linux-ext4 - Re: [PATCH 1/3] ext4: do not allow external inodes for inline data

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Message-Id: <46535DCA-9911-4BED-9FFD-F822698F9928@dilger.ca>
Date:   Thu, 24 May 2018 10:45:20 -0600
From:   Andreas Dilger <adilger@...ger.ca>
To:     Theodore Ts'o <tytso@....edu>
Cc:     Ext4 Developers List <linux-ext4@...r.kernel.org>,
        wen.xu@...ech.edu, jannh@...gle.com
Subject: Re: [PATCH 1/3] ext4: do not allow external inodes for inline data

On May 23, 2018, at 9:37 AM, Theodore Ts'o <tytso@....edu> wrote:
> 
> The inline data feature was implemented before we added support for
> external inodes for xattrs.  It makes no sense to support that
> combination, but the problem is that there are a number of extended
> attribute checks that are skipped if e_value_inum is non-zero.
> 
> Unfortunately, the inline data code is completely e_value_inum
> unaware, and attempts to interpret the xattr fields as if it were an
> inline xattr --- at which point, Hilarty Ensues.
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=199803
> 
> Reported-by: Jann Horn <jannh@...gle.com>
> Signed-off-by: Theodore Ts'o <tytso@....edu>

Reviewed-by: Andreas Dilger <adilger@...ger.ca>

> Fixes: e50e5129f384 ("ext4: xattr-in-inode support")
> Cc: stable@...nel.org
> ---
> fs/ext4/inline.c | 6 ++++++
> 1 file changed, 6 insertions(+)
> 
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index 70cf4c7b268a..44b4fcdc3755 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -144,6 +144,12 @@ int ext4_find_inline_data_nolock(struct inode *inode)
> 		goto out;
> 
> 	if (!is.s.not_found) {
> +		if (is.s.here->e_value_inum) {
> +			EXT4_ERROR_INODE(inode, "inline data xattr refers "
> +					 "to an external xattr inode");
> +			error = -EFSCORRUPTED;
> +			goto out;
> +		}
> 		EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
> 					(void *)ext4_raw_inode(&is.iloc));
> 		EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
> --
> 2.16.1.72.g5be1f00a9a
> 


Cheers, Andreas






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