2022-02-06 22:48:12

by Ritesh Harjani

Subject: [PATCHv1 9/9] ext4: Add extra check in ext4_mb_mark_bb() to prevent against possible corruption

This patch adds an extra checks in ext4_mb_mark_bb() function
to make sure we mark & report error if we were to mark/clear any
of the critical FS metadata specific bitmaps (&bail out) to prevent
from any accidental corruption.

Suggested-by: Jan Kara <[email protected]>
Signed-off-by: Ritesh Harjani <[email protected]>
---
fs/ext4/mballoc.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9f2b3a057918..75c20a10529a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3918,6 +3918,14 @@ void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
clen = EXT4_NUM_B2C(sbi, thisgrp_len);

+ if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) {
+ ext4_error(sb, "Marking blocks in system zone - "
+ "Block = %llu, len = %u",
+ block, thisgrp_len);
+ bitmap_bh = NULL;
+ break;
+ }
+
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
--
2.31.1

2022-02-08 22:26:09

by Jan Kara

Subject: Re: [PATCHv1 9/9] ext4: Add extra check in ext4_mb_mark_bb() to prevent against possible corruption

On Sat 05-02-22 19:39:58, Ritesh Harjani wrote:
> This patch adds an extra checks in ext4_mb_mark_bb() function
> to make sure we mark & report error if we were to mark/clear any
> of the critical FS metadata specific bitmaps (&bail out) to prevent
> from any accidental corruption.
>
> Suggested-by: Jan Kara <[email protected]>
> Signed-off-by: Ritesh Harjani <[email protected]>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

Honza

> ---
> fs/ext4/mballoc.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 9f2b3a057918..75c20a10529a 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -3918,6 +3918,14 @@ void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
> EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
> clen = EXT4_NUM_B2C(sbi, thisgrp_len);
>
> + if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) {
> + ext4_error(sb, "Marking blocks in system zone - "
> + "Block = %llu, len = %u",
> + block, thisgrp_len);
> + bitmap_bh = NULL;
> + break;
> + }
> +
> bitmap_bh = ext4_read_block_bitmap(sb, group);
> if (IS_ERR(bitmap_bh)) {
> err = PTR_ERR(bitmap_bh);
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR