From 75690493591fe283e4c92a3ba7c4420e9858abdb Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Sat, 23 Sep 2023 11:28:59 +0800 Subject: ubifs: ubifs_link: Fix wrong name len calculating when UBIFS is encrypted The length of dentry name is calculated after the raw name is encrypted, except for ubifs_link(), which could make the size of dir underflow. Here is a reproducer: touch $TMP/file mkdir $TMP/dir stat $TMP/dir for i in $(seq 1 8) do ln $TMP/file $TMP/dir/$i unlink $TMP/dir/$i done stat $TMP/dir The size of dir will be underflow(-96). Fix it by calculating dentry name's length after the name is encrypted. Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames") Reported-by: Roland Ruckerbauer Link: https://lore.kernel.org/linux-mtd/1638777819.2925845.1695222544742.JavaMail.zimbra@robart.cc/T/#u Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger --- fs/ubifs/dir.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'fs/ubifs') diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 2f48c58d47cd..5dc1ac4d826d 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -724,7 +724,7 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir, struct inode *inode = d_inode(old_dentry); struct ubifs_inode *ui = ubifs_inode(inode); struct ubifs_inode *dir_ui = ubifs_inode(dir); - int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len); + int err, sz_change; struct ubifs_budget_req req = { .new_dent = 1, .dirtied_ino = 2, .dirtied_ino_d = ALIGN(ui->data_len, 8) }; struct fscrypt_name nm; @@ -748,6 +748,8 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir, if (err) return err; + sz_change = CALC_DENT_SIZE(fname_len(&nm)); + err = dbg_check_synced_i_size(c, inode); if (err) goto out_fname; -- cgit v1.2.3