ACK: [Trusty SRU][PATCH 1/1] f2fs: do more integrity verification for superblock

[Colin Ian King]

On 28/11/17 09:09, Kleber Sacilotto de Souza wrote:
> From: Chao Yu <chao2.yu at samsung.com>
> 
> CVE-2017-0750
> 
> Do more sanity check for superblock during ->mount.
> 
> Signed-off-by: Chao Yu <chao2.yu at samsung.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk at kernel.org>
> (backported from commit 9a59b62fd88196844cee5fff851bee2cfd7afb6e upstream)
> Signed-off-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>
> ---
>  fs/f2fs/super.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 97 insertions(+)
> 
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index ec70a2176c57..8c017100b7f7 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -677,6 +677,79 @@ static loff_t max_file_size(unsigned bits)
>  	return result;
>  }
>  
> +static inline bool sanity_check_area_boundary(struct super_block *sb,
> +					struct f2fs_super_block *raw_super)
> +{
> +	u32 segment0_blkaddr = le32_to_cpu(raw_super->segment0_blkaddr);
> +	u32 cp_blkaddr = le32_to_cpu(raw_super->cp_blkaddr);
> +	u32 sit_blkaddr = le32_to_cpu(raw_super->sit_blkaddr);
> +	u32 nat_blkaddr = le32_to_cpu(raw_super->nat_blkaddr);
> +	u32 ssa_blkaddr = le32_to_cpu(raw_super->ssa_blkaddr);
> +	u32 main_blkaddr = le32_to_cpu(raw_super->main_blkaddr);
> +	u32 segment_count_ckpt = le32_to_cpu(raw_super->segment_count_ckpt);
> +	u32 segment_count_sit = le32_to_cpu(raw_super->segment_count_sit);
> +	u32 segment_count_nat = le32_to_cpu(raw_super->segment_count_nat);
> +	u32 segment_count_ssa = le32_to_cpu(raw_super->segment_count_ssa);
> +	u32 segment_count_main = le32_to_cpu(raw_super->segment_count_main);
> +	u32 segment_count = le32_to_cpu(raw_super->segment_count);
> +	u32 log_blocks_per_seg = le32_to_cpu(raw_super->log_blocks_per_seg);
> +
> +	if (segment0_blkaddr != cp_blkaddr) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Mismatch start address, segment0(%u) cp_blkaddr(%u)",
> +			segment0_blkaddr, cp_blkaddr);
> +		return true;
> +	}
> +
> +	if (cp_blkaddr + (segment_count_ckpt << log_blocks_per_seg) !=
> +							sit_blkaddr) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Wrong CP boundary, start(%u) end(%u) blocks(%u)",
> +			cp_blkaddr, sit_blkaddr,
> +			segment_count_ckpt << log_blocks_per_seg);
> +		return true;
> +	}
> +
> +	if (sit_blkaddr + (segment_count_sit << log_blocks_per_seg) !=
> +							nat_blkaddr) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Wrong SIT boundary, start(%u) end(%u) blocks(%u)",
> +			sit_blkaddr, nat_blkaddr,
> +			segment_count_sit << log_blocks_per_seg);
> +		return true;
> +	}
> +
> +	if (nat_blkaddr + (segment_count_nat << log_blocks_per_seg) !=
> +							ssa_blkaddr) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Wrong NAT boundary, start(%u) end(%u) blocks(%u)",
> +			nat_blkaddr, ssa_blkaddr,
> +			segment_count_nat << log_blocks_per_seg);
> +		return true;
> +	}
> +
> +	if (ssa_blkaddr + (segment_count_ssa << log_blocks_per_seg) !=
> +							main_blkaddr) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Wrong SSA boundary, start(%u) end(%u) blocks(%u)",
> +			ssa_blkaddr, main_blkaddr,
> +			segment_count_ssa << log_blocks_per_seg);
> +		return true;
> +	}
> +
> +	if (main_blkaddr + (segment_count_main << log_blocks_per_seg) !=
> +		segment0_blkaddr + (segment_count << log_blocks_per_seg)) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Wrong MAIN_AREA boundary, start(%u) end(%u) blocks(%u)",
> +			main_blkaddr,
> +			segment0_blkaddr + (segment_count << log_blocks_per_seg),
> +			segment_count_main << log_blocks_per_seg);
> +		return true;
> +	}
> +
> +	return false;
> +}
> +
>  static int sanity_check_raw_super(struct super_block *sb,
>  			struct f2fs_super_block *raw_super)
>  {
> @@ -706,6 +779,14 @@ static int sanity_check_raw_super(struct super_block *sb,
>  		return 1;
>  	}
>  
> +	/* check log blocks per segment */
> +	if (le32_to_cpu(raw_super->log_blocks_per_seg) != 9) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Invalid log blocks per segment (%u)\n",
> +			le32_to_cpu(raw_super->log_blocks_per_seg));
> +		return 1;
> +	}
> +
>  	if (le32_to_cpu(raw_super->log_sectorsize) !=
>  					F2FS_LOG_SECTOR_SIZE) {
>  		f2fs_msg(sb, KERN_INFO, "Invalid log sectorsize");
> @@ -724,6 +805,22 @@ static int sanity_check_raw_super(struct super_block *sb,
>  		return 1;
>  	}
>  
> +	/* check reserved ino info */
> +	if (le32_to_cpu(raw_super->node_ino) != 1 ||
> +		le32_to_cpu(raw_super->meta_ino) != 2 ||
> +		le32_to_cpu(raw_super->root_ino) != 3) {
> +		f2fs_msg(sb, KERN_INFO,
> +			"Invalid Fs Meta Ino: node(%u) meta(%u) root(%u)",
> +			le32_to_cpu(raw_super->node_ino),
> +			le32_to_cpu(raw_super->meta_ino),
> +			le32_to_cpu(raw_super->root_ino));
> +		return 1;
> +	}
> +
> +	/* check CP/SIT/NAT/SSA/MAIN_AREA area boundary */
> +	if (sanity_check_area_boundary(sb, raw_super))
> +		return 1;
> +
>  	return 0;
>  }
>  
> 
Looks OK to me.

Acked-by: Colin Ian King <colin.king at canonical.com>