From f37c563bab4297024c300b05c8f48430e323809d Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Fri Jul 10 09:49:56 2020 +0200
Subject: [PATCH] btrfs: add missing check for nocow and compression inode flags
Git-commit: f37c563bab4297024c300b05c8f48430e323809d
References: bsc#1178780
Patch-mainline: v5.9-rc1
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>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b4ddf51..bd3511c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -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