[libvirt] [PATCHv2 1/6] maint: don't leave garbage on early API exit

[Ján Tomko]

On 01/14/2014 10:43 PM, Eric Blake wrote:
> Several APIs clear out a user input buffer before attempting to
> populate it; but in a few cases we missed this memset if we
> detect a reason for an early exit.  Note that these APIs
> check for non-NULL arguments, and exit early with an error
> message when NULL is passed in; which means that we must be
> careful to avoid a NULL deref in order to get to that error
> message.  Also, we were inconsistent on the use of
> sizeof(virType) vs. sizeof(expression); the latter is more
> robust if we ever change the type of the expression (although
> such action is unlikely since these types are part of our
> public API).
> 
> * src/libvirt.c (virDomainGetInfo, virDomainGetBlockInfo)
> (virStoragePoolGetInfo, virStorageVolGetInfo)
> (virDomainGetJobInfo, virDomainGetBlockJobInfo): Move memset
> before any returns.
> 
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
> 
> v2 avoid null deref, prefer sizeof(expr)
> 
>  src/libvirt.c | 29 +++++++++++++++++------------
>  1 file changed, 17 insertions(+), 12 deletions(-)
> 

> @@ -8449,12 +8450,12 @@ virDomainGetBlockInfo(virDomainPtr domain, const char *disk,
> 
>      virResetLastError();
> 

if (info)
> +    memset(info, 0, sizeof(*info));
> +


>      virCheckDomainReturn(domain, -1);
>      virCheckNonNullArgGoto(disk, error);
>      virCheckNonNullArgGoto(info, error);
> 
> -    memset(info, 0, sizeof(virDomainBlockInfo));
> -
>      conn = domain->conn;
> 
>      if (conn->driver->domainGetBlockInfo) {

Jan

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