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
15 #include <linux/posix_acl_xattr.h>
16 #include <linux/xattr.h>
17
18
19 static int
xfs_xattr_get(const struct xattr_handler * handler,struct dentry * unused,struct inode * inode,const char * name,void * value,size_t size)20 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
21 struct inode *inode, const char *name, void *value, size_t size)
22 {
23 int xflags = handler->flags;
24 struct xfs_inode *ip = XFS_I(inode);
25 int error, asize = size;
26
27 /* Convert Linux syscall to XFS internal ATTR flags */
28 if (!size) {
29 xflags |= ATTR_KERNOVAL;
30 value = NULL;
31 }
32
33 error = xfs_attr_get(ip, name, (unsigned char **)&value, &asize, xflags);
34 if (error)
35 return error;
36 return asize;
37 }
38
39 void
xfs_forget_acl(struct inode * inode,const char * name,int xflags)40 xfs_forget_acl(
41 struct inode *inode,
42 const char *name,
43 int xflags)
44 {
45 /*
46 * Invalidate any cached ACLs if the user has bypassed the ACL
47 * interface. We don't validate the content whatsoever so it is caller
48 * responsibility to provide data in valid format and ensure i_mode is
49 * consistent.
50 */
51 if (xflags & ATTR_ROOT) {
52 #ifdef CONFIG_XFS_POSIX_ACL
53 if (!strcmp(name, SGI_ACL_FILE))
54 forget_cached_acl(inode, ACL_TYPE_ACCESS);
55 else if (!strcmp(name, SGI_ACL_DEFAULT))
56 forget_cached_acl(inode, ACL_TYPE_DEFAULT);
57 #endif
58 }
59 }
60
61 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)62 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
63 struct inode *inode, const char *name, const void *value,
64 size_t size, int flags)
65 {
66 int xflags = handler->flags;
67 struct xfs_inode *ip = XFS_I(inode);
68 int error;
69
70 /* Convert Linux syscall to XFS internal ATTR flags */
71 if (flags & XATTR_CREATE)
72 xflags |= ATTR_CREATE;
73 if (flags & XATTR_REPLACE)
74 xflags |= ATTR_REPLACE;
75
76 if (!value)
77 return xfs_attr_remove(ip, (unsigned char *)name, xflags);
78 error = xfs_attr_set(ip, (unsigned char *)name,
79 (void *)value, size, xflags);
80 if (!error)
81 xfs_forget_acl(inode, name, xflags);
82
83 return error;
84 }
85
86 static const struct xattr_handler xfs_xattr_user_handler = {
87 .prefix = XATTR_USER_PREFIX,
88 .flags = 0, /* no flags implies user namespace */
89 .get = xfs_xattr_get,
90 .set = xfs_xattr_set,
91 };
92
93 static const struct xattr_handler xfs_xattr_trusted_handler = {
94 .prefix = XATTR_TRUSTED_PREFIX,
95 .flags = ATTR_ROOT,
96 .get = xfs_xattr_get,
97 .set = xfs_xattr_set,
98 };
99
100 static const struct xattr_handler xfs_xattr_security_handler = {
101 .prefix = XATTR_SECURITY_PREFIX,
102 .flags = ATTR_SECURE,
103 .get = xfs_xattr_get,
104 .set = xfs_xattr_set,
105 };
106
107 const struct xattr_handler *xfs_xattr_handlers[] = {
108 &xfs_xattr_user_handler,
109 &xfs_xattr_trusted_handler,
110 &xfs_xattr_security_handler,
111 #ifdef CONFIG_XFS_POSIX_ACL
112 &posix_acl_access_xattr_handler,
113 &posix_acl_default_xattr_handler,
114 #endif
115 NULL
116 };
117
118 static void
__xfs_xattr_put_listent(struct xfs_attr_list_context * context,char * prefix,int prefix_len,unsigned char * name,int namelen)119 __xfs_xattr_put_listent(
120 struct xfs_attr_list_context *context,
