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Re: [libvirt] [PATCH] esx: Avoid Coverity warning about resource leak in esxOpen



This issue (and the same for hyperv) was tracked down to a Coverity
problem. For context see:

https://www.redhat.com/archives/libvir-list/2013-January/msg01504.html

Essentially the esxFreePrivate(&priv); and subsequent VIR_FREE(*priv)
caused the issue.

Also see: https://communities.coverity.com/thread/2655

John

On 01/10/2013 04:47 PM, Matthias Bolte wrote:
> Commit 4445e16bfa8056980ac643fabf17186f9e685925 changed the signature
> of esxConnectToHost and esxConnectToVCenter by replacing the esxPrivate
> pointer with virConnectPtr. The esxPrivate pointer was then retrieved
> again from virConnectPtr's privateData. This resulted in a NULL pointer
> dereference, because the privateData pointer was not yet initialized at
> the point where esxConnectToHost and esxConnectToVCenter are called.
> 
> This was fixed in commit b126715a48cd0cbe32ec6468c267cd8cf2961c55 that
> moved the initialization of privateData before the problematic calls.
> 
> Coverity tagged the esxPrivate pointer a potentially leaked because of
> the conditional free call. But this is a false positive, there is not
> actual leak.
> 
> Avoid this warning from Coverity by making the call to esxFreePrivate
> unconditional and changing esxConnectToHost and esxConnectToVCenter back
> to take a esxPrivate pointer directly. This allows to assign esxPrivate
> to the virConnectPtr's privateData pointer as one of the last steps in
> esxOpen making it more obvious that it is not initialized during the
> earlier steps of esxOpen.
> ---
> 
> This patch is meant as a replacement this patch:
> 
> https://www.redhat.com/archives/libvir-list/2013-January/msg00530.html
> 
>  src/esx/esx_driver.c |   23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/src/esx/esx_driver.c b/src/esx/esx_driver.c
> index 1366c81..dad10a1 100644
> --- a/src/esx/esx_driver.c
> +++ b/src/esx/esx_driver.c
> @@ -650,7 +650,8 @@ esxCapsInit(esxPrivate *priv)
>  
>  
>  static int
> -esxConnectToHost(virConnectPtr conn,
> +esxConnectToHost(esxPrivate *priv,
> +                 virConnectPtr conn,
>                   virConnectAuthPtr auth,
>                   char **vCenterIpAddress)
>  {
> @@ -663,7 +664,6 @@ esxConnectToHost(virConnectPtr conn,
>      esxVI_String *propertyNameList = NULL;
>      esxVI_ObjectContent *hostSystem = NULL;
>      esxVI_Boolean inMaintenanceMode = esxVI_Boolean_Undefined;
> -    esxPrivate *priv = conn->privateData;
>      esxVI_ProductVersion expectedProductVersion = STRCASEEQ(conn->uri->scheme, "esx")
>          ? esxVI_ProductVersion_ESX
>          : esxVI_ProductVersion_GSX;
> @@ -785,7 +785,8 @@ esxConnectToHost(virConnectPtr conn,
>  
>  
>  static int
> -esxConnectToVCenter(virConnectPtr conn,
> +esxConnectToVCenter(esxPrivate *priv,
> +                    virConnectPtr conn,
>                      virConnectAuthPtr auth,
>                      const char *hostname,
>                      const char *hostSystemIpAddress)
> @@ -796,7 +797,6 @@ esxConnectToVCenter(virConnectPtr conn,
>      char *unescapedPassword = NULL;
>      char *password = NULL;
>      char *url = NULL;
> -    esxPrivate *priv = conn->privateData;
>  
>      if (hostSystemIpAddress == NULL &&
>          (priv->parsedUri->path == NULL || STREQ(priv->parsedUri->path, "/"))) {
> @@ -1008,8 +1008,6 @@ esxOpen(virConnectPtr conn, virConnectAuthPtr auth,
>      priv->supportsLongMode = esxVI_Boolean_Undefined;
>      priv->usedCpuTimeCounterId = -1;
>  
> -    conn->privateData = priv;
> -
>      /*
>       * Set the port dependent on the transport protocol if no port is
>       * specified. This allows us to rely on the port parameter being
> @@ -1036,7 +1034,7 @@ esxOpen(virConnectPtr conn, virConnectAuthPtr auth,
>      if (STRCASEEQ(conn->uri->scheme, "esx") ||
>          STRCASEEQ(conn->uri->scheme, "gsx")) {
>          /* Connect to host */
> -        if (esxConnectToHost(conn, auth,
> +        if (esxConnectToHost(priv, conn, auth,
>                               &potentialVCenterIpAddress) < 0) {
>              goto cleanup;
>          }
> @@ -1075,7 +1073,7 @@ esxOpen(virConnectPtr conn, virConnectAuthPtr auth,
>                  }
>              }
>  
> -            if (esxConnectToVCenter(conn, auth,
> +            if (esxConnectToVCenter(priv, conn, auth,
>                                      vCenterIpAddress,
>                                      priv->host->ipAddress) < 0) {
>                  goto cleanup;
> @@ -1085,7 +1083,7 @@ esxOpen(virConnectPtr conn, virConnectAuthPtr auth,
>          priv->primary = priv->host;
>      } else { /* VPX */
>          /* Connect to vCenter */
> -        if (esxConnectToVCenter(conn, auth,
> +        if (esxConnectToVCenter(priv, conn, auth,
>                                  conn->uri->server,
>                                  NULL) < 0) {
>              goto cleanup;
> @@ -1101,13 +1099,12 @@ esxOpen(virConnectPtr conn, virConnectAuthPtr auth,
>          goto cleanup;
>      }
>  
> +    conn->privateData = priv;
> +    priv = NULL;
>      result = VIR_DRV_OPEN_SUCCESS;
>  
>    cleanup:
> -    if (result == VIR_DRV_OPEN_ERROR) {
> -        esxFreePrivate(&priv);
> -    }
> -
> +    esxFreePrivate(&priv);
>      VIR_FREE(potentialVCenterIpAddress);
>  
>      return result;
> 


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