[PATCH 04/11] Add backend support for suboridnate uids and gids

Serge E. Hallyn serge at hallyn.com
Wed Jan 23 18:22:06 UTC 2013


Quoting Eric W. Biederman (ebiederm at xmission.com):
> +static void *subordinate_parse (const char *line)
> +{
> +	static struct subordinate_range range;
> +	char rangebuf[1024];
> +	int i;
> +	char *cp;
> +	char *fields[NFIELDS];
> +
> +	/*
> +	 * Copy the string to a temporary buffer so the substrings can
> +	 * be modified to be NULL terminated.
> +	 */
> +	if (strlen (line) >= sizeof rangebuf)
> +		return NULL;	/* fail if too long */
> +	strcpy (rangebuf, line);
> +
> +	/*
> +	 * Save a pointer to the start of each colon separated
> +	 * field.  The fields are converted into NUL terminated strings.
> +	 */
> +
> +	for (cp = rangebuf, i = 0; (i < NFIELDS) && (NULL != cp); i++) {
> +		fields[i] = cp;
> +		while (('\0' != *cp) && (':' != *cp)) {
> +			cp++;
> +		}
> +
> +		if ('\0' != *cp) {
> +			*cp = '\0';
> +			cp++;
> +		} else {
> +			cp = NULL;
> +		}
> +	}
> +
> +	/*
> +	 * There must be exactly NFIELDS colon separated fields or
> +	 * the entry is invalid.  Also, fields must be non-blank.
> +	 */
> +	if (i != NFIELDS || *fields[0] == '\0' || *fields[1] == '\0' || *fields[2] == '\0')
> +		return NULL;
> +	range.owner = fields[0];
> +	if (getulong (fields[1], &range.start) == 0)
> +		return NULL;
> +	if (getulong (fields[2], &range.count) == 0)
> +		return NULL;
> +
> +	return &range;

This function worries me, because you're returning local contents (both range
itself, and range.owner).

-serge


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