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_format.h"
9 #include "xfs_log_format.h"
10 #include "xfs_trans_resv.h"
11 #include "xfs_mount.h"
12 #include "xfs_da_format.h"
13 #include "xfs_inode.h"
14 #include "xfs_attr.h"
15 #include "xfs_attr_leaf.h"
16 #include "xfs_acl.h"
17
18 #include <linux/posix_acl_xattr.h>
19 #include <linux/xattr.h>
20
21
22 static int
xfs_xattr_get(const struct xattr_handler * handler,struct dentry * unused,struct inode * inode,const char * name,void * value,size_t size)23 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
24 struct inode *inode, const char *name, void *value, size_t size)
25 {
26 int xflags = handler->flags;
27 struct xfs_inode *ip = XFS_I(inode);
28 int error, asize = size;
29
30 /* Convert Linux syscall to XFS internal ATTR flags */
31 if (!size) {
32 xflags |= ATTR_KERNOVAL;
33 value = NULL;
34 }
35
36 error = xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags);
37 if (error)
38 return error;
39 return asize;
40 }
41
42 void
xfs_forget_acl(struct inode * inode,const char * name,int xflags)43 xfs_forget_acl(
44 struct inode *inode,
45 const char *name,
46 int xflags)
47 {
48 /*
49 * Invalidate any cached ACLs if the user has bypassed the ACL
50 * interface. We don't validate the content whatsoever so it is caller
51 * responsibility to provide data in valid format and ensure i_mode is
52 * consistent.
53 */
54 if (xflags & ATTR_ROOT) {
55 #ifdef CONFIG_XFS_POSIX_ACL
56 if (!strcmp(name, SGI_ACL_FILE))
57 forget_cached_acl(inode, ACL_TYPE_ACCESS);
58 else if (!strcmp(name, SGI_ACL_DEFAULT))
59 forget_cached_acl(inode, ACL_TYPE_DEFAULT);
60 #endif
61 }
62 }
63
64 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)65 xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
66 struct inode *inode, const char *name, const void *value,
67 size_t size, int flags)
68 {
69 int xflags = handler->flags;
70 struct xfs_inode *ip = XFS_I(inode);
71 int error;
72
73 /* Convert Linux syscall to XFS internal ATTR flags */
74 if (flags & XATTR_CREATE)
75 xflags |= ATTR_CREATE;
76 if (flags & XATTR_REPLACE)
77 xflags |= ATTR_REPLACE;
78
79 if (!value)
80 return xfs_attr_remove(ip, (unsigned char *)name, xflags);
81 error = xfs_attr_set(ip, (unsigned char *)name,
82 (void *)value, size, xflags);
83 if (!error)
84 xfs_forget_acl(inode, name, xflags);
85
86 return error;
87 }
88
89 static const struct xattr_handler xfs_xattr_user_handler = {
90 .prefix = XATTR_USER_PREFIX,
91 .flags = 0, /* no flags implies user namespace */
92 .get = xfs_xattr_get,
93 .set = xfs_xattr_set,
94 };
95
96 static const struct xattr_handler xfs_xattr_trusted_handler = {
97 .prefix = XATTR_TRUSTED_PREFIX,
98 .flags = ATTR_ROOT,
99 .get = xfs_xattr_get,
100 .set = xfs_xattr_set,
101 };
102
103 static const struct xattr_handler xfs_xattr_security_handler = {
104 .prefix = XATTR_SECURITY_PREFIX,
105 .flags = ATTR_SECURE,
106 .get = xfs_xattr_get,
107 .set = xfs_xattr_set,
108 };
109
110 const struct xattr_handler *xfs_xattr_handlers[] = {
111 &xfs_xattr_user_handler,
112 &xfs_xattr_trusted_handler,
113 &xfs_xattr_security_handler,
114 #ifdef CONFIG_XFS_POSIX_ACL
115 &posix_acl_access_xattr_handler,
116 &posix_acl_default_xattr_handler,
117 #endif
118 NULL
119 };
120
121 static void
