From: Zhihao Cheng chengzhihao1@huawei.com
commit 40a8f0d5e7b3999f096570edab71c345da812e3e upstream.
'whiteout_ui->data' will be freed twice if space budget fail for rename whiteout operation as following process:
rename_whiteout dev = kmalloc whiteout_ui->data = dev kfree(whiteout_ui->data) // Free first time iput(whiteout) ubifs_free_inode kfree(ui->data) // Double free!
KASAN reports: ================================================================== BUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70 Call Trace: kfree+0x117/0x490 ubifs_free_inode+0x4f/0x70 [ubifs] i_callback+0x30/0x60 rcu_do_batch+0x366/0xac0 __do_softirq+0x133/0x57f
Allocated by task 1506: kmem_cache_alloc_trace+0x3c2/0x7a0 do_rename+0x9b7/0x1150 [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80
Freed by task 1506: kfree+0x117/0x490 do_rename.cold+0x53/0x8a [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80
The buggy address belongs to the object at ffff88810238bed8 which belongs to the cache kmalloc-8 of size 8 ==================================================================
Let ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused assignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode() -> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it (because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release', and the nlink of whiteout inode is 0).
Fixes: 9e0a1fff8db56ea ("ubifs: Implement RENAME_WHITEOUT") Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ubifs/dir.c | 2 -- 1 file changed, 2 deletions(-)
--- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -1425,8 +1425,6 @@ static int do_rename(struct inode *old_d
err = ubifs_budget_space(c, &wht_req); if (err) { - kfree(whiteout_ui->data); - whiteout_ui->data_len = 0; iput(whiteout); goto out_release; }