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2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771 
 kernel/fs/nilfs2/the_nilfs.c
....@@ -13,6 +13,7 @@
1313 #include <linux/blkdev.h>
1414 #include <linux/backing-dev.h>
1515 #include <linux/random.h>
16
+#include <linux/log2.h>
1617 #include <linux/crc32.h>
1718 #include "nilfs.h"
1819 #include "segment.h"
....@@ -86,7 +87,6 @@
8687 {
8788 	might_sleep();
8889 	if (nilfs_init(nilfs)) {
89
-		nilfs_sysfs_delete_device_group(nilfs);
9090 		brelse(nilfs->ns_sbh[0]);
9191 		brelse(nilfs->ns_sbh[1]);
9292 	}
....@@ -193,6 +193,34 @@
193193 }
194194 
195195 /**
196
+ * nilfs_get_blocksize - get block size from raw superblock data
197
+ * @sb: super block instance
198
+ * @sbp: superblock raw data buffer
199
+ * @blocksize: place to store block size
200
+ *
201
+ * nilfs_get_blocksize() calculates the block size from the block size
202
+ * exponent information written in @sbp and stores it in @blocksize,
203
+ * or aborts with an error message if it's too large.
204
+ *
205
+ * Return Value: On success, 0 is returned. If the block size is too
206
+ * large, -EINVAL is returned.
207
+ */
208
+static int nilfs_get_blocksize(struct super_block *sb,
209
+			       struct nilfs_super_block *sbp, int *blocksize)
210
+{
211
+	unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
212
+
213
+	if (unlikely(shift_bits >
214
+		     ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)) {
215
+		nilfs_err(sb, "too large filesystem blocksize: 2 ^ %u KiB",
216
+			  shift_bits);
217
+		return -EINVAL;
218
+	}
219
+	*blocksize = BLOCK_SIZE << shift_bits;
220
+	return 0;
221
+}
222
+
223
+/**
196224  * load_nilfs - load and recover the nilfs
197225  * @nilfs: the_nilfs structure to be released
198226  * @sb: super block isntance used to recover past segment
....@@ -245,11 +273,15 @@
245273 		nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
246274 
247275 		/* verify consistency between two super blocks */
248
-		blocksize = BLOCK_SIZE << le32_to_cpu(sbp[0]->s_log_block_size);
276
+		err = nilfs_get_blocksize(sb, sbp[0], &blocksize);
277
+		if (err)
278
+			goto scan_error;
279
+
249280 		if (blocksize != nilfs->ns_blocksize) {
250281 			nilfs_warn(sb,
251282 				   "blocksize differs between two super blocks (%d != %d)",
252283 				   blocksize, nilfs->ns_blocksize);
284
+			err = -EINVAL;
253285 			goto scan_error;
254286 		}
255287 
....@@ -271,6 +303,10 @@
271303 		nilfs_err(sb, "error %d while loading super root", err);
272304 		goto failed;
273305 	}
306
+
307
+	err = nilfs_sysfs_create_device_group(sb);
308
+	if (unlikely(err))
309
+		goto sysfs_error;
274310 
275311 	if (valid_fs)
276312 		goto skip_recovery;
....@@ -333,6 +369,9 @@
333369 	goto failed;
334370 
335371  failed_unload:
372
+	nilfs_sysfs_delete_device_group(nilfs);
373
+
374
+ sysfs_error:
336375 	iput(nilfs->ns_cpfile);
337376 	iput(nilfs->ns_sufile);
338377 	iput(nilfs->ns_dat);
....@@ -366,6 +405,18 @@
366405 				  100));
367406 }
368407 
408
+/**
409
+ * nilfs_max_segment_count - calculate the maximum number of segments
410
+ * @nilfs: nilfs object
411
+ */
412
+static u64 nilfs_max_segment_count(struct the_nilfs *nilfs)
413
+{
414
+	u64 max_count = U64_MAX;
415
+
416
+	do_div(max_count, nilfs->ns_blocks_per_segment);
417
+	return min_t(u64, max_count, ULONG_MAX);
418
+}
419
+
369420 void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs)
370421 {
371422 	nilfs->ns_nsegments = nsegs;
....@@ -375,6 +426,8 @@
375426 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
376427 				   struct nilfs_super_block *sbp)
377428 {
429
+	u64 nsegments, nblocks;
430
+
378431 	if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
379432 		nilfs_err(nilfs->ns_sb,
380433 			  "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).",
....@@ -418,7 +471,35 @@
418471 		return -EINVAL;
419472 	}
420473 
421
-	nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments));
474
+	nsegments = le64_to_cpu(sbp->s_nsegments);
475
+	if (nsegments > nilfs_max_segment_count(nilfs)) {
476
+		nilfs_err(nilfs->ns_sb,
477
+			  "segment count %llu exceeds upper limit (%llu segments)",
478
+			  (unsigned long long)nsegments,
479
+			  (unsigned long long)nilfs_max_segment_count(nilfs));
480
+		return -EINVAL;
481
+	}
482
+
483
+	nblocks = (u64)i_size_read(nilfs->ns_sb->s_bdev->bd_inode) >>
484
+		nilfs->ns_sb->s_blocksize_bits;
485
+	if (nblocks) {
486
+		u64 min_block_count = nsegments * nilfs->ns_blocks_per_segment;
487
+		/*
488
+		 * To avoid failing to mount early device images without a
489
+		 * second superblock, exclude that block count from the
490
+		 * "min_block_count" calculation.
