[PATCH] Some fixes for compat ioctl

While doing some compat_ioctl conversions I noticed a few issues in
compat_sys_ioctl:

- It is not completely compatible to old ->ioctl because the traditional
  common ioctls are not checked before it.  I added a check for those.  The
  main advantage is that the handler now works the same as a traditional
  handler even when it returns -EINVAL

- The private socket ioctl check should only apply for sockets.

- There was a security hook missing.  Drawback is that it uses the same
  hook now, and the LSM module cannot distingush between 32bit and 64bit
  clients.  But it'll have to live with that for now.
Signed-off-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/compat.c

@@ -25,6 +25,7 @@
 #include <linux/file.h>
 #include <linux/vfs.h>
 #include <linux/ioctl32.h>
+#include <linux/ioctl.h>
 #include <linux/init.h>
 #include <linux/sockios.h>	/* for SIOCDEVPRIVATE */
 #include <linux/smb.h>
@@ -47,6 +48,7 @@
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
+#include <asm/ioctls.h>
 
 /*
  * Not all architectures have sys_utime, so implement this in terms
@@ -437,16 +439,41 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
 	if (!filp)
 		goto out;
 
-	if (filp->f_op && filp->f_op->compat_ioctl) {
-		error = filp->f_op->compat_ioctl(filp, cmd, arg);
-		if (error != -ENOIOCTLCMD)
-			goto out_fput;
-	}
+	/*
+	 * To allow the compat_ioctl handlers to be self contained
+	 * we need to check the common ioctls here first.
+	 * Just handle them with the standard handlers below.
+	 */
+	switch (cmd) {
+	case FIOCLEX:
+	case FIONCLEX:
+	case FIONBIO:
+	case FIOASYNC:
+	case FIOQSIZE:
+		break;
 
-	if (!filp->f_op ||
-	    (!filp->f_op->ioctl && !filp->f_op->unlocked_ioctl))
-		goto do_ioctl;
+	case FIBMAP:
+	case FIGETBSZ:
+	case FIONREAD:
+		if (S_ISREG(filp->f_dentry->d_inode->i_mode))
+			break;
+		/*FALL THROUGH*/
 
+	default:
+		if (filp->f_op && filp->f_op->compat_ioctl) {
+			error = filp->f_op->compat_ioctl(filp, cmd, arg);
+			if (error != -ENOIOCTLCMD)
+				goto out_fput;
+		}
+
+		if (!filp->f_op ||
+		    (!filp->f_op->ioctl && !filp->f_op->unlocked_ioctl))
+			goto do_ioctl;
+		break;
+	}
+
+	/* When register_ioctl32_conversion is finally gone remove
+	   this lock! -AK */
 	down_read(&ioctl32_sem);
 	for (t = ioctl32_hash_table[ioctl32_hash(cmd)]; t; t = t->next) {
 		if (t->cmd == cmd)
@@ -454,7 +481,8 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
 	}
 	up_read(&ioctl32_sem);
 
-	if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {
+	if (S_ISSOCK(filp->f_dentry->d_inode->i_mode) &&
+	    cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {
 		error = siocdevprivate_ioctl(fd, cmd, arg);
 	} else {
 		static int count;
@@ -468,6 +496,11 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
 
  found_handler:
 	if (t->handler) {
+		/* RED-PEN how should LSM module know it's handling 32bit? */
+		error = security_file_ioctl(filp, cmd, arg);
+		if (error)
+			goto out_fput;
+
 		lock_kernel();
 		error = t->handler(fd, cmd, arg, filp);
 		unlock_kernel();

fs/ioctl.c

@@ -78,6 +78,10 @@ static int file_ioctl(struct file *filp, unsigned int cmd,
 }
 
 
+/*
+ * When you add any new common ioctls to the switches above and below
+ * please update compat_sys_ioctl() too.
+ */
 asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 {
 	struct file * filp;