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platform_kernel-5.15
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ovl: use generic vfs_ioc_setflags_prepare() helper 

Canonalize to ioctl FS_* flags instead of inode S_* flags.

Note that we do not call the helper vfs_ioc_fssetxattr_check()
for FS_IOC_FSSETXATTR ioctl. The reason is that underlying filesystem
will perform all the checks. We only need to perform the capability
check before overriding credentials.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2020-09-29 15:28:48 +08:00 committed by Miklos Szeredi
parent 61536bed21
commit be4df0cea0
1 changed files with 30 additions and 32 deletions
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62
fs/overlayfs/file.c
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@ -559,12 +559,28 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
return ret; return ret;
} }
static unsigned int ovl_iflags_to_fsflags(unsigned int iflags)
{
unsigned int flags = 0;
if (iflags & S_SYNC)
flags |= FS_SYNC_FL;
if (iflags & S_APPEND)
flags |= FS_APPEND_FL;
if (iflags & S_IMMUTABLE)
flags |= FS_IMMUTABLE_FL;
if (iflags & S_NOATIME)
flags |= FS_NOATIME_FL;
return flags;
}
static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd, static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
unsigned long arg, unsigned int iflags) unsigned long arg, unsigned int flags)
{ {
long ret; long ret;
struct inode *inode = file_inode(file); struct inode *inode = file_inode(file);
unsigned int old_iflags; unsigned int oldflags;
if (!inode_owner_or_capable(inode)) if (!inode_owner_or_capable(inode))
return -EACCES; return -EACCES;
@ -576,10 +592,9 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
inode_lock(inode); inode_lock(inode);
/* Check the capability before cred override */ /* Check the capability before cred override */
ret = -EPERM; oldflags = ovl_iflags_to_fsflags(READ_ONCE(inode->i_flags));
old_iflags = READ_ONCE(inode->i_flags); ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) && if (ret)
!capable(CAP_LINUX_IMMUTABLE))
goto unlock; goto unlock;
ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY); ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
@ -598,22 +613,6 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
} }
static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
{
unsigned int iflags = 0;
if (flags & FS_SYNC_FL)
iflags |= S_SYNC;
if (flags & FS_APPEND_FL)
iflags |= S_APPEND;
if (flags & FS_IMMUTABLE_FL)
iflags |= S_IMMUTABLE;
if (flags & FS_NOATIME_FL)
iflags |= S_NOATIME;
return iflags;
}
static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd, static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
unsigned long arg) unsigned long arg)
{ {
@ -622,24 +621,23 @@ static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
if (get_user(flags, (int __user *) arg)) if (get_user(flags, (int __user *) arg))
return -EFAULT; return -EFAULT;
return ovl_ioctl_set_flags(file, cmd, arg, return ovl_ioctl_set_flags(file, cmd, arg, flags);
ovl_fsflags_to_iflags(flags));
} }
static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags) static unsigned int ovl_fsxflags_to_fsflags(unsigned int xflags)
{ {
unsigned int iflags = 0; unsigned int flags = 0;
if (xflags & FS_XFLAG_SYNC) if (xflags & FS_XFLAG_SYNC)
iflags |= S_SYNC; flags |= FS_SYNC_FL;
if (xflags & FS_XFLAG_APPEND) if (xflags & FS_XFLAG_APPEND)
iflags |= S_APPEND; flags |= FS_APPEND_FL;
if (xflags & FS_XFLAG_IMMUTABLE) if (xflags & FS_XFLAG_IMMUTABLE)
iflags |= S_IMMUTABLE; flags |= FS_IMMUTABLE_FL;
if (xflags & FS_XFLAG_NOATIME) if (xflags & FS_XFLAG_NOATIME)
iflags |= S_NOATIME; flags |= FS_NOATIME_FL;
return iflags; return flags;
} }
static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd, static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
@ -652,7 +650,7 @@ static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
return -EFAULT; return -EFAULT;
return ovl_ioctl_set_flags(file, cmd, arg, return ovl_ioctl_set_flags(file, cmd, arg,
ovl_fsxflags_to_iflags(fa.fsx_xflags)); ovl_fsxflags_to_fsflags(fa.fsx_xflags));
} }
long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg) long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)