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btrfs: add missing check for nocow and compression inode flags

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User Forza reported on IRC that some invalid combinations of file
attributes are accepted by chattr.

The NODATACOW and compression file flags/attributes are mutually
exclusive, but they could be set by 'chattr +c +C' on an empty file. The
nodatacow will be in effect because it's checked first in
btrfs_run_delalloc_range.

Extend the flag validation to catch the following cases:

  - input flags are conflicting
  - old and new flags are conflicting
  - initialize the local variable with inode flags after inode ls locked

Inode attributes take precedence over mount options and are an
independent setting.

Nocompress would be a no-op with nodatacow, but we don't want to mix
any compression-related options with nodatacow.

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2020-07-10 09:49:56 +02:00
parent 4faf55b038
commit f37c563bab
1 changed files with 22 additions and 8 deletions
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30
fs/btrfs/ioctl.c
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@ -164,8 +164,11 @@ static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
return 0;
}
/* Check if @flags are a supported and valid set of FS_*_FL flags */
static int check_fsflags(unsigned int flags)
/*
* Check if @flags are a supported and valid set of FS_*_FL flags and that
* the old and new flags are not conflicting
*/
static int check_fsflags(unsigned int old_flags, unsigned int flags)
{
if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
FS_NOATIME_FL | FS_NODUMP_FL | \
@ -174,9 +177,19 @@ static int check_fsflags(unsigned int flags)
FS_NOCOW_FL))
return -EOPNOTSUPP;
/* COMPR and NOCOMP on new/old are valid */
if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
return -EINVAL;
if ((flags & FS_COMPR_FL) && (flags & FS_NOCOW_FL))
return -EINVAL;
/* NOCOW and compression options are mutually exclusive */
if ((old_flags & FS_NOCOW_FL) && (flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
return -EINVAL;
if ((flags & FS_NOCOW_FL) && (old_flags & (FS_COMPR_FL | FS_NOCOMP_FL)))
return -EINVAL;
return 0;
}
@ -190,7 +203,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
unsigned int fsflags, old_fsflags;
int ret;
const char *comp = NULL;
u32 binode_flags = binode->flags;
u32 binode_flags;
if (!inode_owner_or_capable(inode))
return -EPERM;
@ -201,22 +214,23 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
if (copy_from_user(&fsflags, arg, sizeof(fsflags)))
return -EFAULT;
ret = check_fsflags(fsflags);
if (ret)
return ret;
ret = mnt_want_write_file(file);
if (ret)
return ret;
inode_lock(inode);
fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
if (ret)
goto out_unlock;
ret = check_fsflags(old_fsflags, fsflags);
if (ret)
goto out_unlock;
binode_flags = binode->flags;
if (fsflags & FS_SYNC_FL)
binode_flags |= BTRFS_INODE_SYNC;
else