On Mon, Oct 17, 2022 at 3:09 AM Jack Wang jinpu.wang@ionos.com wrote:

From: Florian-Ewald Mueller florian-ewald.mueller@ionos.com

• 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

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