491
+		 */
492
+
493
+		if (nblocks < min_block_count) {
494
+			nilfs_err(nilfs->ns_sb,
495
+				  "total number of segment blocks %llu exceeds device size (%llu blocks)",
496
+				  (unsigned long long)min_block_count,
497
+				  (unsigned long long)nblocks);
498
+			return -EINVAL;
499
+		}
500
+	}
501
+
502
+	nilfs_set_nsegments(nilfs, nsegments);
422503 	nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
423504 	return 0;
424505 }
....@@ -443,11 +524,33 @@
443524 	return crc == le32_to_cpu(sbp->s_sum);
444525 }
445526 
446
-static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
527
+/**
528
+ * nilfs_sb2_bad_offset - check the location of the second superblock
529
+ * @sbp: superblock raw data buffer
530
+ * @offset: byte offset of second superblock calculated from device size
531
+ *
532
+ * nilfs_sb2_bad_offset() checks if the position on the second
533
+ * superblock is valid or not based on the filesystem parameters
534
+ * stored in @sbp.  If @offset points to a location within the segment
535
+ * area, or if the parameters themselves are not normal, it is
536
+ * determined to be invalid.
537
+ *
538
+ * Return Value: true if invalid, false if valid.
539
+ */
540
+static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
447541 {
448
-	return offset < ((le64_to_cpu(sbp->s_nsegments) *
449
-			  le32_to_cpu(sbp->s_blocks_per_segment)) <<
450
-			 (le32_to_cpu(sbp->s_log_block_size) + 10));
542
+	unsigned int shift_bits = le32_to_cpu(sbp->s_log_block_size);
543
+	u32 blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
544
+	u64 nsegments = le64_to_cpu(sbp->s_nsegments);
545
+	u64 index;
546
+
547
+	if (blocks_per_segment < NILFS_SEG_MIN_BLOCKS ||
548
+	    shift_bits > ilog2(NILFS_MAX_BLOCK_SIZE) - BLOCK_SIZE_BITS)
549
+		return true;
550
+
551
+	index = offset >> (shift_bits + BLOCK_SIZE_BITS);
552
+	do_div(index, blocks_per_segment);
553
+	return index < nsegments;
451554 }
452555 
453556 static void nilfs_release_super_block(struct the_nilfs *nilfs)
....@@ -489,8 +592,14 @@
489592 {
490593 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
491594 	struct buffer_head **sbh = nilfs->ns_sbh;
492
-	u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size);
595
+	u64 sb2off, devsize = nilfs->ns_bdev->bd_inode->i_size;
493596 	int valid[2], swp = 0;
597
+
598
+	if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) {
599
+		nilfs_err(sb, "device size too small");
600
+		return -EINVAL;
601
+	}
602
+	sb2off = NILFS_SB2_OFFSET_BYTES(devsize);
494603 
495604 	sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize,
496605 					&sbh[0]);
....@@ -586,9 +695,11 @@
586695 	if (err)
587696 		goto failed_sbh;
588697 
589
-	blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
590
-	if (blocksize < NILFS_MIN_BLOCK_SIZE ||
591
-	    blocksize > NILFS_MAX_BLOCK_SIZE) {
698
+	err = nilfs_get_blocksize(sb, sbp, &blocksize);
699
+	if (err)
700
+		goto failed_sbh;
701
+
702
+	if (blocksize < NILFS_MIN_BLOCK_SIZE) {
592703 		nilfs_err(sb,
593704 			  "couldn't mount because of unsupported filesystem blocksize %d",
594705 			  blocksize);
....@@ -631,10 +742,6 @@
631742 	nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
632743 
633744 	err = nilfs_store_log_cursor(nilfs, sbp);
634
-	if (err)
635
-		goto failed_sbh;
636
-
637
-	err = nilfs_sysfs_create_device_group(sb);
638745 	if (err)
639746 		goto failed_sbh;
640747