forked from luck/tmp_suning_uos_patched
ovl: check the capability before cred overridden
We found that it return success when we set IMMUTABLE_FL flag to a file in docker even though the docker didn't have the capability CAP_LINUX_IMMUTABLE. The commitd1d04ef857
("ovl: stack file ops") anddab5ca8fd9
("ovl: add lsattr/chattr support") implemented chattr operations on a regular overlay file. ovl_real_ioctl() overridden the current process's subjective credentials with ofs->creator_cred which have the capability CAP_LINUX_IMMUTABLE so that it will return success in vfs_ioctl()->cap_capable(). Fix this by checking the capability before cred overridden. And here we only care about APPEND_FL and IMMUTABLE_FL, so get these information from inode. [SzM: move check and call to underlying fs inside inode locked region to prevent two such calls from racing with each other] Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
parent
d989903058
commit
98487de318
|
@ -11,6 +11,7 @@
|
|||
#include <linux/mount.h>
|
||||
#include <linux/xattr.h>
|
||||
#include <linux/uio.h>
|
||||
#include <linux/uaccess.h>
|
||||
#include "overlayfs.h"
|
||||
|
||||
static char ovl_whatisit(struct inode *inode, struct inode *realinode)
|
||||
|
@ -408,10 +409,68 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
|
|||
return ret;
|
||||
}
|
||||
|
||||
static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
||||
static unsigned int ovl_get_inode_flags(struct inode *inode)
|
||||
{
|
||||
unsigned int flags = READ_ONCE(inode->i_flags);
|
||||
unsigned int ovl_iflags = 0;
|
||||
|
||||
if (flags & S_SYNC)
|
||||
ovl_iflags |= FS_SYNC_FL;
|
||||
if (flags & S_APPEND)
|
||||
ovl_iflags |= FS_APPEND_FL;
|
||||
if (flags & S_IMMUTABLE)
|
||||
ovl_iflags |= FS_IMMUTABLE_FL;
|
||||
if (flags & S_NOATIME)
|
||||
ovl_iflags |= FS_NOATIME_FL;
|
||||
|
||||
return ovl_iflags;
|
||||
}
|
||||
|
||||
static long ovl_ioctl_set_flags(struct file *file, unsigned long arg)
|
||||
{
|
||||
long ret;
|
||||
struct inode *inode = file_inode(file);
|
||||
unsigned int flags;
|
||||
unsigned int old_flags;
|
||||
|
||||
if (!inode_owner_or_capable(inode))
|
||||
return -EACCES;
|
||||
|
||||
if (get_user(flags, (int __user *) arg))
|
||||
return -EFAULT;
|
||||
|
||||
ret = mnt_want_write_file(file);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
inode_lock(inode);
|
||||
|
||||
/* Check the capability before cred override */
|
||||
ret = -EPERM;
|
||||
old_flags = ovl_get_inode_flags(inode);
|
||||
if (((flags ^ old_flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&
|
||||
!capable(CAP_LINUX_IMMUTABLE))
|
||||
goto unlock;
|
||||
|
||||
ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
|
||||
if (ret)
|
||||
goto unlock;
|
||||
|
||||
ret = ovl_real_ioctl(file, FS_IOC_SETFLAGS, arg);
|
||||
|
||||
ovl_copyflags(ovl_inode_real(inode), inode);
|
||||
unlock:
|
||||
inode_unlock(inode);
|
||||
|
||||
mnt_drop_write_file(file);
|
||||
|
||||
return ret;
|
||||
|
||||
}
|
||||
|
||||
static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
||||
{
|
||||
long ret;
|
||||
|
||||
switch (cmd) {
|
||||
case FS_IOC_GETFLAGS:
|
||||
|
@ -419,23 +478,7 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|||
break;
|
||||
|
||||
case FS_IOC_SETFLAGS:
|
||||
if (!inode_owner_or_capable(inode))
|
||||
return -EACCES;
|
||||
|
||||
ret = mnt_want_write_file(file);
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
|
||||
if (!ret) {
|
||||
ret = ovl_real_ioctl(file, cmd, arg);
|
||||
|
||||
inode_lock(inode);
|
||||
ovl_copyflags(ovl_inode_real(inode), inode);
|
||||
inode_unlock(inode);
|
||||
}
|
||||
|
||||
mnt_drop_write_file(file);
|
||||
ret = ovl_ioctl_set_flags(file, arg);
|
||||
break;
|
||||
|
||||
default:
|
||||
|
|
Loading…
Reference in New Issue
Block a user