Re: [PATCH 1/5] compat_ioctl call seems to miss a security hook

[Chris Wright]

* Michael S. Tsirkin (mst@xxxxxxxxxxxxxx) wrote:
> diff -rup linux-2.6.10-orig/fs/compat.c linux-2.6.10-ioctl-sym/fs/compat.c
> --- linux-2.6.10-orig/fs/compat.c	2005-01-18 10:58:33.609880024 +0200
> +++ linux-2.6.10-ioctl-sym/fs/compat.c	2005-01-18 10:54:26.289478440 +0200
> @@ -437,6 +437,11 @@ asmlinkage long compat_sys_ioctl(unsigne
>  	if (!filp)
>  		goto out;
>  
> +	/* RED-PEN how should LSM module know it's handling 32bit? */
> +	error = security_file_ioctl(filp, cmd, arg);
> + 	if (error)
> + 		goto out_fput;
> +

This is now called twice in the plain do_ioctl: case.  A generic vfs handler
could alleviate that.

===== fs/ioctl.c 1.15 vs edited =====
--- 1.15/fs/ioctl.c	2005-01-15 14:31:01 -08:00
+++ edited/fs/ioctl.c	2005-01-18 11:18:33 -08:00
@@ -77,21 +77,10 @@ static int file_ioctl(struct file *filp,
 	return do_ioctl(filp, cmd, arg);
 }
 
-
-asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
+int vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg)
 {
-	struct file * filp;
 	unsigned int flag;
-	int on, error = -EBADF;
-	int fput_needed;
-
-	filp = fget_light(fd, &fput_needed);
-	if (!filp)
-		goto out;
-
-	error = security_file_ioctl(filp, cmd, arg);
-	if (error)
-		goto out_fput;
+	int on, error = 0;
 
 	switch (cmd) {
 		case FIOCLEX:
@@ -157,6 +146,24 @@ asmlinkage long sys_ioctl(unsigned int f
 				error = do_ioctl(filp, cmd, arg);
 			break;
 	}
+	return error;
+}
+
+asmlinkage long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
+{
+	struct file * filp;
+	int error = -EBADF;
+	int fput_needed;
+
+	filp = fget_light(fd, &fput_needed);
+	if (!filp)
+		goto out;
+
+	error = security_file_ioctl(filp, cmd, arg);
+	if (error)
+		goto out_fput;
+
+	error = vfs_ioctl(filp, fd, cmd, arg);
  out_fput:
 	fput_light(filp, fput_needed);
  out:
===== fs/compat.c 1.48 vs edited =====
--- 1.48/fs/compat.c	2005-01-15 14:31:01 -08:00
+++ edited/fs/compat.c	2005-01-18 11:07:56 -08:00
@@ -437,6 +437,11 @@ asmlinkage long compat_sys_ioctl(unsigne
 	if (!filp)
 		goto out;
 
+	/* RED-PEN how should LSM module know it's handling 32bit? */
+	error = security_file_ioctl(filp, cmd, arg);
+	if (error)
+		goto out_fput;
+
 	if (filp->f_op && filp->f_op->compat_ioctl) {
 		error = filp->f_op->compat_ioctl(filp, cmd, arg);
 		if (error != -ENOIOCTLCMD)
@@ -477,7 +482,7 @@ asmlinkage long compat_sys_ioctl(unsigne
 
 	up_read(&ioctl32_sem);
  do_ioctl:
-	error = sys_ioctl(fd, cmd, arg);
+	error = vfs_ioctl(filp, fd, cmd, arg);
  out_fput:
 	fput_light(filp, fput_needed);
  out:
===== include/linux/fs.h 1.373 vs edited =====
--- 1.373/include/linux/fs.h	2005-01-15 14:31:01 -08:00
+++ edited/include/linux/fs.h	2005-01-18 11:10:54 -08:00
@@ -1564,6 +1564,8 @@ extern int vfs_stat(char __user *, struc
 extern int vfs_lstat(char __user *, struct kstat *);
 extern int vfs_fstat(unsigned int, struct kstat *);
 
+extern int vfs_ioctl(struct file *, unsigned int, unsigned int, unsigned long);
+
 extern struct file_system_type *get_fs_type(const char *name);
 extern struct super_block *get_super(struct block_device *);
 extern struct super_block *user_get_super(dev_t);
-
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