From d3995ff08c15a6a0f659a253b9e883ff890cb12a Mon Sep 17 00:00:00 2001 From: Johannes Kimmel Date: Wed, 19 Mar 2025 22:49:00 +0100 Subject: [PATCH] btrfs: correctly escape subvol in btrfs_show_options() commit dc08c58696f8555e4a802f1f23c894a330d80ab7 upstream. Currently, displaying the btrfs subvol mount option doesn't escape ','. This makes parsing /proc/self/mounts and /proc/self/mountinfo ambiguous for subvolume names that contain commas. The text after the comma could be mistaken for another option (think "subvol=foo,ro", where ro is actually part of the subvolumes name). Replace the manual escape characters list with a call to seq_show_option(). Thanks to Calvin Walton for suggesting this approach. Fixes: c8d3fe028f64 ("Btrfs: show subvol= and subvolid= in /proc/mounts") CC: stable@vger.kernel.org # 5.4+ Suggested-by: Calvin Walton Signed-off-by: Johannes Kimmel Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/super.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 73343503ea60..08ccf5d5e144 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1140,8 +1140,7 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) subvol_name = btrfs_get_subvol_name_from_objectid(info, btrfs_root_id(BTRFS_I(d_inode(dentry))->root)); if (!IS_ERR(subvol_name)) { - seq_puts(seq, ",subvol="); - seq_escape(seq, subvol_name, " \t\n\\"); + seq_show_option(seq, "subvol", subvol_name); kfree(subvol_name); } return 0;