linux-kernel - Re: [PATCH][next] EVM: fix memory leak of temporary buffer 'temp'

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Message-Id: <1527778822.3427.13.camel@linux.vnet.ibm.com>
Date:   Thu, 31 May 2018 11:00:22 -0400
From:   Mimi Zohar <zohar@...ux.vnet.ibm.com>
To:     Colin King <colin.king@...onical.com>,
        Matthew Garrett <mjg59@...gle.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E . Hallyn" <serge@...lyn.com>,
        linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] EVM: fix memory leak of temporary buffer 'temp'

On Sun, 2018-05-27 at 23:15 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The allocation of 'temp' is not kfree'd and hence there is a memory
> leak on each call of evm_read_xattrs.  Fix this by kfree'ing it
> after copying data from it back to the user space buffer 'buf'.
> 
> Detected by CoverityScan, CID#1469386 ("Resource Leak")
> 
> Fixes: fa516b66a1bf ("EVM: Allow runtime modification of the set of verified xattrs")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

Thanks, this patch and "EVM: Fix null dereference on xattr when xattr
fails to allocate" are queued in the next-integrity branch.

Mimi

> ---
>  security/integrity/evm/evm_secfs.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
> index a7a0a1acae99..fb8bc950aceb 100644
> --- a/security/integrity/evm/evm_secfs.c
> +++ b/security/integrity/evm/evm_secfs.c
> @@ -158,6 +158,8 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
>  	mutex_unlock(&xattr_list_mutex);
>  	rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
> 
> +	kfree(temp);
> +
>  	return rc;
>  }
>