[libvirt] [PATCH] Use virGetHostname instead of gethostname.

[Daniel P. Berrange]

On Fri, Jul 31, 2009 at 03:19:53PM +0200, Chris Lalancette wrote:
> Fix up qemudDomainMigratePrepare2 to use virGetHostname instead of
> gethostname.  Besides the fact that virGetHostname is far more clever,
> there was a latent bug in the handling that could cause a buffer overflow
> on a very long hostname.
> 
> Signed-off-by: Chris Lalancette <clalance at redhat.com>
> ---
>  src/qemu_driver.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/src/qemu_driver.c b/src/qemu_driver.c
> index cee2164..83cbcf3 100644
> --- a/src/qemu_driver.c
> +++ b/src/qemu_driver.c
> @@ -6270,11 +6270,12 @@ qemudDomainMigratePrepare2 (virConnectPtr dconn,
>      virDomainDefPtr def = NULL;
>      virDomainObjPtr vm = NULL;
>      int this_port;
> -    char hostname [HOST_NAME_MAX+1];
> +    char *hostname;
>      char migrateFrom [64];
>      const char *p;
>      virDomainEventPtr event = NULL;
>      int ret = -1;;
> +    int internalret;
>  
>      *uri_out = NULL;
>  
> @@ -6300,14 +6301,16 @@ qemudDomainMigratePrepare2 (virConnectPtr dconn,
>          if (port == QEMUD_MIGRATION_NUM_PORTS) port = 0;
>  
>          /* Get hostname */
> -        if (gethostname (hostname, HOST_NAME_MAX+1) == -1) {
> +        if ((hostname = virGetHostname()) == NULL) {
>              virReportSystemError (dconn, errno,
>                                    "%s", _("failed to determine host name"));
>              goto cleanup;
>          }
>  
>          /* Caller frees */
> -        if (virAsprintf(uri_out, "tcp:%s:%d", hostname, this_port) < 0) {
> +        internalret = virAsprintf(uri_out, "tcp:%s:%d", hostname, this_port);
> +        VIR_FREE(hostname);
> +        if (internalret < 0) {
>              virReportOOMError (dconn);
>              goto cleanup;
>          }

ACK

Daniel
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