From: Ryusuke Konishi konishi.ryusuke@gmail.com

mainline inclusion from mainline-v6.12 commit 2026559a6c4ce34db117d2db8f710fe2a9420d5a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IB956M CVE: CVE-2024-53130

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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When using the "block:block_dirty_buffer" tracepoint, mark_buffer_dirty() may cause a NULL pointer dereference, or a general protection fault when KASAN is enabled.

This happens because, since the tracepoint was added in mark_buffer_dirty(), it references the dev_t member bh->b_bdev->bd_dev regardless of whether the buffer head has a pointer to a block_device structure.

In the current implementation, nilfs_grab_buffer(), which grabs a buffer to read (or create) a block of metadata, including b-tree node blocks, does not set the block device, but instead does so only if the buffer is not in the "uptodate" state for each of its caller block reading functions. However, if the uptodate flag is set on a folio/page, and the buffer heads are detached from it by try_to_free_buffers(), and new buffer heads are then attached by create_empty_buffers(), the uptodate flag may be restored to each buffer without the block device being set to bh->b_bdev, and mark_buffer_dirty() may be called later in that state, resulting in the bug mentioned above.

Fix this issue by making nilfs_grab_buffer() always set the block device of the super block structure to the buffer head, regardless of the state of the buffer's uptodate flag.

Link: https://lkml.kernel.org/r/20241106160811.3316-3-konishi.ryusuke@gmail.com Fixes: 5305cb830834 ("block: add block_{touch|dirty}_buffer tracepoint") Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: Tejun Heo tj@kernel.org Cc: Ubisectech Sirius bugreport@valiantsec.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org confilct: fs/nilfs2/page.c Signed-off-by: Yipeng Zou zouyipeng@huawei.com --- fs/nilfs2/btnode.c | 2 -- fs/nilfs2/gcinode.c | 4 +--- fs/nilfs2/mdt.c | 1 - fs/nilfs2/page.c | 1 + 4 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c index 28a726553318..1ced5bc551e4 100644 --- a/fs/nilfs2/btnode.c +++ b/fs/nilfs2/btnode.c @@ -68,7 +68,6 @@ nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr) goto failed; } memset(bh->b_data, 0, i_blocksize(inode)); - bh->b_bdev = inode->i_sb->s_bdev; bh->b_blocknr = blocknr; set_buffer_mapped(bh); set_buffer_uptodate(bh); @@ -133,7 +132,6 @@ int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr, goto found; } set_buffer_mapped(bh); - bh->b_bdev = inode->i_sb->s_bdev; bh->b_blocknr = pblocknr; /* set block address for read */ bh->b_end_io = end_buffer_read_sync; get_bh(bh); diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c index b0077f5f7112..518e10be1073 100644 --- a/fs/nilfs2/gcinode.c +++ b/fs/nilfs2/gcinode.c @@ -83,10 +83,8 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, goto out; }

- if (!buffer_mapped(bh)) { - bh->b_bdev = inode->i_sb->s_bdev; + if (!buffer_mapped(bh)) set_buffer_mapped(bh); - } bh->b_blocknr = pbn; bh->b_end_io = end_buffer_read_sync; get_bh(bh); diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c index e80ef2c0a785..c1f964916489 100644 --- a/fs/nilfs2/mdt.c +++ b/fs/nilfs2/mdt.c @@ -89,7 +89,6 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, if (buffer_uptodate(bh)) goto failed_bh;

- bh->b_bdev = sb->s_bdev; err = nilfs_mdt_insert_new_block(inode, block, bh, init_block); if (likely(!err)) { get_bh(bh); diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 7adf74b52550..80f1f371d729 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -64,6 +64,7 @@ struct buffer_head *nilfs_grab_buffer(struct inode *inode, put_page(page); return NULL; } + bh->b_bdev = inode->i_sb->s_bdev; return bh; }