Missing OOM checks in libpq (was Re: Replication connection URI?)

On 11/24/2014 06:05 PM, Alex Shulgin wrote:
> The first patch is not on topic, I just spotted this missing check.

> *** a/src/interfaces/libpq/fe-connect.c
> --- b/src/interfaces/libpq/fe-connect.c
> *************** conninfo_array_parse(const char *const *
> *** 4402,4407 ****
> --- 4402,4415 ----
>                                   if (options[k].val)
>                                       free(options[k].val);
>                                   options[k].val = strdup(str_option->val);
> +                                 if (!options[k].val)
> +                                 {
> +                                     printfPQExpBuffer(errorMessage,
> +                                                       libpq_gettext("out of memory\n"));
> +                                     PQconninfoFree(options);
> +                                     PQconninfoFree(dbname_options);
> +                                     return NULL;
> +                                 }
>                                   break;
>                               }
>                           }

Oh. There are actually many more places in connection option parsing
that don't check the return value of strdup(). The one in fillPGConn
even has an XXX comment saying it probably should check it. You can get
quite strange behavior if one of them fails. If for example the strdup()
on dbname fails, you might end up connecting to different database than
intended. And if the "conn->sslmode = strdup(DefaultSSLMode);" call in
connectOptions2 fails, you'll get a segfault later because at least
connectDBstart assumes that sslmode is not NULL.

I think we need to fix all of those, and backpatch. Per attached.

- Heikki