On Mon, Oct 17, 2022 at 3:09 AM Jack Wang <jinpu.wang@xxxxxxxxx> wrote:
>
> From: Florian-Ewald Mueller <florian-ewald.mueller@xxxxxxxxx>
>
> - 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@xxxxxxxxxxxxxxx
>
> Signed-off-by: Florian-Ewald Mueller <florian-ewald.mueller@xxxxxxxxx>
> Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx>
Applied to md-next. Thanks!
Song
> ---
> v1->v2: extend commit message for steps to reproduce the problem.
> fix the warning reported by buildbot
>
> drivers/md/md-bitmap.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
> index bf6dffadbe6f..d4bf7f603ef6 100644
> --- a/drivers/md/md-bitmap.c
> +++ b/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;
> @@ -2534,6 +2535,9 @@ chunksize_store(struct mddev *mddev, const char *buf, size_t len)
> if (csize < 512 ||
> !is_power_of_2(csize))
> return -EINVAL;
> + if (csize >= (1ULL << (BITS_PER_BYTE *
> + sizeof(((bitmap_super_t *)0)->chunksize))))
> + return -EOVERFLOW;
> mddev->bitmap_info.chunksize = csize;
> return len;
> }
> --
> 2.34.1
>
