xref: /openbmc/qemu/hw/9pfs/9p-xattr-user.c (revision f6476697)
1 /*
2  * 9p user. xattr callback
3  *
4  * Copyright IBM, Corp. 2010
5  *
6  * Authors:
7  * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 #include "9p.h"
16 #include "fsdev/file-op-9p.h"
17 #include "9p-xattr.h"
18 
19 
20 static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
21                                 const char *name, void *value, size_t size)
22 {
23     if (strncmp(name, "user.virtfs.", 12) == 0) {
24         /*
25          * Don't allow fetch of user.virtfs namesapce
26          * in case of mapped security
27          */
28         errno = ENOATTR;
29         return -1;
30     }
31     return local_getxattr_nofollow(ctx, path, name, value, size);
32 }
33 
34 static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
35                                  char *name, void *value, size_t size)
36 {
37     int name_size = strlen(name) + 1;
38     if (strncmp(name, "user.virtfs.", 12) == 0) {
39 
40         /*  check if it is a mapped posix acl */
41         if (strncmp(name, "user.virtfs.system.posix_acl_", 29) == 0) {
42             /* adjust the name and size */
43             name += 12;
44             name_size -= 12;
45         } else {
46             /*
47              * Don't allow fetch of user.virtfs namesapce
48              * in case of mapped security
49              */
50             return 0;
51         }
52     }
53     if (!value) {
54         return name_size;
55     }
56 
57     if (size < name_size) {
58         errno = ERANGE;
59         return -1;
60     }
61 
62     /* name_size includes the trailing NUL. */
63     memcpy(value, name, name_size);
64     return name_size;
65 }
66 
67 static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
68                             void *value, size_t size, int flags)
69 {
70     if (strncmp(name, "user.virtfs.", 12) == 0) {
71         /*
72          * Don't allow fetch of user.virtfs namesapce
73          * in case of mapped security
74          */
75         errno = EACCES;
76         return -1;
77     }
78     return local_setxattr_nofollow(ctx, path, name, value, size, flags);
79 }
80 
81 static int mp_user_removexattr(FsContext *ctx,
82                                const char *path, const char *name)
83 {
84     if (strncmp(name, "user.virtfs.", 12) == 0) {
85         /*
86          * Don't allow fetch of user.virtfs namesapce
87          * in case of mapped security
88          */
89         errno = EACCES;
90         return -1;
91     }
92     return local_removexattr_nofollow(ctx, path, name);
93 }
94 
95 XattrOperations mapped_user_xattr = {
96     .name = "user.",
97     .getxattr = mp_user_getxattr,
98     .setxattr = mp_user_setxattr,
99     .listxattr = mp_user_listxattr,
100     .removexattr = mp_user_removexattr,
101 };
102 
103 XattrOperations passthrough_user_xattr = {
104     .name = "user.",
105     .getxattr = pt_getxattr,
106     .setxattr = pt_setxattr,
107     .listxattr = pt_listxattr,
108     .removexattr = pt_removexattr,
109 };
110