The patch titled Subject: nilfs2: fix data corruption in dsync block recovery for small block sizes has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-data-corruption-in-dsync-block-recovery-for-small-block-sizes.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Ryusuke Konishi konishi.ryusuke@gmail.com Subject: nilfs2: fix data corruption in dsync block recovery for small block sizes Date: Wed, 24 Jan 2024 21:19:36 +0900

The helper function nilfs_recovery_copy_block() of nilfs_recovery_dsync_blocks(), which recovers data from logs created by data sync writes during a mount after an unclean shutdown, incorrectly calculates the on-page offset when copying repair data to the file's page cache. In environments where the block size is smaller than the page size, this flaw can cause data corruption and leak uninitialized memory bytes during the recovery process.

Fix these issues by correcting this byte offset calculation on the page.

Link: https://lkml.kernel.org/r/20240124121936.10575-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/nilfs2/recovery.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/fs/nilfs2/recovery.c~nilfs2-fix-data-corruption-in-dsync-block-recovery-for-small-block-sizes +++ a/fs/nilfs2/recovery.c @@ -472,9 +472,10 @@ static int nilfs_prepare_segment_for_rec

static int nilfs_recovery_copy_block(struct the_nilfs *nilfs, struct nilfs_recovery_block *rb, - struct page *page) + loff_t pos, struct page *page) { struct buffer_head *bh_org; + size_t from = pos & ~PAGE_MASK; void *kaddr;

bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize); @@ -482,7 +483,7 @@ static int nilfs_recovery_copy_block(str return -EIO;

kaddr = kmap_atomic(page); - memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size); + memcpy(kaddr + from, bh_org->b_data, bh_org->b_size); kunmap_atomic(kaddr); brelse(bh_org); return 0; @@ -521,7 +522,7 @@ static int nilfs_recover_dsync_blocks(st goto failed_inode; }

- err = nilfs_recovery_copy_block(nilfs, rb, page); + err = nilfs_recovery_copy_block(nilfs, rb, pos, page); if (unlikely(err)) goto failed_page;

_

Patches currently in -mm which might be from konishi.ryusuke@gmail.com are

nilfs2-fix-data-corruption-in-dsync-block-recovery-for-small-block-sizes.patch nilfs2-convert-recovery-logic-to-use-kmap_local.patch nilfs2-convert-segment-buffer-to-use-kmap_local.patch nilfs2-convert-nilfs_copy_buffer-to-use-kmap_local.patch nilfs2-convert-metadata-file-common-code-to-use-kmap_local.patch nilfs2-convert-sufile-to-use-kmap_local.patch nilfs2-convert-persistent-object-allocator-to-use-kmap_local.patch nilfs2-convert-dat-to-use-kmap_local.patch nilfs2-move-nilfs_bmap_write-call-out-of-nilfs_write_inode_common.patch nilfs2-do-not-acquire-rwsem-in-nilfs_bmap_write.patch nilfs2-convert-ifile-to-use-kmap_local.patch nilfs2-localize-highmem-mapping-for-checkpoint-creation-within-cpfile.patch nilfs2-localize-highmem-mapping-for-checkpoint-finalization-within-cpfile.patch nilfs2-localize-highmem-mapping-for-checkpoint-reading-within-cpfile.patch nilfs2-remove-nilfs_cpfile_getput_checkpoint.patch nilfs2-convert-cpfile-to-use-kmap_local.patch