ACK/cmnt: [Zesty SRU][PATCH] f2fs: sanity check checkpoint segno and blkoff

[Kleber Souza]

On 09/28/2017 03:06 PM, Shrirang Bagul wrote:
> From: Jin Qian <jinqian at google.com>
>
> Make sure segno and blkoff read from raw image are valid.
>
> Cc: stable at vger.kernel.org
> Signed-off-by: Jin Qian <jinqian at google.com>
> [Jaegeuk Kim: adjust minor coding style]
> Signed-off-by: Jaegeuk Kim <jaegeuk at kernel.org>
>
> Fixes CVE-2017-10663

The above line should be:

CVE-2017-10663

It can be fixed when applying the patch.

>
> (cherry picked from commit 15d3042a937c13f5d9244241c7a9c8416ff6e82a)
> Signed-off-by: Shrirang Bagul <shrirang.bagul at canonical.com>

Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>

> ---
>  fs/f2fs/super.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 119b68332cd5..b876886eea2b 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1461,6 +1461,8 @@ int sanity_check_ckpt(struct f2fs_sb_info *sbi)
>  	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
>  	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
>  	unsigned int ovp_segments, reserved_segments;
> +	unsigned int main_segs, blocks_per_seg;
> +	int i;
>
>  	total = le32_to_cpu(raw_super->segment_count);
>  	fsmeta = le32_to_cpu(raw_super->segment_count_ckpt);
> @@ -1482,6 +1484,20 @@ int sanity_check_ckpt(struct f2fs_sb_info *sbi)
>  		return 1;
>  	}
>
> +	main_segs = le32_to_cpu(raw_super->segment_count_main);
> +	blocks_per_seg = sbi->blocks_per_seg;
> +
> +	for (i = 0; i < NR_CURSEG_NODE_TYPE; i++) {
> +		if (le32_to_cpu(ckpt->cur_node_segno[i]) >= main_segs ||
> +			le16_to_cpu(ckpt->cur_node_blkoff[i]) >= blocks_per_seg)
> +			return 1;
> +	}
> +	for (i = 0; i < NR_CURSEG_DATA_TYPE; i++) {
> +		if (le32_to_cpu(ckpt->cur_data_segno[i]) >= main_segs ||
> +			le16_to_cpu(ckpt->cur_data_blkoff[i]) >= blocks_per_seg)
> +			return 1;
> +	}
> +
>  	if (unlikely(f2fs_cp_error(sbi))) {
>  		f2fs_msg(sbi->sb, KERN_ERR, "A bug case: need to run fsck");
>  		return 1;
>