Date: Thu, 21 Nov 2013 17:38:14 GMT From: Shawn Webb <lattera@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/184149: [vimage] IPv6 link-local collisions on epair[n]b devices Message-ID: <201311211738.rALHcE7P095510@oldred.freebsd.org> Resent-Message-ID: <201311211740.rALHe1G6027702@freefall.freebsd.org>
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>Number: 184149 >Category: kern >Synopsis: [vimage] IPv6 link-local collisions on epair[n]b devices >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: Thu Nov 21 17:40:01 UTC 2013 >Closed-Date: >Last-Modified: >Originator: Shawn Webb >Release: FreeBSD 11-RELEASE >Organization: >Environment: FreeBSD shawn-vm-host 11.0-CURRENT FreeBSD 11.0-CURRENT #56 e78422d(soldierx/lattera/aslr)-dirty: Thu Nov 21 01:18:36 EST 2013 shawn@shawn-vm-host:/usr/obj/usr/src/sys/SEC amd64 >Description: Certain epair[n]b devices can get collisions with other epair[n]b devices due to the MAC address not being random enough. I have a box with a number of vnet jails. Devices epair9b and epair13b shared the same IPv6 link-local address due to how the link-local address was automatically generated from the MAC address. Patch for review included. >How-To-Repeat: ifconfig bridge0 create ifconfig epair9a create ifconfig bridge0 addm epair9a ifconfig epair13a create ifconfig bridge0 addm epair13a ifconfg epair9a up ifconfig epair13a up ifconfig epair9b up ifconfig epair13b up >Fix: diff --git a/sys/net/if_epair.c b/sys/net/if_epair.c index 03e379b..d64940f 100644 --- a/sys/net/if_epair.c +++ b/sys/net/if_epair.c @@ -722,6 +722,8 @@ epair_clone_create(struct if_clone *ifc, char *name, size_t len, caddr_t params) ifp = scb->ifp; /* Assign a hopefully unique, locally administered etheraddr. */ eaddr[0] = 0x02; + eaddr[1] = (uint8_t)(arc4random() % 0xff); + eaddr[2] = (uint8_t)(arc4random() % 0xff); eaddr[3] = (ifp->if_index >> 8) & 0xff; eaddr[4] = ifp->if_index & 0xff; eaddr[5] = 0x0b; @@ -817,6 +819,8 @@ epair_clone_create(struct if_clone *ifc, char *name, size_t len, caddr_t params) ifp->if_snd.ifq_maxlen = ifqmaxlen; /* Assign a hopefully unique, locally administered etheraddr. */ eaddr[0] = 0x02; + eaddr[1] = (uint8_t)(arc4random() % 0xff); + eaddr[2] = (uint8_t)(arc4random() % 0xff); eaddr[3] = (ifp->if_index >> 8) & 0xff; eaddr[4] = ifp->if_index & 0xff; eaddr[5] = 0x0a; >Release-Note: >Audit-Trail: >Unformatted:
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