1 // SPDX-License-Identifier: LGPL-2.1 2 /* 3 * Copyright IBM Corporation, 2010 4 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> 5 */ 6 7 #include <linux/module.h> 8 #include <linux/fs.h> 9 #include <linux/sched.h> 10 #include <linux/uio.h> 11 #include <linux/posix_acl_xattr.h> 12 #include <net/9p/9p.h> 13 #include <net/9p/client.h> 14 15 #include "fid.h" 16 #include "xattr.h" 17 18 ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name, 19 void *buffer, size_t buffer_size) 20 { 21 ssize_t retval; 22 u64 attr_size; 23 struct p9_fid *attr_fid; 24 struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size}; 25 struct iov_iter to; 26 int err; 27 28 iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size); 29 30 attr_fid = p9_client_xattrwalk(fid, name, &attr_size); 31 if (IS_ERR(attr_fid)) { 32 retval = PTR_ERR(attr_fid); 33 p9_debug(P9_DEBUG_VFS, "p9_client_attrwalk failed %zd\n", 34 retval); 35 return retval; 36 } 37 if (attr_size > buffer_size) { 38 if (buffer_size) 39 retval = -ERANGE; 40 else if (attr_size > SSIZE_MAX) 41 retval = -EOVERFLOW; 42 else /* request to get the attr_size */ 43 retval = attr_size; 44 } else { 45 iov_iter_truncate(&to, attr_size); 46 retval = p9_client_read(attr_fid, 0, &to, &err); 47 if (err) 48 retval = err; 49 } 50 p9_fid_put(attr_fid); 51 return retval; 52 } 53 54 55 /* 56 * v9fs_xattr_get() 57 * 58 * Copy an extended attribute into the buffer 59 * provided, or compute the buffer size required. 60 * Buffer is NULL to compute the size of the buffer required. 61 * 62 * Returns a negative error number on failure, or the number of bytes 63 * used / required on success. 64 */ 65 ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name, 66 void *buffer, size_t buffer_size) 67 { 68 struct p9_fid *fid; 69 int ret; 70 71 p9_debug(P9_DEBUG_VFS, "name = '%s' value_len = %zu\n", 72 name, buffer_size); 73 fid = v9fs_fid_lookup(dentry); 74 if (IS_ERR(fid)) 75 return PTR_ERR(fid); 76 ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size); 77 p9_fid_put(fid); 78 79 return ret; 80 } 81 82 /* 83 * v9fs_xattr_set() 84 * 85 * Create, replace or remove an extended attribute for this inode. Buffer 86 * is NULL to remove an existing extended attribute, and non-NULL to 87 * either replace an existing extended attribute, or create a new extended 88 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 89 * specify that an extended attribute must exist and must not exist 90 * previous to the call, respectively. 91 * 92 * Returns 0, or a negative error number on failure. 93 */ 94 int v9fs_xattr_set(struct dentry *dentry, const char *name, 95 const void *value, size_t value_len, int flags) 96 { 97 int ret; 98 struct p9_fid *fid; 99 100 fid = v9fs_fid_lookup(dentry); 101 if (IS_ERR(fid)) 102 return PTR_ERR(fid); 103 ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags); 104 p9_fid_put(fid); 105 return ret; 106 } 107 108 int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name, 109 const void *value, size_t value_len, int flags) 110 { 111 struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len}; 112 struct iov_iter from; 113 int retval, err; 114 115 iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len); 116 117 p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n", 118 name, value_len, flags); 119 120 /* Clone it */ 121 fid = clone_fid(fid); 122 if (IS_ERR(fid)) 123 return PTR_ERR(fid); 124 125 /* 126 * On success fid points to xattr 127 */ 128 retval = p9_client_xattrcreate(fid, name, value_len, flags); 129 if (retval < 0) 130 p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n", 131 retval); 132 else 133 p9_client_write(fid, 0, &from, &retval); 134 err = p9_fid_put(fid); 135 if (!retval && err) 136 retval = err; 137 return retval; 138 } 139 140 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 141 { 142 /* Txattrwalk with an empty string lists xattrs instead */ 143 return v9fs_xattr_get(dentry, "", buffer, buffer_size); 144 } 145 146 static int v9fs_xattr_handler_get(const struct xattr_handler *handler, 147 struct dentry *dentry, struct inode *inode, 148 const char *name, void *buffer, size_t size) 149 { 150 const char *full_name = xattr_full_name(handler, name); 151 152 return v9fs_xattr_get(dentry, full_name, buffer, size); 153 } 154 155 static int v9fs_xattr_handler_set(const struct xattr_handler *handler, 156 struct mnt_idmap *idmap, 157 struct dentry *dentry, struct inode *inode, 158 const char *name, const void *value, 159 size_t size, int flags) 160 { 161 const char *full_name = xattr_full_name(handler, name); 162 163 return v9fs_xattr_set(dentry, full_name, value, size, flags); 164 } 165 166 static const struct xattr_handler v9fs_xattr_user_handler = { 167 .prefix = XATTR_USER_PREFIX, 168 .get = v9fs_xattr_handler_get, 169 .set = v9fs_xattr_handler_set, 170 }; 171 172 static const struct xattr_handler v9fs_xattr_trusted_handler = { 173 .prefix = XATTR_TRUSTED_PREFIX, 174 .get = v9fs_xattr_handler_get, 175 .set = v9fs_xattr_handler_set, 176 }; 177 178 #ifdef CONFIG_9P_FS_SECURITY 179 static const struct xattr_handler v9fs_xattr_security_handler = { 180 .prefix = XATTR_SECURITY_PREFIX, 181 .get = v9fs_xattr_handler_get, 182 .set = v9fs_xattr_handler_set, 183 }; 184 #endif 185 186 const struct xattr_handler * const v9fs_xattr_handlers[] = { 187 &v9fs_xattr_user_handler, 188 &v9fs_xattr_trusted_handler, 189 #ifdef CONFIG_9P_FS_SECURITY 190 &v9fs_xattr_security_handler, 191 #endif 192 NULL 193 }; 194