md/bitmap: Fix bitmap chunk size overflow issues

- limit bitmap chunk size internal u64 variable to values not overflowing
  the u32 bitmap superblock structure variable stored on persistent media
- assign bitmap chunk size internal u64 variable from unsigned values to
  avoid possible sign extension artifacts when assigning from a s32 value

The bug has been there since at least kernel 4.0.
Steps to reproduce it:
1: mdadm -C /dev/mdx -l 1 --bitmap=internal --bitmap-chunk=256M -e 1.2
-n2 /dev/rnbd1 /dev/rnbd2
2 resize member device rnbd1 and rnbd2 to 8 TB
3 mdadm --grow /dev/mdx --size=max

The bitmap_chunksize will overflow without patch.

Cc: stable@vger.kernel.org
Signed-off-by: Florian-Ewald Mueller <florian-ewald.mueller@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Song Liu <song@kernel.org>

drivers/md/md-bitmap.c

@@ -486,7 +486,7 @@ void md_bitmap_print_sb(struct bitmap *bitmap)
 	sb = kmap_atomic(bitmap->storage.sb_page);
 	pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
 	pr_debug("         magic: %08x\n", le32_to_cpu(sb->magic));
-	pr_debug("       version: %d\n", le32_to_cpu(sb->version));
+	pr_debug("       version: %u\n", le32_to_cpu(sb->version));
 	pr_debug("          uuid: %08x.%08x.%08x.%08x\n",
 		 le32_to_cpu(*(__le32 *)(sb->uuid+0)),
 		 le32_to_cpu(*(__le32 *)(sb->uuid+4)),
@@ -497,11 +497,11 @@ void md_bitmap_print_sb(struct bitmap *bitmap)
 	pr_debug("events cleared: %llu\n",
 		 (unsigned long long) le64_to_cpu(sb->events_cleared));
 	pr_debug("         state: %08x\n", le32_to_cpu(sb->state));
-	pr_debug("     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
-	pr_debug("  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
+	pr_debug("     chunksize: %u B\n", le32_to_cpu(sb->chunksize));
+	pr_debug("  daemon sleep: %us\n", le32_to_cpu(sb->daemon_sleep));
 	pr_debug("     sync size: %llu KB\n",
 		 (unsigned long long)le64_to_cpu(sb->sync_size)/2);
-	pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
+	pr_debug("max write behind: %u\n", le32_to_cpu(sb->write_behind));
 	kunmap_atomic(sb);
 }
 
@@ -2105,7 +2105,8 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 			bytes = DIV_ROUND_UP(chunks, 8);
 			if (!bitmap->mddev->bitmap_info.external)
 				bytes += sizeof(bitmap_super_t);
-		} while (bytes > (space << 9));
+		} while (bytes > (space << 9) && (chunkshift + BITMAP_BLOCK_SHIFT) <
+			(BITS_PER_BYTE * sizeof(((bitmap_super_t *)0)->chunksize) - 1));
 	} else
 		chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
 
@@ -2150,7 +2151,7 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 	bitmap->counts.missing_pages = pages;
 	bitmap->counts.chunkshift = chunkshift;
 	bitmap->counts.chunks = chunks;
-	bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
+	bitmap->mddev->bitmap_info.chunksize = 1UL << (chunkshift +
 						     BITMAP_BLOCK_SHIFT);
 
 	blocks = min(old_counts.chunks << old_counts.chunkshift,
@@ -2176,8 +2177,8 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 				bitmap->counts.missing_pages = old_counts.pages;
 				bitmap->counts.chunkshift = old_counts.chunkshift;
 				bitmap->counts.chunks = old_counts.chunks;
-				bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
-									     BITMAP_BLOCK_SHIFT);
+				bitmap->mddev->bitmap_info.chunksize =
+					1UL << (old_counts.chunkshift + BITMAP_BLOCK_SHIFT);
 				blocks = old_counts.chunks << old_counts.chunkshift;
 				pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
 				break;
@@ -2537,6 +2538,9 @@ chunksize_store(struct mddev *mddev, const char *buf, size_t len)
 	if (csize < 512 ||
 	    !is_power_of_2(csize))
 		return -EINVAL;
+	if (BITS_PER_LONG > 32 && csize >= (1ULL << (BITS_PER_BYTE *
+		sizeof(((bitmap_super_t *)0)->chunksize))))
+		return -EOVERFLOW;
 	mddev->bitmap_info.chunksize = csize;
 	return len;
 }