cvs commit: src Makefile.inc1 src/lib/libc/gen __xuname.c getosreldate.c

[Garance A Drosehn]

At 6:57 AM -0800 12/2/05, Doug Ambrisko wrote:
>Pawel Jakub Dawidek writes:
>| [...]
>| +> 	name->sysname[sizeof(name->sysname) - 1] = '\0';
>| +> +	if ((p = getenv("UNAME_s")))
>| +> +		strncpy(name->sysname, p, sizeof(name->sysname));
>| [...]
>| +> 	name->release[sizeof(name->release) - 1] = '\0';
>| +> +	if ((p = getenv("UNAME_r")))
>| +> +		strncpy(name->release, p, sizeof(name->release));
>| [...]
>| +> +	if ((p = getenv("UNAME_v")))
>| +> +		strncpy(name->version, p, sizeof(name->version));
>| [...]
>| +> 	name->machine[sizeof(name->machine) - 1] = '\0';
>| +> +	if ((p = getenv("UNAME_m")))
>| +> +		strncpy(name->machine, p, sizeof(name->machine));
>|
>| As you can see, previous code tried to NULL-terminate buffer
>| copied using strncpy(3) properly and you inserted your changes
>| after these terminations. Please, NULL-terminate the buffers
>| after using strncpy(3).
>
>The prior code had to NULL-terminate by hand since the data could
>come from the sysctl not NULL-terminate.  I thought the strncpy
>would NULL-terminate but you are correct.

strncpy is meant for strings where you don't want null-termination
(such as fixed-length fields in structs).  It was not meant for
situations like this.  Code like this should use strlcpy() instead.

-- 
Garance Alistair Drosehn     =      gad at gilead.netel.rpi.edu
Senior Systems Programmer               or   gad at FreeBSD.org
Rensselaer Polytechnic Institute;             Troy, NY;  USA