btrfs: verify subvolid mount parameter (ccb0e7d1) · Commits · 戴 / test

We aren't verifying the parameter passed to the subvolid mount option, so we won't report and fail the mount if a junk value is specified for example, -o subvolid=abc. This patch verifies the subvolid option with match_u64. Up to now the memparse function accepts the K/M/G/ suffixes, that are usually meant for size values and do not make sense for a subvolume it. Signed-off-by:

Anand Jain <anand.jain@oracle.com> Reviewed-by:

David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by:

David Sterba <dsterba@suse.com>

fs/btrfs/super.c

+9 −12

Original line number	Diff line number	Diff line
		@@ -914,8 +914,8 @@ static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
		{
		substring_t args[MAX_OPT_ARGS];
		char opts, orig, *p;
		char *num = NULL;
		int error = 0;
		u64 subvolid;

		if (!options)
		return 0;
		@@ -945,18 +945,15 @@ static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
		}
		break;
		case Opt_subvolid:
		num = match_strdup(&args[0]);
		if (num) {
		*subvol_objectid = memparse(num, NULL);
		kfree(num);
		/* we want the original fs_tree */
		if (!*subvol_objectid)
		*subvol_objectid =
		BTRFS_FS_TREE_OBJECTID;
		} else {
		error = -EINVAL;
		error = match_u64(&args[0], &subvolid);
		if (error)
		goto out;
		}

		/* we want the original fs_tree */
		if (subvolid == 0)
		subvolid = BTRFS_FS_TREE_OBJECTID;

		*subvol_objectid = subvolid;
		break;
		case Opt_subvolrootid:
		pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");

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