svn commit: r324971 - head/sys/netinet

[Michael Tuexen]

> On 25. Oct 2017, at 16:57, Rodney W. Grimes <freebsd at pdx.rh.CN85.dnsmgr.net> wrote:
> 
> [ Charset UTF-8 unsupported, converting... ]
>> Author: tuexen
>> Date: Wed Oct 25 09:12:22 2017
>> New Revision: 324971
>> URL: https://svnweb.freebsd.org/changeset/base/324971
>> 
>> Log:
>>  Fix a bug reported by Felix Weinrank using the libfuzzer on the
>>  userland stack.
> 
> Please try to say what the bug was, why it was a bug, and
> how it was fixed in any bug commit message.
Yepp, you are right. The bug was that when taking the length
of what is used in a buffer, the offset was not taken into account.
The fix is to do that...

Best regards
Michael
> 
> External vague references are of little value when reading
> through a files svn history.
> 
> Thanks,
>> 
>>  MFC after:	3 days
>> 
>> Modified:
>>  head/sys/netinet/sctp_auth.c
>> 
>> Modified: head/sys/netinet/sctp_auth.c
>> ==============================================================================
>> --- head/sys/netinet/sctp_auth.c	Wed Oct 25 05:55:13 2017	(r324970)
>> +++ head/sys/netinet/sctp_auth.c	Wed Oct 25 09:12:22 2017	(r324971)
>> @@ -1606,9 +1606,9 @@ sctp_zero_m(struct mbuf *m, uint32_t m_offset, uint32_
>> 	/* now use the rest of the mbuf chain */
>> 	while ((m_tmp != NULL) && (size > 0)) {
>> 		data = mtod(m_tmp, uint8_t *)+m_offset;
>> -		if (size > (uint32_t)SCTP_BUF_LEN(m_tmp)) {
>> -			memset(data, 0, SCTP_BUF_LEN(m_tmp));
>> -			size -= SCTP_BUF_LEN(m_tmp);
>> +		if (size > (uint32_t)(SCTP_BUF_LEN(m_tmp) - m_offset)) {
>> +			memset(data, 0, SCTP_BUF_LEN(m_tmp) - m_offset);
>> +			size -= SCTP_BUF_LEN(m_tmp) - m_offset;
>> 		} else {
>> 			memset(data, 0, size);
>> 			size = 0;
>> 
>> 
> 
> -- 
> Rod Grimes                                                 rgrimes at freebsd.org
>