From: Rustam Subkhankulov <subkhankulov@xxxxxxxxx>
If function 'security_inode_alloc()' returns a nonzero value at
[fs/inode.c: 195] due to an error (e.g. fail to allocate memory),
then some of the fields, including 'i_private', will not be
initialized.
After that, if the fs-specfic free_inode function is called in
'i_callback', the nonzero value of 'i_private' field can be interpreted
as initialized. As a result, this can cause dereferencing of random
value pointer (e.g. nilfs2).
In earlier versions, a similar situation could occur with the 'u' union
in 'inode' structure.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Signed-off-by: Rustam Subkhankulov <subkhankulov@xxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
---
fs/inode.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index bd4da9c5207e..08d093737e8c 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);
@@ -230,9 +228,10 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_flctx = NULL;
this_cpu_inc(nr_inodes);
+ if (security_inode_alloc(inode))
+ return -ENOMEM;
+
return 0;
-out:
- return -ENOMEM;
}
EXPORT_SYMBOL(inode_init_always);
--
2.34.1
