Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check
[linux-2.6.git] / fs / ext2 / ioctl.c
1 /*
2  * linux/fs/ext2/ioctl.c
3  *
4  * Copyright (C) 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  */
9
10 #include "ext2.h"
11 #include <linux/capability.h>
12 #include <linux/time.h>
13 #include <linux/sched.h>
14 #include <linux/compat.h>
15 #include <linux/smp_lock.h>
16 #include <asm/current.h>
17 #include <asm/uaccess.h>
18
19
20 int ext2_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
21                 unsigned long arg)
22 {
23         struct ext2_inode_info *ei = EXT2_I(inode);
24         unsigned int flags;
25
26         ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
27
28         switch (cmd) {
29         case EXT2_IOC_GETFLAGS:
30                 ext2_get_inode_flags(ei);
31                 flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
32                 return put_user(flags, (int __user *) arg);
33         case EXT2_IOC_SETFLAGS: {
34                 unsigned int oldflags;
35
36                 if (IS_RDONLY(inode))
37                         return -EROFS;
38
39                 if (!is_owner_or_cap(inode))
40                         return -EACCES;
41
42                 if (get_user(flags, (int __user *) arg))
43                         return -EFAULT;
44
45                 if (!S_ISDIR(inode->i_mode))
46                         flags &= ~EXT2_DIRSYNC_FL;
47
48                 mutex_lock(&inode->i_mutex);
49                 oldflags = ei->i_flags;
50
51                 /*
52                  * The IMMUTABLE and APPEND_ONLY flags can only be changed by
53                  * the relevant capability.
54                  *
55                  * This test looks nicer. Thanks to Pauline Middelink
56                  */
57                 if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
58                         if (!capable(CAP_LINUX_IMMUTABLE)) {
59                                 mutex_unlock(&inode->i_mutex);
60                                 return -EPERM;
61                         }
62                 }
63
64                 flags = flags & EXT2_FL_USER_MODIFIABLE;
65                 flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
66                 ei->i_flags = flags;
67                 mutex_unlock(&inode->i_mutex);
68
69                 ext2_set_inode_flags(inode);
70                 inode->i_ctime = CURRENT_TIME_SEC;
71                 mark_inode_dirty(inode);
72                 return 0;
73         }
74         case EXT2_IOC_GETVERSION:
75                 return put_user(inode->i_generation, (int __user *) arg);
76         case EXT2_IOC_SETVERSION:
77                 if (!is_owner_or_cap(inode))
78                         return -EPERM;
79                 if (IS_RDONLY(inode))
80                         return -EROFS;
81                 if (get_user(inode->i_generation, (int __user *) arg))
82                         return -EFAULT; 
83                 inode->i_ctime = CURRENT_TIME_SEC;
84                 mark_inode_dirty(inode);
85                 return 0;
86         default:
87                 return -ENOTTY;
88         }
89 }
90
91 #ifdef CONFIG_COMPAT
92 long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
93 {
94         struct inode *inode = file->f_path.dentry->d_inode;
95         int ret;
96
97         /* These are just misnamed, they actually get/put from/to user an int */
98         switch (cmd) {
99         case EXT2_IOC32_GETFLAGS:
100                 cmd = EXT2_IOC_GETFLAGS;
101                 break;
102         case EXT2_IOC32_SETFLAGS:
103                 cmd = EXT2_IOC_SETFLAGS;
104                 break;
105         case EXT2_IOC32_GETVERSION:
106                 cmd = EXT2_IOC_GETVERSION;
107                 break;
108         case EXT2_IOC32_SETVERSION:
109                 cmd = EXT2_IOC_SETVERSION;
110                 break;
111         default:
112                 return -ENOIOCTLCMD;
113         }
114         lock_kernel();
115         ret = ext2_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
116         unlock_kernel();
117         return ret;
118 }
119 #endif