[lxc-devel] [PATCH] Prevent write_config from corrupting container config

[Serge Hallyn]

Quoting Alexander Vladimirov (alexander.idkfa.vladimirov at gmail.com):
> write_config doesn't check the value sig_name function returns,
> this causes write_config to produce corrupted container config when
> using non-predefined signal names.
> 
> Signed-off-by: Alexander Vladimirov <alexander.idkfa.vladimirov at gmail.com>

Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>

> ---
>  src/lxc/confile.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/src/lxc/confile.c b/src/lxc/confile.c
> index 3462e9c..855b816 100644
> --- a/src/lxc/confile.c
> +++ b/src/lxc/confile.c
> @@ -1168,7 +1168,7 @@ static const char *sig_name(int signum) {
>  		if (signum == signames[n].num)
>  			return signames[n].name;
>  	}
> -	return "";
> +	return NULL;
>  }
>  
>  static int sig_parse(const char *signame) {
> @@ -2289,6 +2289,7 @@ void write_config(FILE *fout, struct lxc_conf *c)
>  {
>  	struct lxc_list *it;
>  	int i;
> +	const char *signame;
>  
>  	/* first write any includes */
>  	lxc_list_for_each(it, &c->includes) {
> @@ -2336,10 +2337,22 @@ void write_config(FILE *fout, struct lxc_conf *c)
>  		fprintf(fout, "lxc.pts = %d\n", c->pts);
>  	if (c->ttydir)
>  		fprintf(fout, "lxc.devttydir = %s\n", c->ttydir);
> -	if (c->haltsignal)
> -		fprintf(fout, "lxc.haltsignal = SIG%s\n", sig_name(c->haltsignal));
> -	if (c->stopsignal)
> -		fprintf(fout, "lxc.stopsignal = SIG%s\n", sig_name(c->stopsignal));
> +	if (c->haltsignal) {
> +		signame = sig_name(c->haltsignal);
> +		if (signame == NULL) {
> +			fprintf(fout, "lxc.haltsignal = %d\n", c->haltsignal);
> +		} else {
> +			fprintf(fout, "lxc.haltsignal = SIG%s\n", sig_name(c->haltsignal));
> +		}
> +	}
> +	if (c->stopsignal) {
> +		signame = sig_name(c->stopsignal);
> +		if (signame == NULL) {
> +			fprintf(fout, "lxc.stopsignal = %d\n", c->stopsignal);
> +		} else {
> +			fprintf(fout, "lxc.stopsignal = SIG%s\n", sig_name(c->stopsignal));
> +		}
> +	}
>  	#if HAVE_SYS_PERSONALITY_H
>  	switch(c->personality) {
>  	case PER_LINUX32: fprintf(fout, "lxc.arch = i686\n"); break;
> -- 
> 2.0.0
> 
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