[PATCH] Fix pb-discover segfaults caused by list corruption.

[Samuel Mendoza-Jonas]

On Sun, 2018-06-10 at 13:21 -0500, Brandon Bergren wrote:
> I was seeing list corruption and segfaults in pb-discover on my Talos
> II when using both yaboot and kboot config files on the same device.
> 
> My assumption is that discover_context_add_boot_option() was being
> called on the same pointer more than once.
> 
> So, null the pointer right after the call. The ownership was transferred
> anyway so the parsers should not keep it around.
> 
> Signed-off-by: Brandon Bergren <git at bdragon.rtk0.net>

Ouch! Merged as 3295293.

Thanks,
Sam

> ---
>  discover/pxe-parser.c      | 1 +
>  discover/syslinux-parser.c | 1 +
>  discover/yaboot-parser.c   | 1 +
>  3 files changed, 3 insertions(+)
> 
> diff --git a/discover/pxe-parser.c b/discover/pxe-parser.c
> index fd8b8e8..470dd83 100644
> --- a/discover/pxe-parser.c
> +++ b/discover/pxe-parser.c
> @@ -41,6 +41,7 @@ static void pxe_finish(struct conf_context *conf)
>  		if (info->proxy)
>  			info->opt->proxy = talloc_strdup(info->opt, info->proxy);
>  		discover_context_add_boot_option(conf->dc, info->opt);
> +		info->opt = NULL;
>  	}
>  }
>  
> diff --git a/discover/syslinux-parser.c b/discover/syslinux-parser.c
> index be7b94a..c611ac9 100644
> --- a/discover/syslinux-parser.c
> +++ b/discover/syslinux-parser.c
> @@ -408,6 +408,7 @@ static void syslinux_finalize(struct conf_context *conf)
>  		conf_strip_str(opt->description);
>  
>  		discover_context_add_boot_option(dc, d_opt);
> +		d_opt = NULL;
>  		continue;
>  
>  fail:
> diff --git a/discover/yaboot-parser.c b/discover/yaboot-parser.c
> index 42db95b..b06248f 100644
> --- a/discover/yaboot-parser.c
> +++ b/discover/yaboot-parser.c
> @@ -172,6 +172,7 @@ static void yaboot_finish(struct conf_context *conf)
>  		state->opt->option->is_default = true;
>  
>  	discover_context_add_boot_option(conf->dc, state->opt);
> +	state->opt = NULL;
>  }
>  
>  static void yaboot_process_pair(struct conf_context *conf, const char *name,