[libvirt] [PATCH 5/5] leasehelper: Refactor copying of old entries to avoid double free

[Pavel Hrdina]

On 16.6.2014 17:21, Peter Krempa wrote:

s/leasehelper/leaseshelper/ in subject

> When copying entries from the old lease file into the new array the old
> code would copy the pointer of the json object into the second array
> without removing it from the first. Afterwards when both arrays were
> freed this might lead to a crash due to access of already freed memory.
> 
> Refactor the code to use the new array item stealing helper added to the
> json code so that the entry resides just in one array.
> ---
>  src/network/leaseshelper.c | 79 +++++++++++++++++++++++++---------------------
>  1 file changed, 43 insertions(+), 36 deletions(-)
> 

[..]

> -        /* Check whether lease has to be included or not */
> -        if (delete && STREQ(ip_tmp, ip))
> -            continue;
> +                /* Move old lease to new array */
> +                lease_tmp = virJSONValueArraySteal(leases_array, i);

There is a possible memory leak if the append fails. Probably move this
function after the successful append and ignore the return value.

> 
> -        /* Add old lease to new array */
> -        if (virJSONValueArrayAppend(leases_array_new, lease_tmp) < 0) {
> -            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> -                           _("failed to create json"));
> -            goto cleanup;
> +                if (virJSONValueArrayAppend(leases_array_new, lease_tmp) < 0) {
> +                    virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                                   _("failed to create json"));
> +                    goto cleanup;
> +                }
> +            }
>          }
>      }
> 

ACK with changes

Pavel