[patch 02/11] Fix the compat XFS_IOC_FSGEOMETRY_V1 ioctl

[sandeen@sandeen.net]

[-- Attachment #1: fix_compat_fsgeometry_v1 --]
[-- Type: text/plain, Size: 2178 bytes --]

This ioctl copies kernel data to the user, so we
must have a compat helper to copy it out to the
32-bit structure; the current code had it backward,
and translated the 32-bit arg to 64-bit, and called
the native ioctl, which copied it back as if it were
talking to 64-bit userspace.  Because the 64-bit arg
has padding on the end on intel, I think this risked
corruption in userspace..

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
--

Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_ioctl32.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_ioctl32.c
+++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_ioctl32.c
@@ -44,6 +44,7 @@
 #include "xfs_error.h"
 #include "xfs_dfrag.h"
 #include "xfs_vnodeops.h"
+#include "xfs_fsops.h"
 #include "xfs_ioctl32.h"
 
 #define  _NATIVE_IOC(cmd, type) \
@@ -68,15 +69,22 @@ xfs_ioctl32_flock_copyin(unsigned long a
 	return (unsigned long)p;
 }
 
-STATIC unsigned long
-xfs_ioctl32_geom_v1_copyin(unsigned long arg)
+/* This handles a copy-out, where the 32-bit user struct lacks padding */
+STATIC int
+xfs_ioc_fsgeometry_v1_compat(
+	xfs_mount_t		*mp,
+	void			__user *arg)
 {
-	compat_xfs_fsop_geom_v1_t __user *p32 = (void __user *)arg;
-	xfs_fsop_geom_v1_t __user *p = compat_alloc_user_space(sizeof(*p));
+	xfs_fsop_geom_v1_t	fsgeo;
+	int			error;
 
-	if (copy_in_user(p, p32, sizeof(*p32)))
+	error = xfs_fs_geometry(mp, (xfs_fsop_geom_t *)&fsgeo, 3);
+	if (error)
+		return -error;
+
+	if (copy_to_user(arg, &fsgeo, sizeof(struct compat_xfs_fsop_geom_v1)))
 		return -XFS_ERROR(EFAULT);
-	return (unsigned long)p;
+	return 0;
 }
 
 STATIC int
@@ -300,9 +308,8 @@ xfs_compat_ioctl(
 		cmd = _NATIVE_IOC(cmd, struct xfs_flock64);
 		break;
 	case XFS_IOC_FSGEOMETRY_V1_32:
-		arg = xfs_ioctl32_geom_v1_copyin(arg);
-		cmd = _NATIVE_IOC(cmd, struct xfs_fsop_geom_v1);
-		break;
+		return xfs_ioc_fsgeometry_v1_compat(XFS_I(inode)->i_mount,
+						    (void __user*)arg);
 
 #else /* These are handled fine if no alignment issues */
 	case XFS_IOC_ALLOCSP:

-- 

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