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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 | // SPDX-License-Identifier: GPL-2.0 #include <linux/syscalls.h> #include <linux/export.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/mount.h> #include <linux/namei.h> #include <linux/statfs.h> #include <linux/security.h> #include <linux/uaccess.h> #include <linux/compat.h> #include "internal.h" static int flags_by_mnt(int mnt_flags) { int flags = 0; if (mnt_flags & MNT_READONLY) flags |= ST_RDONLY; if (mnt_flags & MNT_NOSUID) flags |= ST_NOSUID; if (mnt_flags & MNT_NODEV) flags |= ST_NODEV; if (mnt_flags & MNT_NOEXEC) flags |= ST_NOEXEC; if (mnt_flags & MNT_NOATIME) flags |= ST_NOATIME; if (mnt_flags & MNT_NODIRATIME) flags |= ST_NODIRATIME; if (mnt_flags & MNT_RELATIME) flags |= ST_RELATIME; if (mnt_flags & MNT_NOSYMFOLLOW) flags |= ST_NOSYMFOLLOW; return flags; } static int flags_by_sb(int s_flags) { int flags = 0; if (s_flags & SB_SYNCHRONOUS) flags |= ST_SYNCHRONOUS; if (s_flags & SB_MANDLOCK) flags |= ST_MANDLOCK; if (s_flags & SB_RDONLY) flags |= ST_RDONLY; return flags; } static int calculate_f_flags(struct vfsmount *mnt) { return ST_VALID | flags_by_mnt(mnt->mnt_flags) | flags_by_sb(mnt->mnt_sb->s_flags); } static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf) { int retval; if (!dentry->d_sb->s_op->statfs) return -ENOSYS; memset(buf, 0, sizeof(*buf)); retval = security_sb_statfs(dentry); if (retval) return retval; retval = dentry->d_sb->s_op->statfs(dentry, buf); if (retval == 0 && buf->f_frsize == 0) buf->f_frsize = buf->f_bsize; return retval; } int vfs_get_fsid(struct dentry *dentry, __kernel_fsid_t *fsid) { struct kstatfs st; int error; error = statfs_by_dentry(dentry, &st); if (error) return error; *fsid = st.f_fsid; return 0; } EXPORT_SYMBOL(vfs_get_fsid); int vfs_statfs(const struct path *path, struct kstatfs *buf) { int error; error = statfs_by_dentry(path->dentry, buf); if (!error) buf->f_flags = calculate_f_flags(path->mnt); return error; } EXPORT_SYMBOL(vfs_statfs); int user_statfs(const char __user *pathname, struct kstatfs *st) { struct path path; int error; unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT; retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (!error) { error = vfs_statfs(&path, st); path_put(&path); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } } return error; } int fd_statfs(int fd, struct kstatfs *st) { struct fd f = fdget_raw(fd); int error = -EBADF; if (f.file) { error = vfs_statfs(&f.file->f_path, st); fdput(f); } return error; } static int do_statfs_native(struct kstatfs *st, struct statfs __user *p) { struct statfs buf; if (sizeof(buf) == sizeof(*st)) memcpy(&buf, st, sizeof(*st)); else { if (sizeof buf.f_blocks == 4) { if ((st->f_blocks | st->f_bfree | st->f_bavail | st->f_bsize | st->f_frsize) & 0xffffffff00000000ULL) return -EOVERFLOW; /* * f_files and f_ffree may be -1; it's okay to stuff * that into 32 bits */ if (st->f_files != -1 && (st->f_files & 0xffffffff00000000ULL)) return -EOVERFLOW; if (st->f_ffree != -1 && (st->f_ffree & 0xffffffff00000000ULL)) return -EOVERFLOW; } buf.f_type = st->f_type; buf.f_bsize = st->f_bsize; buf.f_blocks = st->f_blocks; buf.f_bfree = st->f_bfree; buf.f_bavail = st->f_bavail; buf.f_files = st->f_files; buf.f_ffree = st->f_ffree; buf.f_fsid = st->f_fsid; buf.f_namelen = st->f_namelen; buf.f_frsize = st->f_frsize; buf.f_flags = st->f_flags; memset(buf.f_spare, 0, sizeof(buf.f_spare)); } if (copy_to_user(p, &buf, sizeof(buf))) return -EFAULT; return 0; } static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p) { struct statfs64 buf; if (sizeof(buf) == sizeof(*st)) memcpy(&buf, st, sizeof(*st)); else { buf.f_type = st->f_type; buf.f_bsize = st->f_bsize; buf.f_blocks = st->f_blocks; buf.f_bfree = st->f_bfree; buf.f_bavail = st->f_bavail; buf.f_files = st->f_files; buf.f_ffree = st->f_ffree; buf.f_fsid = st->f_fsid; buf.f_namelen = st->f_namelen; buf.f_frsize = st->f_frsize; buf.f_flags = st->f_flags; memset(buf.f_spare, 0, sizeof(buf.f_spare)); } if (copy_to_user(p, &buf, sizeof(buf))) return -EFAULT; return 0; } SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf) { struct kstatfs st; int error = user_statfs(pathname, &st); if (!error) error = do_statfs_native(&st, buf); return error; } SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf) { struct kstatfs st; int error; if (sz != sizeof(*buf)) return -EINVAL; error = user_statfs(pathname, &st); if (!error) error = do_statfs64(&st, buf); return error; } SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf) { struct kstatfs st; int error = fd_statfs(fd, &st); if (!error) error = do_statfs_native(&st, buf); return error; } SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf) { struct kstatfs st; int error; if (sz != sizeof(*buf)) return -EINVAL; error = fd_statfs(fd, &st); if (!error) error = do_statfs64(&st, buf); return error; } static int vfs_ustat(dev_t dev, struct kstatfs *sbuf) { struct super_block *s = user_get_super(dev); int err; if (!s) return -EINVAL; err = statfs_by_dentry(s->s_root, sbuf); drop_super(s); return err; } SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) { struct ustat tmp; struct kstatfs sbuf; int err = vfs_ustat(new_decode_dev(dev), &sbuf); if (err) return err; memset(&tmp,0,sizeof(struct ustat)); tmp.f_tfree = sbuf.f_bfree; tmp.f_tinode = sbuf.f_ffree; return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0; } #ifdef CONFIG_COMPAT static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf) { struct compat_statfs buf; if (sizeof ubuf->f_blocks == 4) { if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail | kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) return -EOVERFLOW; /* f_files and f_ffree may be -1; it's okay * to stuff that into 32 bits */ if (kbuf->f_files != 0xffffffffffffffffULL && (kbuf->f_files & 0xffffffff00000000ULL)) return -EOVERFLOW; if (kbuf->f_ffree != 0xffffffffffffffffULL && (kbuf->f_ffree & 0xffffffff00000000ULL)) return -EOVERFLOW; } memset(&buf, 0, sizeof(struct compat_statfs)); buf.f_type = kbuf->f_type; buf.f_bsize = kbuf->f_bsize; buf.f_blocks = kbuf->f_blocks; buf.f_bfree = kbuf->f_bfree; buf.f_bavail = kbuf->f_bavail; buf.f_files = kbuf->f_files; buf.f_ffree = kbuf->f_ffree; buf.f_namelen = kbuf->f_namelen; buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; buf.f_frsize = kbuf->f_frsize; buf.f_flags = kbuf->f_flags; if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs))) return -EFAULT; return 0; } /* * The following statfs calls are copies of code from fs/statfs.c and * should be checked against those from time to time */ COMPAT_SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct compat_statfs __user *, buf) { struct kstatfs tmp; int error = user_statfs(pathname, &tmp); if (!error) error = put_compat_statfs(buf, &tmp); return error; } COMPAT_SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct compat_statfs __user *, buf) { struct kstatfs tmp; int error = fd_statfs(fd, &tmp); if (!error) error = put_compat_statfs(buf, &tmp); return error; } static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf) { struct compat_statfs64 buf; if ((kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) return -EOVERFLOW; memset(&buf, 0, sizeof(struct compat_statfs64)); buf.f_type = kbuf->f_type; buf.f_bsize = kbuf->f_bsize; buf.f_blocks = kbuf->f_blocks; buf.f_bfree = kbuf->f_bfree; buf.f_bavail = kbuf->f_bavail; buf.f_files = kbuf->f_files; buf.f_ffree = kbuf->f_ffree; buf.f_namelen = kbuf->f_namelen; buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; buf.f_frsize = kbuf->f_frsize; buf.f_flags = kbuf->f_flags; if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs64))) return -EFAULT; return 0; } int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf) { struct kstatfs tmp; int error; if (sz != sizeof(*buf)) return -EINVAL; error = user_statfs(pathname, &tmp); if (!error) error = put_compat_statfs64(buf, &tmp); return error; } COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf) { return kcompat_sys_statfs64(pathname, sz, buf); } int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf) { struct kstatfs tmp; int error; if (sz != sizeof(*buf)) return -EINVAL; error = fd_statfs(fd, &tmp); if (!error) error = put_compat_statfs64(buf, &tmp); return error; } COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf) { return kcompat_sys_fstatfs64(fd, sz, buf); } /* * This is a copy of sys_ustat, just dealing with a structure layout. * Given how simple this syscall is that apporach is more maintainable * than the various conversion hacks. */ COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u) { struct compat_ustat tmp; struct kstatfs sbuf; int err = vfs_ustat(new_decode_dev(dev), &sbuf); if (err) return err; memset(&tmp, 0, sizeof(struct compat_ustat)); tmp.f_tfree = sbuf.f_bfree; tmp.f_tinode = sbuf.f_ffree; if (copy_to_user(u, &tmp, sizeof(struct compat_ustat))) return -EFAULT; return 0; } #endif |