queue-4.19/btrfs-prop-fix-zstd-compression-parameter-validation.patch

   1 From 50398fde997f6be8faebdb5f38e9c9c467370f51 Mon Sep 17 00:00:00 2001
   2 From: Anand Jain <anand.jain@oracle.com>
   3 Date: Tue, 2 Apr 2019 18:07:38 +0800
   4 Subject: btrfs: prop: fix zstd compression parameter validation
   5
   6 From: Anand Jain <anand.jain@oracle.com>
   7
   8 commit 50398fde997f6be8faebdb5f38e9c9c467370f51 upstream.
   9
  10 We let pass zstd compression parameter even if it is not fully valid.
  11 For example:
  12
  13   $ btrfs prop set /btrfs compression zst
  14   $ btrfs prop get /btrfs compression
  15      compression=zst
  16
  17 zlib and lzo are fine.
  18
  19 Fix it by checking the correct prefix length.
  20
  21 Fixes: 5c1aab1dd544 ("btrfs: Add zstd support")
  22 CC: stable@vger.kernel.org # 4.14+
  23 Reviewed-by: Nikolay Borisov <nborisov@suse.com>
  24 Signed-off-by: Anand Jain <anand.jain@oracle.com>
  25 Reviewed-by: David Sterba <dsterba@suse.com>
  26 Signed-off-by: David Sterba <dsterba@suse.com>
  27 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  28
  29 ---
  30  fs/btrfs/props.c |    2 +-
  31  1 file changed, 1 insertion(+), 1 deletion(-)
  32
  33 --- a/fs/btrfs/props.c
  34 +++ b/fs/btrfs/props.c
  35 @@ -396,7 +396,7 @@ static int prop_compression_apply(struct
  36                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
  37         } else if (!strncmp("zlib", value, 4)) {
  38                 type = BTRFS_COMPRESS_ZLIB;
  39 -       } else if (!strncmp("zstd", value, len)) {
  40 +       } else if (!strncmp("zstd", value, 4)) {
  41                 type = BTRFS_COMPRESS_ZSTD;
  42                 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
  43         } else {