From: Dongliang Mu <mudongliangabcd@xxxxxxxxx> commit 2e488f13755ffbb60f307e991b27024716a33b29 upstream. In alloc_inode, inode_init_always() could return -ENOMEM if security_inode_alloc() fails, which causes inode->i_private uninitialized. Then nilfs_is_metadata_file_inode() returns true and nilfs_free_inode() wrongly calls nilfs_mdt_destroy(), which frees the uninitialized inode->i_private and leads to crashes(e.g., UAF/GPF). Fix this by moving security_inode_alloc just prior to this_cpu_inc(nr_inodes) Link: https://lkml.kernel.org/r/CAFcO6XOcf1Jj2SeGt=jJV59wmhESeSKpfR0omdFRq+J9nD1vfQ@xxxxxxxxxxxxxx Reported-by: butt3rflyh4ck <butterflyhuangxx@xxxxxxxxx> Reported-by: Hao Sun <sunhao.th@xxxxxxxxx> Reported-by: Jiacheng Xu <stitch@xxxxxxxxxx> Reviewed-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx> Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/inode.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/fs/inode.c +++ b/fs/inode.c @@ -192,8 +192,6 @@ int inode_init_always(struct super_block inode->i_wb_frn_history = 0; #endif - if (security_inode_alloc(inode)) - goto out; spin_lock_init(&inode->i_lock); lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); @@ -228,11 +226,12 @@ int inode_init_always(struct super_block inode->i_fsnotify_mask = 0; #endif inode->i_flctx = NULL; + + if (unlikely(security_inode_alloc(inode))) + return -ENOMEM; this_cpu_inc(nr_inodes); return 0; -out: - return -ENOMEM; } EXPORT_SYMBOL(inode_init_always);
