From 2a96b532098284ecf8e4849b8b9e5fc7a28bdee9 Mon Sep 17 00:00:00 2001 From: Dongliang Mu Date: Tue, 16 Aug 2022 12:08:58 +0800 Subject: [PATCH] fs: fix UAF/GPF bug in nilfs_mdt_destroy MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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@mail.gmail.com Reported-by: butt3rflyh4ck Reported-by: Hao Sun Reported-by: Jiacheng Xu Reviewed-by: Christian Brauner (Microsoft) Signed-off-by: Dongliang Mu Cc: Al Viro Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/inode.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index ba1de23c13c1ed..b608528efd3a46 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -192,8 +192,6 @@ int inode_init_always(struct super_block *sb, struct inode *inode) 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 *sb, struct inode *inode) 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);