redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

ovl: check lowerdir amount for non-upper mount 

Recently multi-lower layer mount support allow upperdir and workdir
to be omitted, then cause overlayfs can be mount with only one
lowerdir directory. This action make no sense and have potential risk.

This patch check the total number of lower directories to prevent
mounting overlayfs with only one directory.

Also, an error message is added to indicate lower directories exceed
OVL_MAX_STACK limit.

Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
hifive-unleashed-5.1
hujianyang 2015-01-15 13:19:21 +08:00 committed by Miklos Szeredi
parent bead55ef77
commit 6be4506e34
1 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
fs/overlayfs/super.c
View File

@ -870,8 +870,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
err = -EINVAL;
stacklen = ovl_split_lowerdirs(lowertmp);
if (stacklen > OVL_MAX_STACK)
if (stacklen > OVL_MAX_STACK) {
pr_err("overlayfs: too many lower directries, limit is %d\n",
OVL_MAX_STACK);
goto out_free_lowertmp;
} else if (!ufs->config.upperdir && stacklen == 1) {
pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
goto out_free_lowertmp;
}
stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
if (!stack)