Re: [PATCH] IpAdress truncates printed port that exceeds 9999

On 05/01/2010 07:49 PM, Amos Jeffries wrote:
> Alex Rousskov wrote:
>> Fixed IpAddress port printing for ports higher than 9999:
>> snprintf includes zero-terminator in its size limit, so 7
>> rather than 6 bytes are needed to snprintf a colon followed
>> by 5 port digits.
>>
>> Whether the bug has any runtime effects in the current code,
>> I do not know, but I did waste a few hours following
>> misleading debugging output.

> +1. Please commit with tweak:

Committed (r10494). Please port to v3.1 (the original patch may work).

> MAX_IPSTRLEN definition needs +1 as well to prevent this introducing a
> buffer overflow.

ToURL() operates on a buffer of blen length (not necessarily
MAX_IPSTRLEN) and already checks for overflows. I do not see how it can
cause a buffer overflow even if MAX_IPSTRLEN is 0.

If you are not worried about overflows in ToURL() but about MAX_IPSTRLEN
being too small, current MAX_IPSTRLEN=75 is probably already more than
any IP address can consume:

  IPv4: 22 (xxx.xxx.xxx.xxx:ppppp)
  IPv6: 1+45+1+7=54?
(http://stackoverflow.com/questions/166132/maximum-length-of-the-textual-representation-of-an-ipv6-address)

Did I miss something?

Thank you,

Alex.
Received on Sun May 23 2010 - 22:56:42 MDT