[apparmor] [PATCH 3/5] Library interface for tasks introspectingconfinement.

[Kees Cook]

On Thu, Jul 21, 2011 at 01:40:58PM -0700, John Johansen wrote:
> +int aa_getpeercon_raw(int fd, char *buffer, int *size)
> +{
> +	socklen_t optlen = *size;
> +	int rc = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, buffer, &optlen);
> +	if (rc == -1)
> +		goto out;

This should check size and *size>0 before assigning optlen, otherwise we
run a risk of blowing up on the buffer[optlen-1] check. Should check
for buffer!=NULL too.

> +	/* check for null termination */
> +	if (buffer[optlen - 1] != 0) {
> +		if (optlen < *size) {
> +			buffer[optlen] = 0;
> +			optlen++;
> +		} else {
> +			/* buffer needs to be bigger by 1 */
> +			rc = -1;
> +			errno = ERANGE;
> +			optlen++;
> +		}
> +	}
> +out:
> +	*size = optlen;
> +	return rc;
> +}

> +int aa_getpeercon(int fd, char **con)
> +{
> +	int rc, size = INITIAL_GUESS_SIZE;

Check for con != NULL here?

> +	char *buffer = NULL;
> +
> +	do {
> +		buffer = realloc(buffer, size);
> +		if (!buffer)
> +			return -1;
> +		memset(buffer, 0, size);
> +
> +		rc = aa_getpeercon_raw(fd, buffer, &size);
> +	} while (rc == -1 && errno == ERANGE);
> +
> +	if (rc == -1) {
> +		free(buffer);
> +		size = -1;
> +	} else
> +		*con = buffer;
> +
> +	return size;
> +}

> +        aa_getpeercon_raw;
> +        aa_getpeercon;
>          parse_record;
>          free_record;
>          aa_getprocattr_raw;

Does it make sense to export the _raw functions? I'm sort of mentally on
the fence about that.

Looks excellent overall :)

-Kees

-- 
Kees Cook
Ubuntu Security Team