Re: [PATCH] ecryptfs: validate auth tok payload and sKEK size

[syzbot <syzbot+03c68e42ce4b33f7ce9b@syzkaller.appspotmail.com>]

> #syz test

"" does not look like a valid git branch or commit.

>  fs/ecryptfs/ecryptfs_kernel.h | 6 ++++++
>  fs/ecryptfs/keystore.c        | 7 +++++++
>  2 files changed, 13 insertions(+)
>
> diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
> index 58165928ed1e..4315c18ba1cd 100644
> --- a/fs/ecryptfs/ecryptfs_kernel.h
> +++ b/fs/ecryptfs/ecryptfs_kernel.h
> @@ -88,6 +88,9 @@ ecryptfs_get_encrypted_key_payload_data(struct key *key)
>  	if (!payload)
>  		return ERR_PTR(-EKEYREVOKED);
>  
> +	if (payload->payload_datalen < sizeof(struct ecryptfs_auth_tok))
> +		return ERR_PTR(-EINVAL);
> +
>  	return (struct ecryptfs_auth_tok *)payload->payload_data;
>  }
>  
> @@ -124,6 +127,9 @@ ecryptfs_get_key_payload_data(struct key *key)
>  	if (!ukp)
>  		return ERR_PTR(-EKEYREVOKED);
>  
> +	if (ukp->datalen < sizeof(struct ecryptfs_auth_tok))
> +		return ERR_PTR(-EINVAL);
> +
>  	return (struct ecryptfs_auth_tok *)ukp->data;
>  }
>  
> diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
> index 51651314b7a6..7f2dbc81fcbc 100644
> --- a/fs/ecryptfs/keystore.c
> +++ b/fs/ecryptfs/keystore.c
> @@ -477,6 +477,13 @@ ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
>  		rc = -EINVAL;
>  		goto out;
>  	}
> +	if ((*auth_tok)->token_type == ECRYPTFS_PASSWORD
> +	    && (*auth_tok)->token.password.session_key_encryption_key_bytes
> +	       > ECRYPTFS_MAX_KEY_BYTES) {
> +		printk(KERN_ERR "Invalid password auth_tok sKEK size\n");
> +		rc = -EINVAL;
> +		goto out;
> +	}
>  out:
>  	return rc;
>  }
> -- 
> 2.51.0
>