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1
/*
2
 * Virtio 9p Posix callback
3
 *
4
 * Copyright IBM, Corp. 2010
5
 *
6
 * Authors:
7
 *  Anthony Liguori   <aliguori@us.ibm.com>
8
 *
9
 * This work is licensed under the terms of the GNU GPL, version 2.  See
10
 * the COPYING file in the top-level directory.
11
 *
12
 */
13
#include "virtio.h"
14
#include "virtio-9p.h"
15
#include <arpa/inet.h>
16
#include <pwd.h>
17
#include <grp.h>
18
#include <sys/socket.h>
19
#include <sys/un.h>
20
#include <attr/xattr.h>
21

    
22
static const char *rpath(FsContext *ctx, const char *path)
23
{
24
    /* FIXME: so wrong... */
25
    static char buffer[4096];
26
    snprintf(buffer, sizeof(buffer), "%s/%s", ctx->fs_root, path);
27
    return buffer;
28
}
29

    
30

    
31
static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf)
32
{
33
    int err;
34
    err =  lstat(rpath(fs_ctx, path), stbuf);
35
    if (err) {
36
        return err;
37
    }
38
    if (fs_ctx->fs_sm == SM_MAPPED) {
39
        /* Actual credentials are part of extended attrs */
40
        uid_t tmp_uid;
41
        gid_t tmp_gid;
42
        mode_t tmp_mode;
43
        dev_t tmp_dev;
44
        if (getxattr(rpath(fs_ctx, path), "user.virtfs.uid", &tmp_uid,
45
                    sizeof(uid_t)) > 0) {
46
            stbuf->st_uid = tmp_uid;
47
        }
48
        if (getxattr(rpath(fs_ctx, path), "user.virtfs.gid", &tmp_gid,
49
                    sizeof(gid_t)) > 0) {
50
            stbuf->st_gid = tmp_gid;
51
        }
52
        if (getxattr(rpath(fs_ctx, path), "user.virtfs.mode", &tmp_mode,
53
                    sizeof(mode_t)) > 0) {
54
            stbuf->st_mode = tmp_mode;
55
        }
56
        if (getxattr(rpath(fs_ctx, path), "user.virtfs.rdev", &tmp_dev,
57
                        sizeof(dev_t)) > 0) {
58
                stbuf->st_rdev = tmp_dev;
59
        }
60
    }
61
    return err;
62
}
63

    
64
static int local_set_xattr(const char *path, FsCred *credp)
65
{
66
    int err;
67
    if (credp->fc_uid != -1) {
68
        err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),
69
                0);
70
        if (err) {
71
            return err;
72
        }
73
    }
74
    if (credp->fc_gid != -1) {
75
        err = setxattr(path, "user.virtfs.gid", &credp->fc_gid, sizeof(gid_t),
76
                0);
77
        if (err) {
78
            return err;
79
        }
80
    }
81
    if (credp->fc_mode != -1) {
82
        err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,
83
                sizeof(mode_t), 0);
84
        if (err) {
85
            return err;
86
        }
87
    }
88
    if (credp->fc_rdev != -1) {
89
        err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,
90
                sizeof(dev_t), 0);
91
        if (err) {
92
            return err;
93
        }
94
    }
95
    return 0;
96
}
97

    
98
static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
99
        FsCred *credp)
100
{
101
    if (chmod(rpath(fs_ctx, path), credp->fc_mode & 07777) < 0) {
102
        return -1;
103
    }
104
    if (lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid) < 0) {
105
        /*
106
         * If we fail to change ownership and if we are
107
         * using security model none. Ignore the error
108
         */
109
        if (fs_ctx->fs_sm != SM_NONE) {
110
            return -1;
111
        }
112
    }
113
    return 0;
114
}
115

    
116
static ssize_t local_readlink(FsContext *fs_ctx, const char *path,
117
        char *buf, size_t bufsz)
118
{
119
    ssize_t tsize = -1;
120
    if (fs_ctx->fs_sm == SM_MAPPED) {
121
        int fd;
122
        fd = open(rpath(fs_ctx, path), O_RDONLY);
123
        if (fd == -1) {
124
            return -1;
125
        }
126
        do {
127
            tsize = read(fd, (void *)buf, bufsz);
128
        } while (tsize == -1 && errno == EINTR);
129
        close(fd);
130
        return tsize;
131
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
132
               (fs_ctx->fs_sm == SM_NONE)) {
133
        tsize = readlink(rpath(fs_ctx, path), buf, bufsz);
134
    }
135
    return tsize;
136
}
137

