+
+	if ((ssize_t)nbytes < 0) {
+		udata.u_error = EINVAL;
+	        return -1;
+	}
 
 	if (!valaddr(buf, nbytes))
 	        return -1;
@@ -466,7 +471,12 @@ arg_t _write(void)
 	uint8_t flag;
 
 	if (!nbytes)
-	        return 0;
+		return 0;
+
+	if ((ssize_t)nbytes < 0) {
+		udata.u_error = EINVAL;
+	        return -1;
+	}
 
 	if (!valaddr(buf, nbytes))
 	        return -1;