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Date: Fri, 21 Jun 2002 03:56:18 -0700 (PDT)
From: Peter N Lewis <peter@stairways.com.au>
To: freebsd-gnats-submit@FreeBSD.org
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Subject: bin/39617: traceroute fd_set allocation bug
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>Number:         39617
>Category:       bin
>Synopsis:       traceroute fd_set allocation bug
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Jun 21 04:00:09 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Peter N Lewis
>Release:        N/A
>Organization:
Stairways Software
>Environment:
N/A
>Description:
traceroute.c does this:
	nfds = howmany(sock + 1, NFDBITS);
	if ((fdsp = malloc(nfds)) == NULL)
		err(1, "malloc");
	memset(fdsp, 0, nfds);

this is not valid since the fd_set is made up of fd_mask.  nfds should be:

	nfds = howmany(sock + 1, NFDBITS) * sizeof(fd_mask);

>How-To-Repeat:
Run traceroute with pre-opened files such that sock (global variable s, the receiving socket) is greater than 7.  In normal operation, it is usally 3 or 4 which is why this bug remains undetected.
>Fix:
	nfds = howmany(sock + 1, NFDBITS) * sizeof(fd_mask);

>Release-Note:
>Audit-Trail:
>Unformatted:

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