linux-ext4 - Re: [RFC PATCH 1/8] e2fsck Fix access after free for dx

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Message-Id: <C4A81921-AC45-4E77-A0D9-16241A2AD14E@dilger.ca>
Date:   Sat, 28 Oct 2017 00:05:30 -0600
From:   Andreas Dilger <adilger@...ger.ca>
To:     Artem Blagodarenko <artem.blagodarenko@...il.com>
Cc:     linux-ext4 <linux-ext4@...r.kernel.org>,
        Alexey Lyashkov <alexey.lyashkov@...il.com>
Subject: Re: [RFC PATCH 1/8] e2fsck Fix access after free for dx_db structure

On Oct 27, 2017, at 11:22 AM, Artem Blagodarenko <artem.blagodarenko@...il.com> wrote:
> 
> dx_db structure is freed after fixing of PR_2_HTREE_BAD_ROOT
> problem. Next code block use this structure to unerstand if leaf
> is beeng processed.
> 
> if dx_db is freed then root block is beendg processad and if_leaf
> need to be set to 0.

This looks like a generic bugfix and should probably be submitted
separately?

Cheers, Andreas

> Signed-off-by: Artem Blagodarenko <artem.blagodarenko@...il.com>
> ---
> e2fsck/pass2.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
> index 09b79c3b..f3b49ec8 100644
> --- a/e2fsck/pass2.c
> +++ b/e2fsck/pass2.c
> @@ -1109,7 +1109,7 @@ inline_read_fail:
> 			    ((fs->blocksize - (8 + dx_csum_size)) /
> 			     sizeof(struct ext2_dx_entry))))
> 			dx_db->type = DX_DIRBLOCK_NODE;
> -		is_leaf = (dx_db->type == DX_DIRBLOCK_LEAF);
> +		is_leaf = dx_db ? (dx_db->type == DX_DIRBLOCK_LEAF) : 0;
> 	}
> out_htree:
> 
> --
> 2.13.5 (Apple Git-94)
> 







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