    
138
static int local_close(FsContext *ctx, int fd)
139
{
140
    return close(fd);
141
}
142

    
143
static int local_closedir(FsContext *ctx, DIR *dir)
144
{
145
    return closedir(dir);
146
}
147

    
148
static int local_open(FsContext *ctx, const char *path, int flags)
149
{
150
    return open(rpath(ctx, path), flags);
151
}
152

    
153
static DIR *local_opendir(FsContext *ctx, const char *path)
154
{
155
    return opendir(rpath(ctx, path));
156
}
157

    
158
static void local_rewinddir(FsContext *ctx, DIR *dir)
159
{
160
    return rewinddir(dir);
161
}
162

    
163
static off_t local_telldir(FsContext *ctx, DIR *dir)
164
{
165
    return telldir(dir);
166
}
167

    
168
static struct dirent *local_readdir(FsContext *ctx, DIR *dir)
169
{
170
    return readdir(dir);
171
}
172

    
173
static void local_seekdir(FsContext *ctx, DIR *dir, off_t off)
174
{
175
    return seekdir(dir, off);
176
}
177

    
178
static ssize_t local_readv(FsContext *ctx, int fd, const struct iovec *iov,
179
                            int iovcnt)
180
{
181
    return readv(fd, iov, iovcnt);
182
}
183

    
184
static off_t local_lseek(FsContext *ctx, int fd, off_t offset, int whence)
185
{
186
    return lseek(fd, offset, whence);
187
}
188

    
189
static ssize_t local_writev(FsContext *ctx, int fd, const struct iovec *iov,
190
                            int iovcnt)
191
{
192
    return writev(fd, iov, iovcnt);
193
}
194

    
195
static int local_chmod(FsContext *fs_ctx, const char *path, FsCred *credp)
196
{
197
    if (fs_ctx->fs_sm == SM_MAPPED) {
198
        return local_set_xattr(rpath(fs_ctx, path), credp);
199
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
200
               (fs_ctx->fs_sm == SM_NONE)) {
201
        return chmod(rpath(fs_ctx, path), credp->fc_mode);
202
    }
203
    return -1;
204
}
205

    
206
static int local_mknod(FsContext *fs_ctx, const char *path, FsCred *credp)
207
{
208
    int err = -1;
209
    int serrno = 0;
210

    
211
    /* Determine the security model */
212
    if (fs_ctx->fs_sm == SM_MAPPED) {
213
        err = mknod(rpath(fs_ctx, path), SM_LOCAL_MODE_BITS|S_IFREG, 0);
214
        if (err == -1) {
215
            return err;
216
        }
217
        local_set_xattr(rpath(fs_ctx, path), credp);
218
        if (err == -1) {
219
            serrno = errno;
220
            goto err_end;
221
        }
222
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
223
               (fs_ctx->fs_sm == SM_NONE)) {
224
        err = mknod(rpath(fs_ctx, path), credp->fc_mode, credp->fc_rdev);
225
        if (err == -1) {
226
            return err;
227
        }
228
        err = local_post_create_passthrough(fs_ctx, path, credp);
229
        if (err == -1) {
230
            serrno = errno;
231
            goto err_end;
232
        }
233
    }
234
    return err;
235

    
236
err_end:
237
    remove(rpath(fs_ctx, path));
238
    errno = serrno;
239
    return err;
240
}
241

    
242
static int local_mkdir(FsContext *fs_ctx, const char *path, FsCred *credp)
243
{
244
    int err = -1;
245
    int serrno = 0;
246

