Function parse_content_length

parser/parse_content.c:227–273

char* parse_content_length( char* buffer, char* end, int* length)
{
	int number;
	char *p, *numstart;

	p = buffer;
	/* search the beginning of the number */
	while ( p<end && (*p==' ' || *p=='\t'
	              || (*p=='\r' && p+1<end && *(p+1)=='\n')
	              || (*p=='\n' && p+1<end && (*(p+1)==' '||*(p+1)=='\t')) ))
		p++;
	if (p==end)
		goto error;
	/* parse the number */
	numstart = p;
	number = 0;
	while (p<end && *p>='0' && *p<='9') {
		/* do not actually cause an integer overflow, as it is UB! --liviu */
		if (number >= INT_MAX/10) {
			LM_ERR("integer overflow risk at pos %d in length value [%.*s]\n",
				(int)(p-buffer),(int)(end-buffer), buffer);
			return NULL;
		}

		number = number*10 + ((*p)-'0');
		p++;
	}
	if (p==end || p==numstart)
		goto error;

	/* now we should have only spaces at the end */
	while ( p<end && (*p==' ' || *p=='\t'
	              || (*p=='\n' && p+1<end && (*(p+1)==' '||*(p+1)=='\t')) ))
		p++;
	if (p==end)
		goto error;
	/* the header ends proper? */
	if ( (*(p++)!='\n') && (*(p-1)!='\r' || p==end || *(p++)!='\n' ) )
		goto error;

	*length = number;
	return p;
error:
	LM_ERR("parse error at pos %ld, dec-char: %d, start/p/end: %p/%p/%p\n",
	       (long)(p - buffer), p < end && (end-buffer) ? *p:-1, buffer, p, end);
	return NULL;
}