The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x a9e1ddc09ca55746079cc479aa3eb6411f0d99d4 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024071540-widow-expansion-f3c5@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
a9e1ddc09ca5 ("nilfs2: fix kernel bug on rename operation of broken directory") 6f133c97e5ce ("nilfs2: convert nilfs_rename() to use folios") a4bf041e44d5 ("nilfs2: convert nilfs_find_entry to use a folio") 9b77f66f9927 ("nilfs2: switch to kmap_local for directory handling") 09a46acb3697 ("nilfs2: return the mapped address from nilfs_get_page()") 6af2191f8358 ("nilfs2: remove page_address() from nilfs_delete_entry") 6bb09fa1b44f ("nilfs2: remove page_address() from nilfs_set_link") 8cf57c6df818 ("nilfs2: eliminate staggered calls to kunmap in nilfs_rename") 584db20c181f ("nilfs2: move page release outside of nilfs_delete_entry and nilfs_set_link") b3e1cc3935ff ("nilfs2: convert to new timestamp accessors") e21d4f419402 ("nilfs2: convert to ctime accessor functions") 21a87d88c225 ("nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()") 79ea65563ad8 ("nilfs2: Remove check for PageError")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a9e1ddc09ca55746079cc479aa3eb6411f0d99d4 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi konishi.ryusuke@gmail.com Date: Sat, 29 Jun 2024 01:51:07 +0900 Subject: [PATCH] nilfs2: fix kernel bug on rename operation of broken directory
Syzbot reported that in rename directory operation on broken directory on nilfs2, __block_write_begin_int() called to prepare block write may fail BUG_ON check for access exceeding the folio/page size.
This is because nilfs_dotdot(), which gets parent directory reference entry ("..") of the directory to be moved or renamed, does not check consistency enough, and may return location exceeding folio/page size for broken directories.
Fix this issue by checking required directory entries ("." and "..") in the first chunk of the directory in nilfs_dotdot().
Link: https://lkml.kernel.org/r/20240628165107.9006-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+d3abed1ad3d367fa2627@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d3abed1ad3d367fa2627 Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index dddfa604491a..4a29b0138d75 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -383,11 +383,39 @@ struct nilfs_dir_entry *nilfs_find_entry(struct inode *dir,
struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct folio **foliop) { - struct nilfs_dir_entry *de = nilfs_get_folio(dir, 0, foliop); + struct folio *folio; + struct nilfs_dir_entry *de, *next_de; + size_t limit; + char *msg;
+ de = nilfs_get_folio(dir, 0, &folio); if (IS_ERR(de)) return NULL; - return nilfs_next_entry(de); + + limit = nilfs_last_byte(dir, 0); /* is a multiple of chunk size */ + if (unlikely(!limit || le64_to_cpu(de->inode) != dir->i_ino || + !nilfs_match(1, ".", de))) { + msg = "missing '.'"; + goto fail; + } + + next_de = nilfs_next_entry(de); + /* + * If "next_de" has not reached the end of the chunk, there is + * at least one more record. Check whether it matches "..". + */ + if (unlikely((char *)next_de == (char *)de + nilfs_chunk_size(dir) || + !nilfs_match(2, "..", next_de))) { + msg = "missing '..'"; + goto fail; + } + *foliop = folio; + return next_de; + +fail: + nilfs_error(dir->i_sb, "directory #%lu %s", dir->i_ino, msg); + folio_release_kmap(folio, de); + return NULL; }
ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)