    
247
    /* Determine the security model */
248
    if (fs_ctx->fs_sm == SM_MAPPED) {
249
        err = mkdir(rpath(fs_ctx, path), SM_LOCAL_DIR_MODE_BITS);
250
        if (err == -1) {
251
            return err;
252
        }
253
        credp->fc_mode = credp->fc_mode|S_IFDIR;
254
        err = local_set_xattr(rpath(fs_ctx, path), credp);
255
        if (err == -1) {
256
            serrno = errno;
257
            goto err_end;
258
        }
259
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
260
               (fs_ctx->fs_sm == SM_NONE)) {
261
        err = mkdir(rpath(fs_ctx, path), credp->fc_mode);
262
        if (err == -1) {
263
            return err;
264
        }
265
        err = local_post_create_passthrough(fs_ctx, path, credp);
266
        if (err == -1) {
267
            serrno = errno;
268
            goto err_end;
269
        }
270
    }
271
    return err;
272

    
273
err_end:
274
    remove(rpath(fs_ctx, path));
275
    errno = serrno;
276
    return err;
277
}
278

    
279
static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
280
{
281
    int err;
282
    err = fstat(fd, stbuf);
283
    if (err) {
284
        return err;
285
    }
286
    if (fs_ctx->fs_sm == SM_MAPPED) {
287
        /* Actual credentials are part of extended attrs */
288
        uid_t tmp_uid;
289
        gid_t tmp_gid;
290
        mode_t tmp_mode;
291
        dev_t tmp_dev;
292

    
293
        if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
294
            stbuf->st_uid = tmp_uid;
295
        }
296
        if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
297
            stbuf->st_gid = tmp_gid;
298
        }
299
        if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
300
            stbuf->st_mode = tmp_mode;
301
        }
302
        if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
303
                stbuf->st_rdev = tmp_dev;
304
        }
305
    }
306
    return err;
307
}
308

    
309
static int local_open2(FsContext *fs_ctx, const char *path, int flags,
310
        FsCred *credp)
311
{
312
    int fd = -1;
313
    int err = -1;
314
    int serrno = 0;
315

    
316
    /* Determine the security model */
317
    if (fs_ctx->fs_sm == SM_MAPPED) {
318
        fd = open(rpath(fs_ctx, path), flags, SM_LOCAL_MODE_BITS);
319
        if (fd == -1) {
320
            return fd;
321
        }
322
        credp->fc_mode = credp->fc_mode|S_IFREG;
323
        /* Set cleint credentials in xattr */
324
        err = local_set_xattr(rpath(fs_ctx, path), credp);
325
        if (err == -1) {
326
            serrno = errno;
327
            goto err_end;
328
        }
329
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
330
               (fs_ctx->fs_sm == SM_NONE)) {
331
        fd = open(rpath(fs_ctx, path), flags, credp->fc_mode);
332
        if (fd == -1) {
333
            return fd;
334
        }
335
        err = local_post_create_passthrough(fs_ctx, path, credp);
336
        if (err == -1) {
337
            serrno = errno;
338
            goto err_end;
339
        }
340
    }
341
    return fd;
342

    
343
err_end:
344
    close(fd);
345
    remove(rpath(fs_ctx, path));
346
    errno = serrno;
347
    return err;
348
}
349

    
350

    
351
static int local_symlink(FsContext *fs_ctx, const char *oldpath,
352
        const char *newpath, FsCred *credp)
353
{
354
    int err = -1;
355
    int serrno = 0;
356

    
357
    /* Determine the security model */
358
    if (fs_ctx->fs_sm == SM_MAPPED) {
359
        int fd;
360
        ssize_t oldpath_size, write_size;
361
        fd = open(rpath(fs_ctx, newpath), O_CREAT|O_EXCL|O_RDWR,
362
                SM_LOCAL_MODE_BITS);
363
        if (fd == -1) {
364
            return fd;
365
        }
366
        /* Write the oldpath (target) to the file. */
367
        oldpath_size = strlen(oldpath) + 1;
368
        do {
369
            write_size = write(fd, (void *)oldpath, oldpath_size);
370
        } while (write_size == -1 && errno == EINTR);
371

