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,int flags)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 int flags)
24 {
25 struct xfs_da_args args = {
26 .dp = XFS_I(inode),
27 .attr_filter = handler->flags,
28 .name = name,
29 .namelen = strlen(name),
30 .value = value,
31 .valuelen = size,
32 };
33 int error;
34
35 error = xfs_attr_get(&args);
36 if (error)
37 return error;
38 return args.valuelen;
39 }
40
41 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)42 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
43 struct inode *inode, const char *name, const void *value,
44 size_t size, int flags)
45 {
46 struct xfs_da_args args = {
47 .dp = XFS_I(inode),
48 .attr_filter = handler->flags,
49 .attr_flags = flags,
50 .name = name,
51 .namelen = strlen(name),
52 .value = (void *)value,
53 .valuelen = size,
54 };
55 int error;
56
57 error = xfs_attr_set(&args);
58 if (!error && (handler->flags & XFS_ATTR_ROOT))
59 xfs_forget_acl(inode, name);
60 return error;
61 }
62
63 static const struct xattr_handler xfs_xattr_user_handler = {
64 .prefix = XATTR_USER_PREFIX,
65 .flags = 0, /* no flags implies user namespace */
66 .get = xfs_xattr_get,
67 .set = xfs_xattr_set,
68 };
69
70 static const struct xattr_handler xfs_xattr_trusted_handler = {
71 .prefix = XATTR_TRUSTED_PREFIX,
72 .flags = XFS_ATTR_ROOT,
73 .get = xfs_xattr_get,
74 .set = xfs_xattr_set,
75 };
76
77 static const struct xattr_handler xfs_xattr_security_handler = {
78 .prefix = XATTR_SECURITY_PREFIX,
79 .flags = XFS_ATTR_SECURE,
80 .get = xfs_xattr_get,
81 .set = xfs_xattr_set,
82 };
83
84 const struct xattr_handler *xfs_xattr_handlers[] = {
85 &xfs_xattr_user_handler,
86 &xfs_xattr_trusted_handler,
87 &xfs_xattr_security_handler,
88 #ifdef CONFIG_XFS_POSIX_ACL
89 &posix_acl_access_xattr_handler,
90 &posix_acl_default_xattr_handler,
91 #endif
92 NULL
93 };
94
95 static void
__xfs_xattr_put_listent(struct xfs_attr_list_context * context,char * prefix,int prefix_len,unsigned char * name,int namelen)96 __xfs_xattr_put_listent(
97 struct xfs_attr_list_context *context,
98 char *prefix,
99 int prefix_len,
100 unsigned char *name,
101 int namelen)
102 {
103 char *offset;
104 int arraytop;
105
106 if (context->count < 0 || context->seen_enough)
107 return;
108
109 if (!context->buffer)
110 goto compute_size;
111
112 arraytop = context->count + prefix_len + namelen + 1;
113 if (arraytop > context->firstu) {
114 context->count = -1; /* insufficient space */
115 context->seen_enough = 1;
116 return;
117 }
118 offset = context->buffer + context->count;
119 strncpy(offset, prefix, prefix_len);
120 offset += prefix_len;
121 strncpy(offset, (char *)name, namelen); /* real name */
122 offset += namelen;
123 *offset = '\0';
124
125 compute_size:
126 context->count += prefix_len + namelen + 1;
127 return;
128 }
129
130 static void
xfs_xattr_put_listent(struct xfs_attr_list_context * context,int flags,unsigned char * name,int namelen,int valuelen)131 xfs_xattr_put_listent(
132 struct xfs_attr_list_context *context,
133 int flags,
134 unsigned char *name,
135 int namelen,
136 int valuelen)
137 {
138 char *prefix;
139 int prefix_len;
140
141 ASSERT(context->count >= 0);
142
143 if (flags & XFS_ATTR_ROOT) {
144 #ifdef CONFIG_XFS_POSIX_ACL
145 if (namelen == SGI_ACL_FILE_SIZE &&
146 strncmp(name, SGI_ACL_FILE,
147 SGI_ACL_FILE_SIZE) == 0) {
148 __xfs_xattr_put_listent(
149 context, XATTR_SYSTEM_PREFIX,
150 XATTR_SYSTEM_PREFIX_LEN,
151 XATTR_POSIX_ACL_ACCESS,
152 strlen(XATTR_POSIX_ACL_ACCESS));
153 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
154 strncmp(name, SGI_ACL_DEFAULT,
155 SGI_ACL_DEFAULT_SIZE) == 0) {
156 __xfs_xattr_put_listent(
157 context, XATTR_SYSTEM_PREFIX,
158 XATTR_SYSTEM_PREFIX_LEN,
159 XATTR_POSIX_ACL_DEFAULT,
160 strlen(XATTR_POSIX_ACL_DEFAULT));
161 }
162 #endif
163
164 /*
165 * Only show root namespace entries if we are actually allowed to
166 * see them.
167 */
168 if (!capable(CAP_SYS_ADMIN))
169 return;
170
171 prefix = XATTR_TRUSTED_PREFIX;
172 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
173 } else if (flags & XFS_ATTR_SECURE) {
174 prefix = XATTR_SECURITY_PREFIX;
175 prefix_len = XATTR_SECURITY_PREFIX_LEN;
176 } else {
177 prefix = XATTR_USER_PREFIX;
178 prefix_len = XATTR_USER_PREFIX_LEN;
179 }
180
181 __xfs_xattr_put_listent(context, prefix, prefix_len, name,
182 namelen);
183 return;
184 }
185
186 ssize_t
xfs_vn_listxattr(struct dentry * dentry,char * data,size_t size)187 xfs_vn_listxattr(
188 struct dentry *dentry,
189 char *data,
190 size_t size)
191 {
192 struct xfs_attr_list_context context;
193 struct inode *inode = d_inode(dentry);
194 int error;
195
196 /*
197 * First read the regular on-disk attributes.
198 */
199 memset(&context, 0, sizeof(context));
200 context.dp = XFS_I(inode);
201 context.resynch = 1;
202 context.buffer = size ? data : NULL;
203 context.bufsize = size;
204 context.firstu = context.bufsize;
205 context.put_listent = xfs_xattr_put_listent;
206
207 error = xfs_attr_list(&context);
208 if (error)
209 return error;
210 if (context.count < 0)
211 return -ERANGE;
212
213 return context.count;
214 }
215