[Libguestfs] [PATCH] drives: fix deletion of servers on error

[Richard W.M. Jones]

On Mon, Aug 18, 2014 at 02:56:08PM +0200, Pino Toscano wrote:
> Make sure to not skip any of the created server, and to always free
> the "server" array.
> diff --git a/src/drives.c b/src/drives.c
> index 4bd8328..85c1495 100644
> --- a/src/drives.c
> +++ b/src/drives.c
> @@ -743,8 +743,7 @@ parse_servers (guestfs_h *g, char *const *strs,
> 
>    for (i = 0; i < n; ++i) {
>      if (parse_one_server (g, strs[i], &servers[i]) == -1) {
> -      if (i > 0)
> -        free_drive_servers (servers, i-1);
> +      free_drive_servers (servers, i);
>        return -1;
>      }
>    }
> ---
>  src/drives.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/src/drives.c b/src/drives.c
> index 4bd8328..85c1495 100644
> --- a/src/drives.c
> +++ b/src/drives.c
> @@ -743,8 +743,7 @@ parse_servers (guestfs_h *g, char *const *strs,
>  
>    for (i = 0; i < n; ++i) {
>      if (parse_one_server (g, strs[i], &servers[i]) == -1) {
> -      if (i > 0)
> -        free_drive_servers (servers, i-1);
> +      free_drive_servers (servers, i);
>        return -1;
>      }
>    }
> -- 
> 1.9.3

The original code is attempting to avoid a double-free of
servers[i].u.hostname.  I think this change would mean the double-free
would happen again.

Rich.

-- 
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