    
372
        if (write_size != oldpath_size) {
373
            serrno = errno;
374
            close(fd);
375
            err = -1;
376
            goto err_end;
377
        }
378
        close(fd);
379
        /* Set cleint credentials in symlink's xattr */
380
        credp->fc_mode = credp->fc_mode|S_IFLNK;
381
        err = local_set_xattr(rpath(fs_ctx, newpath), credp);
382
        if (err == -1) {
383
            serrno = errno;
384
            goto err_end;
385
        }
386
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
387
               (fs_ctx->fs_sm == SM_NONE)) {
388
        err = symlink(oldpath, rpath(fs_ctx, newpath));
389
        if (err) {
390
            return err;
391
        }
392
        err = lchown(rpath(fs_ctx, newpath), credp->fc_uid, credp->fc_gid);
393
        if (err == -1) {
394
            /*
395
             * If we fail to change ownership and if we are
396
             * using security model none. Ignore the error
397
             */
398
            if (fs_ctx->fs_sm != SM_NONE) {
399
                serrno = errno;
400
                goto err_end;
401
            } else
402
                err = 0;
403
        }
404
    }
405
    return err;
406

    
407
err_end:
408
    remove(rpath(fs_ctx, newpath));
409
    errno = serrno;
410
    return err;
411
}
412

    
413
static int local_link(FsContext *ctx, const char *oldpath, const char *newpath)
414
{
415
    char *tmp = qemu_strdup(rpath(ctx, oldpath));
416
    int err, serrno = 0;
417

    
418
    if (tmp == NULL) {
419
        return -ENOMEM;
420
    }
421

    
422
    err = link(tmp, rpath(ctx, newpath));
423
    if (err == -1) {
424
        serrno = errno;
425
    }
426

    
427
    qemu_free(tmp);
428

    
429
    if (err == -1) {
430
        errno = serrno;
431
    }
432

    
433
    return err;
434
}
435

    
436
static int local_truncate(FsContext *ctx, const char *path, off_t size)
437
{
438
    return truncate(rpath(ctx, path), size);
439
}
440

    
441
static int local_rename(FsContext *ctx, const char *oldpath,
442
                        const char *newpath)
443
{
444
    char *tmp;
445
    int err;
446

    
447
    tmp = qemu_strdup(rpath(ctx, oldpath));
448

    
449
    err = rename(tmp, rpath(ctx, newpath));
450
    if (err == -1) {
451
        int serrno = errno;
452
        qemu_free(tmp);
453
        errno = serrno;
454
    } else {
455
        qemu_free(tmp);
456
    }
457

    
458
    return err;
459

    
460
}
461

    
462
static int local_chown(FsContext *fs_ctx, const char *path, FsCred *credp)
463
{
464
    if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
465
            (fs_ctx->fs_sm == SM_PASSTHROUGH)) {
466
        return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
467
    } else if (fs_ctx->fs_sm == SM_MAPPED) {
468
        return local_set_xattr(rpath(fs_ctx, path), credp);
469
    } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
470
               (fs_ctx->fs_sm == SM_NONE)) {
471
        return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
472
    }
473
    return -1;
474
}
475

    
476
static int local_utimensat(FsContext *s, const char *path,
477
                       const struct timespec *buf)
478
{
479
    return utimensat(AT_FDCWD, rpath(s, path), buf, AT_SYMLINK_NOFOLLOW);
480
}
481

    
482
static int local_remove(FsContext *ctx, const char *path)
483
{
484
    return remove(rpath(ctx, path));
485
}
486

    
487
static int local_fsync(FsContext *ctx, int fd)
488
{
489
    return fsync(fd);
490
}
491

    
492
static int local_statfs(FsContext *s, const char *path, struct statfs *stbuf)
493
{
494
   return statfs(rpath(s, path), stbuf);
495
}
496

    
497
static ssize_t local_lgetxattr(FsContext *ctx, const char *path,
498
                               const char *name, void *value, size_t size)
499
{
500
    if ((ctx->fs_sm == SM_MAPPED) &&
501
        (strncmp(name, "user.virtfs.", 12) == 0)) {
502
        /*
503
         * Don't allow fetch of user.virtfs namesapce
504
         * in case of mapped security
505
         */
506
        errno = ENOATTR;
507
        return -1;
508
    }
509

    
510
    return lgetxattr(rpath(ctx, path), name, value, size);
511
}
512

    
513
static ssize_t local_llistxattr(FsContext *ctx, const char *path,
514
                                void *value, size_t size)
515
{
516
    ssize_t retval;
517
    ssize_t actual_len = 0;
518
    char *orig_value, *orig_value_start;
519
    char *temp_value, *temp_value_start;
520
    ssize_t xattr_len, parsed_len = 0, attr_len;
521

