PERFORCE change 32072 for review

[Adam Migus]

Robert,
len can never exceed size which is passed in as the
size of the string.  Therefor the NULL will always
land inside the string.
How exactly does snprintf() fail?

Adam

<quote who="Robert Watson">
> http://perforce.freebsd.org/chv.cgi?CH=32072
>
> Change 32072 by rwatson at rwatson_tislabs on
> 2003/05/29 16:14:02
>
> 	Temporary work-around for overflows in
> externalization of
> 	compartment strings in the Biba and MLS policies.
> Validate
> 	that the nul we slap down in fact lands inside the
> string.
> 	This code generally needs cleaning up, since it
> fails to
> 	handle failures by snprintf().  If the provided
> string is
> 	too short, this result is preferable to kernel
> panics, etc.
>
> Affected files ...
>
> ..
> //depot/projects/trustedbsd/mac/sys/security/mac_biba/mac_biba.c#209
> edit ..
> //depot/projects/trustedbsd/mac/sys/security/mac_mls/mac_mls.c#167
> edit
>
> Differences ...
>
> ====
> //depot/projects/trustedbsd/mac/sys/security/mac_biba/mac_biba.c#209
> (text+ko) ====
>
> @@ -583,7 +583,11 @@
>  		} while(bit <= MAC_BIBA_MAX_COMPARTMENTS);
>
>  		len = size - left - 1;
> -		string[len] = '\0';
> +		if (len > 0 && len < size)
> +			string[len] = '\0';
> +		else
> +			string[0] = '\0';
> +
>  		return (len);
>
>  	default:
>
> ====
> //depot/projects/trustedbsd/mac/sys/security/mac_mls/mac_mls.c#167
> (text+ko) ====
>
> @@ -547,7 +547,10 @@
>  		} while(bit <= MAC_MLS_MAX_COMPARTMENTS);
>
>  		len = size - left - 1;
> -		string[len] = '\0';
> +		if (len > 0 && len < size)
> +			string[len] = '\0';
> +		else
> +			string[0] = '\0';
>  		return (len);
>
>  	default:


-- 
Adam Migus - Research Scientist
Network Associates Laboratories (http://www.nailabs.com)
FreeBSD (http://www.freebsd.org)
God may be subtle, but He isn't plain mean.  -- Albert
Einstein



To Unsubscribe: send mail to majordomo at trustedbsd.org
with "unsubscribe trustedbsd-cvs" in the body of the message