Messages in this thread Patch in this message | | | From | Dongliang Mu <> | Subject | [PATCH v2] fs: fix UAF/GPF bug in nilfs_mdt_destroy | Date | Tue, 16 Aug 2022 12:08:58 +0800 |
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From: Dongliang Mu <mudongliangabcd@gmail.com>
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 <butterflyhuangxx@gmail.com> Reported-by: Hao Sun <sunhao.th@gmail.com> Reported-by: Jiacheng Xu <stitch@zju.edu.cn> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org --- v1->v2: move security_inode_alloc at the very end according to Al Viro other than initializing i_private before security_inode_alloc. fs/inode.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c index 6462276dfdf0..49d1eb91728c 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); @@ -228,6 +226,9 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_fsnotify_mask = 0; #endif inode->i_flctx = NULL; + + if (security_inode_alloc(inode)) + goto out; this_cpu_inc(nr_inodes); return 0; -- 2.35.1
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