commit 08cfa12adf888db98879dbd735bc741360a34168 upstream.
Syzbot reported that a task hang occurs in vcs_open() during a fuzzing test for nilfs2.
The root cause of this problem is that in nilfs_find_entry(), which searches for directory entries, ignores errors when loading a directory page/folio via nilfs_get_folio() fails.
If the filesystem images is corrupted, and the i_size of the directory inode is large, and the directory page/folio is successfully read but fails the sanity check, for example when it is zero-filled, nilfs_check_folio() may continue to spit out error messages in bursts.
Fix this issue by propagating the error to the callers when loading a page/folio fails in nilfs_find_entry().
The current interface of nilfs_find_entry() and its callers is outdated and cannot propagate error codes such as -EIO and -ENOMEM returned via nilfs_find_entry(), so fix it together.
Link: https://lkml.kernel.org/r/20241004033640.6841-1-konishi.ryusuke@gmail.com Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: Lizhi Xu lizhi.xu@windriver.com Closes: https://lkml.kernel.org/r/20240927013806.3577931-1-lizhi.xu@windriver.com Reported-by: syzbot+8a192e8d090fa9a31135@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=8a192e8d090fa9a31135 Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org --- Please apply this patch to the 6.6-stable instead of the failed patch.
This patch is tailored to take page/folio conversion into account. Compiled and tested successfully.
Thanks, Ryusuke Konishi
fs/nilfs2/dir.c | 50 +++++++++++++++++++++++++---------------------- fs/nilfs2/namei.c | 39 ++++++++++++++++++++++++------------ fs/nilfs2/nilfs.h | 2 +- 3 files changed, 54 insertions(+), 37 deletions(-)
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index 53e4e63c607e..ddf8e575e489 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -331,6 +331,8 @@ static int nilfs_readdir(struct file *file, struct dir_context *ctx) * returns the page in which the entry was found, and the entry itself * (as a parameter - res_dir). Page is returned mapped and unlocked. * Entry is guaranteed to be valid. + * + * On failure, returns an error pointer and the caller should ignore res_page. */ struct nilfs_dir_entry * nilfs_find_entry(struct inode *dir, const struct qstr *qstr, @@ -358,22 +360,24 @@ nilfs_find_entry(struct inode *dir, const struct qstr *qstr, do { char *kaddr = nilfs_get_page(dir, n, &page);
- if (!IS_ERR(kaddr)) { - de = (struct nilfs_dir_entry *)kaddr; - kaddr += nilfs_last_byte(dir, n) - reclen; - while ((char *) de <= kaddr) { - if (de->rec_len == 0) { - nilfs_error(dir->i_sb, - "zero-length directory entry"); - nilfs_put_page(page); - goto out; - } - if (nilfs_match(namelen, name, de)) - goto found; - de = nilfs_next_entry(de); + if (IS_ERR(kaddr)) + return ERR_CAST(kaddr); + + de = (struct nilfs_dir_entry *)kaddr; + kaddr += nilfs_last_byte(dir, n) - reclen; + while ((char *)de <= kaddr) { + if (de->rec_len == 0) { + nilfs_error(dir->i_sb, + "zero-length directory entry"); + nilfs_put_page(page); + goto out; } - nilfs_put_page(page); + if (nilfs_match(namelen, name, de)) + goto found; + de = nilfs_next_entry(de); } + nilfs_put_page(page); + if (++n >= npages) n = 0; /* next page is past the blocks we've got */ @@ -386,7 +390,7 @@ nilfs_find_entry(struct inode *dir, const struct qstr *qstr, } } while (n != start); out: - return NULL; + return ERR_PTR(-ENOENT);
found: *res_page = page; @@ -431,19 +435,19 @@ struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p) return NULL; }
-ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr) +int nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr, ino_t *ino) { - ino_t res = 0; struct nilfs_dir_entry *de; struct page *page;
de = nilfs_find_entry(dir, qstr, &page); - if (de) { - res = le64_to_cpu(de->inode); - kunmap(page); - put_page(page); - } - return res; + if (IS_ERR(de)) + return PTR_ERR(de); + + *ino = le64_to_cpu(de->inode); + kunmap(page); + put_page(page); + return 0; }
/* Releases the page */ diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c index 2a4e7f4a8102..9f9b0762ff69 100644 --- a/fs/nilfs2/namei.c +++ b/fs/nilfs2/namei.c @@ -55,12 +55,20 @@ nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { struct inode *inode; ino_t ino; + int res;
if (dentry->d_name.len > NILFS_NAME_LEN) return ERR_PTR(-ENAMETOOLONG);
- ino = nilfs_inode_by_name(dir, &dentry->d_name); - inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL; + res = nilfs_inode_by_name(dir, &dentry->d_name, &ino); + if (res) { + if (res != -ENOENT) + return ERR_PTR(res); + inode = NULL; + } else { + inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino); + } + return d_splice_alias(inode, dentry); }
@@ -263,10 +271,11 @@ static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry) struct page *page; int err;
- err = -ENOENT; de = nilfs_find_entry(dir, &dentry->d_name, &page); - if (!de) + if (IS_ERR(de)) { + err = PTR_ERR(de); goto out; + }
inode = d_inode(dentry); err = -EIO; @@ -361,10 +370,11 @@ static int nilfs_rename(struct mnt_idmap *idmap, if (unlikely(err)) return err;
- err = -ENOENT; old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page); - if (!old_de) + if (IS_ERR(old_de)) { + err = PTR_ERR(old_de); goto out; + }
if (S_ISDIR(old_inode->i_mode)) { err = -EIO; @@ -381,10 +391,12 @@ static int nilfs_rename(struct mnt_idmap *idmap, if (dir_de && !nilfs_empty_dir(new_inode)) goto out_dir;
- err = -ENOENT; - new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page); - if (!new_de) + new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, + &new_page); + if (IS_ERR(new_de)) { + err = PTR_ERR(new_de); goto out_dir; + } nilfs_set_link(new_dir, new_de, new_page, old_inode); nilfs_mark_inode_dirty(new_dir); inode_set_ctime_current(new_inode); @@ -438,13 +450,14 @@ static int nilfs_rename(struct mnt_idmap *idmap, */ static struct dentry *nilfs_get_parent(struct dentry *child) { - unsigned long ino; + ino_t ino; + int res; struct inode *inode; struct nilfs_root *root;
- ino = nilfs_inode_by_name(d_inode(child), &dotdot_name); - if (!ino) - return ERR_PTR(-ENOENT); + res = nilfs_inode_by_name(d_inode(child), &dotdot_name, &ino); + if (res) + return ERR_PTR(res);
root = NILFS_I(d_inode(child))->i_root;
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h index 9a157e5051d0..ad13e74af65f 100644 --- a/fs/nilfs2/nilfs.h +++ b/fs/nilfs2/nilfs.h @@ -233,7 +233,7 @@ static inline __u32 nilfs_mask_flags(umode_t mode, __u32 flags)
/* dir.c */ extern int nilfs_add_link(struct dentry *, struct inode *); -extern ino_t nilfs_inode_by_name(struct inode *, const struct qstr *); +int nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr, ino_t *ino); extern int nilfs_make_empty(struct inode *, struct inode *); extern struct nilfs_dir_entry * nilfs_find_entry(struct inode *, const struct qstr *, struct page **);