From: Alan Cox <alan@linux.intel.com>
Date: Sun, 24 Jul 2016 11:11:36 +0000 (+0100)
Subject: ioctl: do the job right this time I hope
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=7c5ac8b92a2671f6cd8454558284e62f054428eb;p=FUZIX.git

ioctl: do the job right this time I hope

We now have four ioctl classes but don't yet use the write only class
---

diff --git a/Kernel/include/kernel.h b/Kernel/include/kernel.h
index 88173c2d..ef0f878a 100644
--- a/Kernel/include/kernel.h
+++ b/Kernel/include/kernel.h
@@ -588,7 +588,14 @@ struct s_argblk {
 #define SELECT_BEGIN		0x8000
 #define SELECT_END		0x8001
 
-#define IOCTL_SUPER		0x4000	/* superuser needed */
+#define IOCTL_NORMAL		0x0000	/* No special rules */
+#define IOCTL_SUPER		0x4000	/* Superuser needed */
+#define IOCTL_KERNEL		0x8000	/* Kernel side only */
+#define IOCTL_WRONLY		0xC000	/* Write handle needed */
+
+#define IOCTL_CLASS_SUPER	0x40
+#define IOCTL_CLASS_KERNEL	0x80
+#define IOCTL_CLASS_WRONLY	0xC0
 
 /*
  *	Ioctl ranges
diff --git a/Kernel/syscall_fs.c b/Kernel/syscall_fs.c
index 43d13348..10d7c550 100644
--- a/Kernel/syscall_fs.c
+++ b/Kernel/syscall_fs.c
@@ -251,27 +251,29 @@ arg_t _ioctl(void)
 {
 	inoptr ino;
 	uint16_t dev;
+	uint8_t rclass = ((uint8_t)(request >> 8)) & 0xC0;
+	struct oft *oftp;
 
 	if ((ino = getinode(fd)) == NULLINODE)
 		return -1;
 
-	if (!(isdevice(ino))) {
+	oftp = of_tab + udata.u_files[fd];
+
+	if (!(isdevice(ino)) || rclass == IOCTL_CLASS_KERNEL) {
 		udata.u_error = ENOTTY;
 		return -1;
 	}
 
-	if ((request & IOCTL_SUPER) && esuper())
+	if (rclass == IOCTL_CLASS_SUPER && esuper())
 	        return -1;
-
-	if (!(getperm(ino) & OTH_WR)) {
+	if (rclass == IOCTL_CLASS_WRONLY && O_ACCMODE(oftp->o_access) == O_RDONLY) {
 		udata.u_error = EPERM;
 		return -1;
 	}
 
 	dev = ino->c_node.i_addr[0];
 
-	/* top bit of request is reserved for kernel originated magic */
-	return d_ioctl(dev, request & 0x7FFF, data);
+	return d_ioctl(dev, request, data);
 }
 
 #undef fd