1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2008 Christoph Hellwig.
4 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
5 */
6
7 #include "xfs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_da_format.h"
12 #include "xfs_inode.h"
13 #include "xfs_attr.h"
14 #include "xfs_acl.h"
15 #include "xfs_da_btree.h"
16
17 #include <linux/posix_acl_xattr.h>
18
19
20 static int
xfs_xattr_get(const struct xattr_handler * handler,struct dentry * unused,struct inode * inode,const char * name,void * value,size_t size)21 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
22 struct inode *inode, const char *name, void *value, size_t size)
23 {
24 struct xfs_da_args args = {
25 .dp = XFS_I(inode),
26 .attr_filter = handler->flags,
27 .name = name,
28 .namelen = strlen(name),
29 .value = value,
30 .valuelen = size,
31 };
32 int error;
33
34 error = xfs_attr_get(&args);
35 if (error)
36 return error;
37 return args.valuelen;
38 }
39
40 static int
xfs_xattr_set(const struct xattr_handler * handler,struct dentry * unused,struct inode * inode,const char * name,const void * value,size_t size,int flags)41 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
42 struct inode *inode, const char *name, const void *value,
43 size_t size, int flags)
44 {
45 struct xfs_da_args args = {
46 .dp = XFS_I(inode),
47 .attr_filter = handler->flags,
48 .attr_flags = flags,
49 .name = name,
50 .namelen = strlen(name),
51 .value = (void *)value,
52 .valuelen = size,
53 };
54 int error;
55
56 error = xfs_attr_set(&args);
57 if (!error && (handler->flags & XFS_ATTR_ROOT))
58 xfs_forget_acl(inode, name);
59 return error;
60 }
61
62 static const struct xattr_handler xfs_xattr_user_handler = {
63 .prefix = XATTR_USER_PREFIX,
64 .flags = 0, /* no flags implies user namespace */
65 .get = xfs_xattr_get,
66 .set = xfs_xattr_set,
67 };
68
69 static const struct xattr_handler xfs_xattr_trusted_handler = {
70 .prefix = XATTR_TRUSTED_PREFIX,
71 .flags = XFS_ATTR_ROOT,
72 .get = xfs_xattr_get,
73 .set = xfs_xattr_set,
74 };
75
76 static const struct xattr_handler xfs_xattr_security_handler = {
77 .prefix = XATTR_SECURITY_PREFIX,
78 .flags = XFS_ATTR_SECURE,
79 .get = xfs_xattr_get,
80 .set = xfs_xattr_set,
81 };
82
83 const struct xattr_handler *xfs_xattr_handlers[] = {
84 &xfs_xattr_user_handler,
85 &xfs_xattr_trusted_handler,
86 &xfs_xattr_security_handler,
87 #ifdef CONFIG_XFS_POSIX_ACL
88 &posix_acl_access_xattr_handler,
89 &posix_acl_default_xattr_handler,
90 #endif
91 NULL
92 };
93
94 static void
__xfs_xattr_put_listent(struct xfs_attr_list_context * context,char * prefix,int prefix_len,unsigned char * name,int namelen)95 __xfs_xattr_put_listent(
96 struct xfs_attr_list_context *context,
97 char *prefix,
98 int prefix_len,
99 unsigned char *name,
100 int namelen)
101 {
102 char *offset;
103 int arraytop;
104
105 if (context->count < 0 || context->seen_enough)
106 return;
107
108 if (!context->buffer)
109 goto compute_size;
110
111 arraytop = context->count + prefix_len + namelen + 1;
112 if (arraytop > context->firstu) {
113 context->count = -1; /* insufficient space */
114 context->seen_enough = 1;
115 return;
116 }
117 offset = context->buffer + context->count;
118 strncpy(offset, prefix, prefix_len);
119 offset += prefix_len;
120 strncpy(offset, (char *)name, namelen); /* real name */
121 offset += namelen;
122 *offset = '\0';
123
124 compute_size:
125 context->count += prefix_len + namelen + 1;
126 return;
127 }
128
129 static void
xfs_xattr_put_listent(struct xfs_attr_list_context * context,int flags,unsigned char * name,int namelen,int valuelen)130 xfs_xattr_put_listent(
131 struct xfs_attr_list_context *context,
132 int flags,
133 unsigned char *name,
134 int namelen,
135 int valuelen)
136 {
137 char *prefix;
138 int prefix_len;
139
140 ASSERT(context->count >= 0);
141
142 if (flags & XFS_ATTR_ROOT) {
143 #ifdef CONFIG_XFS_POSIX_ACL
144 if (namelen == SGI_ACL_FILE_SIZE &&
145 strncmp(name, SGI_ACL_FILE,
146 SGI_ACL_FILE_SIZE) == 0) {
147 __xfs_xattr_put_listent(
148 context, XATTR_SYSTEM_PREFIX,
149 XATTR_SYSTEM_PREFIX_LEN,
150 XATTR_POSIX_ACL_ACCESS,
151 strlen(XATTR_POSIX_ACL_ACCESS));
152 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
153 strncmp(name, SGI_ACL_DEFAULT,
154 SGI_ACL_DEFAULT_SIZE) == 0) {
155 __xfs_xattr_put_listent(
156 context, XATTR_SYSTEM_PREFIX,
157 XATTR_SYSTEM_PREFIX_LEN,
158 XATTR_POSIX_ACL_DEFAULT,
159 strlen(XATTR_POSIX_ACL_DEFAULT));
160 }
161 #endif
162
163 /*
164 * Only show root namespace entries if we are actually allowed to
165 * see them.
166 */
167 if (!capable(CAP_SYS_ADMIN))
168 return;
169
170 prefix = XATTR_TRUSTED_PREFIX;
171 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
172 } else if (flags & XFS_ATTR_SECURE) {
173 prefix = XATTR_SECURITY_PREFIX;
174 prefix_len = XATTR_SECURITY_PREFIX_LEN;
175 } else {
176 prefix = XATTR_USER_PREFIX;
177 prefix_len = XATTR_USER_PREFIX_LEN;
178 }
179
180 __xfs_xattr_put_listent(context, prefix, prefix_len, name,
181 namelen);
182 return;
183 }
184
185 ssize_t
xfs_vn_listxattr(struct dentry * dentry,char * data,size_t size)186 xfs_vn_listxattr(
187 struct dentry *dentry,
188 char *data,
189 size_t size)
190 {
191 struct xfs_attr_list_context context;
192 struct inode *inode = d_inode(dentry);
193 int error;
194
195 /*
196 * First read the regular on-disk attributes.
197 */
198 memset(&context, 0, sizeof(context));
199 context.dp = XFS_I(inode);
200 context.resynch = 1;
201 context.buffer = size ? data : NULL;
202 context.bufsize = size;
203 context.firstu = context.bufsize;
204 context.put_listent = xfs_xattr_put_listent;
205
206 error = xfs_attr_list(&context);
207 if (error)
208 return error;
209 if (context.count < 0)
210 return -ERANGE;
211
212 return context.count;
213 }
214