__xfs_xattr_put_listent(struct xfs_attr_list_context * context,char * prefix,int prefix_len,unsigned char * name,int namelen)122 __xfs_xattr_put_listent(
123 struct xfs_attr_list_context *context,
124 char *prefix,
125 int prefix_len,
126 unsigned char *name,
127 int namelen)
128 {
129 char *offset;
130 int arraytop;
131
132 if (context->count < 0 || context->seen_enough)
133 return;
134
135 if (!context->alist)
136 goto compute_size;
137
138 arraytop = context->count + prefix_len + namelen + 1;
139 if (arraytop > context->firstu) {
140 context->count = -1; /* insufficient space */
141 context->seen_enough = 1;
142 return;
143 }
144 offset = (char *)context->alist + context->count;
145 strncpy(offset, prefix, prefix_len);
146 offset += prefix_len;
147 strncpy(offset, (char *)name, namelen); /* real name */
148 offset += namelen;
149 *offset = '\0';
150
151 compute_size:
152 context->count += prefix_len + namelen + 1;
153 return;
154 }
155
156 static void
xfs_xattr_put_listent(struct xfs_attr_list_context * context,int flags,unsigned char * name,int namelen,int valuelen)157 xfs_xattr_put_listent(
158 struct xfs_attr_list_context *context,
159 int flags,
160 unsigned char *name,
161 int namelen,
162 int valuelen)
163 {
164 char *prefix;
165 int prefix_len;
166
167 ASSERT(context->count >= 0);
168
169 if (flags & XFS_ATTR_ROOT) {
170 #ifdef CONFIG_XFS_POSIX_ACL
171 if (namelen == SGI_ACL_FILE_SIZE &&
172 strncmp(name, SGI_ACL_FILE,
173 SGI_ACL_FILE_SIZE) == 0) {
174 __xfs_xattr_put_listent(
175 context, XATTR_SYSTEM_PREFIX,
176 XATTR_SYSTEM_PREFIX_LEN,
177 XATTR_POSIX_ACL_ACCESS,
178 strlen(XATTR_POSIX_ACL_ACCESS));
179 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
180 strncmp(name, SGI_ACL_DEFAULT,
181 SGI_ACL_DEFAULT_SIZE) == 0) {
182 __xfs_xattr_put_listent(
183 context, XATTR_SYSTEM_PREFIX,
184 XATTR_SYSTEM_PREFIX_LEN,
185 XATTR_POSIX_ACL_DEFAULT,
186 strlen(XATTR_POSIX_ACL_DEFAULT));
187 }
188 #endif
189
190 /*
191 * Only show root namespace entries if we are actually allowed to
192 * see them.
193 */
194 if (!capable(CAP_SYS_ADMIN))
195 return;
196
197 prefix = XATTR_TRUSTED_PREFIX;
198 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
199 } else if (flags & XFS_ATTR_SECURE) {
200 prefix = XATTR_SECURITY_PREFIX;
201 prefix_len = XATTR_SECURITY_PREFIX_LEN;
202 } else {
203 prefix = XATTR_USER_PREFIX;
204 prefix_len = XATTR_USER_PREFIX_LEN;
205 }
206
207 __xfs_xattr_put_listent(context, prefix, prefix_len, name,
208 namelen);
209 return;
210 }
211
212 ssize_t
xfs_vn_listxattr(struct dentry * dentry,char * data,size_t size)213 xfs_vn_listxattr(
214 struct dentry *dentry,
215 char *data,
216 size_t size)
217 {
218 struct xfs_attr_list_context context;
219 struct attrlist_cursor_kern cursor = { 0 };
220 struct inode *inode = d_inode(dentry);
221 int error;
222
223 /*
224 * First read the regular on-disk attributes.
225 */
226 memset(&context, 0, sizeof(context));
227 context.dp = XFS_I(inode);
228 context.cursor = &cursor;
229 context.resynch = 1;
230 context.alist = size ? data : NULL;
231 context.bufsize = size;
232 context.firstu = context.bufsize;
233 context.put_listent = xfs_xattr_put_listent;
234
235 error = xfs_attr_list_int(&context);
236 if (error)
237 return error;
238 if (context.count < 0)
239 return -ERANGE;
240
241 return context.count;
242 }
243