iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ext4: fix possible use-after-free in ext4_remove_li_request()

Browse Source 
We need to take reference to the s_li_request after we take a mutex,
because it might be freed since then, hence result in accessing old
already freed memory. Also we should protect the whole
ext4_remove_li_request() because ext4_li_info might be in the process of
being freed in ext4_lazyinit_thread().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
This commit is contained in:
Lukas Czerner 2011-05-20 13:55:29 -04:00 committed by Theodore Ts'o
parent 51ce651156
commit 1bb933fb1f
1 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
fs/ext4/super.c
View File

@ -2735,14 +2735,16 @@ static void ext4_remove_li_request(struct ext4_li_request *elr)
static void ext4_unregister_li_request(struct super_block *sb)
{
struct ext4_li_request *elr = EXT4_SB(sb)->s_li_request;
if (!ext4_li_info)
mutex_lock(&ext4_li_mtx);
if (!ext4_li_info) {
mutex_unlock(&ext4_li_mtx);
return;
}
mutex_lock(&ext4_li_info->li_list_mtx);
ext4_remove_li_request(elr);
ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
mutex_unlock(&ext4_li_info->li_list_mtx);
mutex_unlock(&ext4_li_mtx);
}
static struct task_struct *ext4_lazyinit_task;