[Crash-utility] [PATCH] fix segfaults in sial during script unload

[Dave Anderson]

Deferring to Luc Chouinard for his ACK.

Thanks,
  Dave


----- Original Message -----
> There are a couple of segfault-causing memory accesses in sial when
> scripts are unloaded.  Also, I noticed a memory leak in the vicinity of
> one of the segfaults.
> 
> The patch below fixes these.
> 
> (1) in reg_callback, while unloading, help_str, an unitialized
>     pointer, is passed to sial_free()
> 
> (2) the help_data pointers are sial_strdup()'d and not freed.  the
>     help_data itself is malloc()'d but not freed
> 
> (3) in sial_deletefile(), the call to sial_freefile() frees the fdata,
>     but it is removed from the list (a process which accesses
>     this fdata) only in sial_findfile(name, 1).
> 
> Rabin
> 
> diff --git a/extensions/libsial/sial_func.c
> b/extensions/libsial/sial_func.c
> index cd4648f..c5373ef 100644
> --- a/extensions/libsial/sial_func.c
> +++ b/extensions/libsial/sial_func.c
> @@ -317,8 +317,8 @@ fdata *fd=sial_findfile(name, 0);
>  
>  	if(fd) {
>  
> -		sial_freefile(fd);
>                  (void)sial_findfile(name, 1);
> +		sial_freefile(fd);
>  		return 1;
>  
>  	}
> diff --git a/extensions/sial.c b/extensions/sial.c
> index 49ae417..3b7df90 100644
> --- a/extensions/sial.c
> +++ b/extensions/sial.c
> @@ -887,6 +887,10 @@ struct command_table_entry *cp, *end;
>      for (cp = command_table; cp->name; cp++) {
>          if (!strcmp(cp->name, name)) {
>              sial_free(cp->name);
> +            sial_free(cp->help_data[0]);
> +            sial_free(cp->help_data[2]);
> +            sial_free(cp->help_data[3]);
> +            free(cp->help_data);
>              memmove(cp, cp+1, sizeof *cp
>              *(NCMDS-(cp-command_table)-1));
>              break;
>          }
> @@ -937,7 +941,6 @@ char **help=malloc(sizeof *help * 5);
>              }
>              else rm_sial_cmd(name);
>          }
> -        sial_free(help_str);
>      }
>      free(help);
>      return;
>