ubifs: fix memory corruption in super.c

In list "super_blocks" ubifs collects allocated super_block
structs. U-Boot frees on unmount the allocated struct,
so the pointer stored in this list is free after the umount.
On a new ubifs mount, the new allocated super_block struct
get inserted into the super_blocks list ... which contains
now a freed pointer, and the list_add_tail() corrupts the
freed memory ...

2 solutions are possible:
- remove the super_block from the super_blocks list
  on umount

- as U-Boot does not use the super_blocks list ...
  remove it complete for U-Boot.

Both solutions should not introduce problems for porting
to newer linux version, so this patch removes the unused
super_blocks list, as it saves code size and execution
time.

Signed-off-by: Heiko Schocher <hs@denx.de>
This commit is contained in:
Heiko Schocher 2016-04-21 12:16:58 +02:00
parent 68fc449033
commit b1d6590d35

View File

@ -48,7 +48,6 @@ struct vfsmount;
#define INODE_LOCKED_MAX 64
struct super_block *ubifs_sb;
LIST_HEAD(super_blocks);
static struct inode *inodes_locked_down[INODE_LOCKED_MAX];
@ -2425,10 +2424,10 @@ retry:
s->s_type = type;
#ifndef __UBOOT__
strlcpy(s->s_id, type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
#else
strncpy(s->s_id, type->name, sizeof(s->s_id));
#endif
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &type->fs_supers);
#ifndef __UBOOT__
spin_unlock(&sb_lock);