121 char *prefix,
122 int prefix_len,
123 unsigned char *name,
124 int namelen)
125 {
126 char *offset;
127 int arraytop;
128
129 if (context->count < 0 || context->seen_enough)
130 return;
131
132 if (!context->alist)
133 goto compute_size;
134
135 arraytop = context->count + prefix_len + namelen + 1;
136 if (arraytop > context->firstu) {
137 context->count = -1; /* insufficient space */
138 context->seen_enough = 1;
139 return;
140 }
141 offset = (char *)context->alist + context->count;
142 strncpy(offset, prefix, prefix_len);
143 offset += prefix_len;
144 strncpy(offset, (char *)name, namelen); /* real name */
145 offset += namelen;
146 *offset = '\0';
147
148 compute_size:
149 context->count += prefix_len + namelen + 1;
150 return;
151 }
152
153 static void
xfs_xattr_put_listent(struct xfs_attr_list_context * context,int flags,unsigned char * name,int namelen,int valuelen)154 xfs_xattr_put_listent(
155 struct xfs_attr_list_context *context,
156 int flags,
157 unsigned char *name,
158 int namelen,
159 int valuelen)
160 {
161 char *prefix;
162 int prefix_len;
163
164 ASSERT(context->count >= 0);
165
166 if (flags & XFS_ATTR_ROOT) {
167 #ifdef CONFIG_XFS_POSIX_ACL
168 if (namelen == SGI_ACL_FILE_SIZE &&
169 strncmp(name, SGI_ACL_FILE,
170 SGI_ACL_FILE_SIZE) == 0) {
171 __xfs_xattr_put_listent(
172 context, XATTR_SYSTEM_PREFIX,
173 XATTR_SYSTEM_PREFIX_LEN,
174 XATTR_POSIX_ACL_ACCESS,
175 strlen(XATTR_POSIX_ACL_ACCESS));
176 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
177 strncmp(name, SGI_ACL_DEFAULT,
178 SGI_ACL_DEFAULT_SIZE) == 0) {
179 __xfs_xattr_put_listent(
180 context, XATTR_SYSTEM_PREFIX,
181 XATTR_SYSTEM_PREFIX_LEN,
182 XATTR_POSIX_ACL_DEFAULT,
183 strlen(XATTR_POSIX_ACL_DEFAULT));
184 }
185 #endif
186
187 /*
188 * Only show root namespace entries if we are actually allowed to
189 * see them.
190 */
191 if (!capable(CAP_SYS_ADMIN))
192 return;
193
194 prefix = XATTR_TRUSTED_PREFIX;
195 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
196 } else if (flags & XFS_ATTR_SECURE) {
197 prefix = XATTR_SECURITY_PREFIX;
198 prefix_len = XATTR_SECURITY_PREFIX_LEN;
199 } else {
200 prefix = XATTR_USER_PREFIX;
201 prefix_len = XATTR_USER_PREFIX_LEN;
202 }
203
204 __xfs_xattr_put_listent(context, prefix, prefix_len, name,
205 namelen);
206 return;
207 }
208
209 ssize_t
xfs_vn_listxattr(struct dentry * dentry,char * data,size_t size)210 xfs_vn_listxattr(
211 struct dentry *dentry,
212 char *data,
213 size_t size)
214 {
215 struct xfs_attr_list_context context;
216 struct attrlist_cursor_kern cursor = { 0 };
217 struct inode *inode = d_inode(dentry);
218 int error;
219
220 /*
221 * First read the regular on-disk attributes.
222 */
223 memset(&context, 0, sizeof(context));
224 context.dp = XFS_I(inode);
225 context.cursor = &cursor;
226 context.resynch = 1;
227 context.alist = size ? data : NULL;
228 context.bufsize = size;
229 context.firstu = context.bufsize;
230 context.put_listent = xfs_xattr_put_listent;
231
232 error = xfs_attr_list_int(&context);
233 if (error)
234 return error;
235 if (context.count < 0)
236 return -ERANGE;
237
238 return context.count;
239 }
240