    
522
    if (ctx->fs_sm != SM_MAPPED) {
523
        return llistxattr(rpath(ctx, path), value, size);
524
    }
525

    
526
    /* Get the actual len */
527
    xattr_len = llistxattr(rpath(ctx, path), value, 0);
528

    
529
    /* Now fetch the xattr and find the actual size */
530
    orig_value = qemu_malloc(xattr_len);
531
    xattr_len = llistxattr(rpath(ctx, path), orig_value, xattr_len);
532

    
533
    /*
534
     * For mapped security model drop user.virtfs namespace
535
     * from the list
536
     */
537
    temp_value = qemu_mallocz(xattr_len);
538
    temp_value_start = temp_value;
539
    orig_value_start = orig_value;
540
    while (xattr_len > parsed_len) {
541
        attr_len = strlen(orig_value) + 1;
542
        if (strncmp(orig_value, "user.virtfs.", 12) != 0) {
543
            /* Copy this entry */
544
            strcat(temp_value, orig_value);
545
            temp_value  += attr_len;
546
            actual_len += attr_len;
547
        }
548
        parsed_len += attr_len;
549
        orig_value += attr_len;
550
    }
551
    if (!size) {
552
        retval = actual_len;
553
        goto out;
554
    } else if (size >= actual_len) {
555
        /* now copy the parsed attribute list back */
556
        memset(value, 0, size);
557
        memcpy(value, temp_value_start, actual_len);
558
        retval = actual_len;
559
        goto out;
560
    }
561
    errno = ERANGE;
562
    retval = -1;
563
out:
564
    qemu_free(orig_value_start);
565
    qemu_free(temp_value_start);
566
    return retval;
567
}
568

    
569
static int local_lsetxattr(FsContext *ctx, const char *path, const char *name,
570
                           void *value, size_t size, int flags)
571
{
572
    if ((ctx->fs_sm == SM_MAPPED) &&
573
        (strncmp(name, "user.virtfs.", 12) == 0)) {
574
        /*
575
         * Don't allow fetch of user.virtfs namesapce
576
         * in case of mapped security
577
         */
578
        errno = EACCES;
579
        return -1;
580
    }
581
    return lsetxattr(rpath(ctx, path), name, value, size, flags);
582
}
583

    
584
static int local_lremovexattr(FsContext *ctx,
585
                              const char *path, const char *name)
586
{
587
    if ((ctx->fs_sm == SM_MAPPED) &&
588
        (strncmp(name, "user.virtfs.", 12) == 0)) {
589
        /*
590
         * Don't allow fetch of user.virtfs namesapce
591
         * in case of mapped security
592
         */
593
        errno = EACCES;
594
        return -1;
595
    }
596
    return lremovexattr(rpath(ctx, path), name);
597
}
598

    
599

    
600
FileOperations local_ops = {
601
    .lstat = local_lstat,
602
    .readlink = local_readlink,
603
    .close = local_close,
604
    .closedir = local_closedir,
605
    .open = local_open,
606
    .opendir = local_opendir,
607
    .rewinddir = local_rewinddir,
608
    .telldir = local_telldir,
609
    .readdir = local_readdir,
610
    .seekdir = local_seekdir,
611
    .readv = local_readv,
612
    .lseek = local_lseek,
613
    .writev = local_writev,
614
    .chmod = local_chmod,
615
    .mknod = local_mknod,
616
    .mkdir = local_mkdir,
617
    .fstat = local_fstat,
618
    .open2 = local_open2,
619
    .symlink = local_symlink,
620
    .link = local_link,
621
    .truncate = local_truncate,
622
    .rename = local_rename,
623
    .chown = local_chown,
624
    .utimensat = local_utimensat,
625
    .remove = local_remove,
626
    .fsync = local_fsync,
627
    .statfs = local_statfs,
628
    .lgetxattr = local_lgetxattr,
629
    .llistxattr = local_llistxattr,
630
    .lsetxattr = local_lsetxattr,
631
    .lremovexattr = local_lremovexattr,
632
};