From owner-freebsd-security@FreeBSD.ORG Wed Sep 19 22:08:20 2012 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 664) id 7B8D51065672; Wed, 19 Sep 2012 22:08:20 +0000 (UTC) Date: Wed, 19 Sep 2012 15:08:19 -0700 From: David O'Brien To: Mark Murray Message-ID: <20120919220819.GB25606@dragon.NUXI.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: FreeBSD 10.0-CURRENT X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? User-Agent: Mutt/1.5.20 (2009-06-14) Cc: Arthur Mesh , Ian Lepore , Doug Barton , Ben Laurie , freebsd-security@freebsd.org, RW Subject: Re: Proposed fix; stage 1 (Was: svn commit: r239569 - head/etc/rc.d) X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: obrien@freebsd.org List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Sep 2012 22:08:20 -0000 On Sun, Sep 16, 2012 at 05:21:21PM +0100, Mark Murray wrote: > Tweeks along the way may include reverting to the original intent of > starting the PRNG blocked, and only unblocking once reseeded. I hope I'm testing this incorrectly, but I think we've managed to break this over the years. 1. Putting: entropy_file="NO" entropy_dir="NO" entropy_save_sz="0" # Size of the entropy cache files. entropy_save_num="0" # Number of entropy cache files to save. harvest_interrupt="NO" # Entropy device harvests interrupt randomness harvest_ethernet="NO" # Entropy device harvests ethernet randomness harvest_p_to_p="NO" # Entropy device harvests point-to-point randomness in /etc/rc.conf 2. Commenting out "better_than_nothing": Index: initrandom =================================================================== --- initrandom (revision 240709) +++ initrandom (working copy) @@ -77,7 +77,7 @@ initrandom_start() ;; esac - better_than_nothing + #better_than_nothing echo -n ' kickstart' fi 3. Boot single user and delete ${entropy_file} and ${entropy_dir}/* 4. Adding this patch (which I'd like to commit (but not changing the defaults)): ----------%<----------%<----------%<----------%<----------%<---------- Index: sys/dev/random/randomdev_soft.c =================================================================== --- sys/dev/random/randomdev_soft.c (revision 240694) +++ sys/dev/random/randomdev_soft.c (working copy) @@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include #include @@ -72,7 +73,7 @@ struct random_systat random_yarrow = { .write = random_yarrow_write, .poll = random_yarrow_poll, .reseed = random_yarrow_flush_reseed, - .seeded = 1, + .seeded = 0, }; MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers"); @@ -85,7 +86,7 @@ struct mtx harvest_mtx; /* Lockable FIFO queue holding entropy buffers */ struct entropyfifo { - int count; + unsigned int count; STAILQ_HEAD(harvestlist, harvest) head; }; @@ -97,6 +98,9 @@ static struct entropyfifo emptyfifo; /* Harvested entropy */ static struct entropyfifo harvestfifo[ENTROPYSOURCE]; +/* Count processed categories of randomness. */ +static unsigned long e_src_cnt[ENTROPYSOURCE]; + /* <0 to end the kthread, 0 to let it run, 1 to flush the harvest queues */ static int random_kthread_control = 0; @@ -114,6 +118,34 @@ random_check_boolean(SYSCTL_HANDLER_ARGS return sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); } +static int +sysctl_random_sys_entropy_processed(SYSCTL_HANDLER_ARGS) +{ + struct sbuf sb; + int error; + + sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND); + sbuf_printf(&sb, +"write=%lu/%u, keyboard=%lu/%u, mouse=%lu/%u, net=%lu/%u, interrupt=%lu/%u, pure=%lu/%u", + e_src_cnt[RANDOM_WRITE], + harvestfifo[RANDOM_WRITE].count, + e_src_cnt[RANDOM_KEYBOARD], + harvestfifo[RANDOM_KEYBOARD].count, + e_src_cnt[RANDOM_MOUSE], + harvestfifo[RANDOM_MOUSE].count, + e_src_cnt[RANDOM_NET], + harvestfifo[RANDOM_NET].count, + e_src_cnt[RANDOM_INTERRUPT], + harvestfifo[RANDOM_INTERRUPT].count, + e_src_cnt[RANDOM_PURE], + harvestfifo[RANDOM_PURE].count); + sbuf_trim(&sb); + sbuf_finish(&sb); + error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req); + sbuf_delete(&sb); + return (error); +} + /* ARGSUSED */ void random_yarrow_init(void) @@ -138,7 +170,7 @@ random_yarrow_init(void) SYSCTL_ADD_PROC(&random_clist, SYSCTL_CHILDREN(random_sys_o), OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW, - &random_systat.seeded, 1, random_check_boolean, "I", + &random_systat.seeded, 0, random_check_boolean, "I", "Seeded State"); random_sys_harvest_o = SYSCTL_ADD_NODE(&random_clist, @@ -166,6 +198,10 @@ random_yarrow_init(void) OID_AUTO, "swi", CTLTYPE_INT | CTLFLAG_RW, &harvest.swi, 0, random_check_boolean, "I", "Harvest SWI entropy"); + SYSCTL_ADD_PROC(&random_clist, SYSCTL_CHILDREN(random_sys_harvest_o), + OID_AUTO, "entropy_processed", CTLTYPE_STRING | CTLFLAG_RD, + NULL, 0, sysctl_random_sys_entropy_processed, "A", + "Number of harvested/queued entropy sources"); /* Initialise the harvest fifos */ STAILQ_INIT(&emptyfifo.head); @@ -263,8 +299,10 @@ random_kthread(void *arg __unused) */ if (!STAILQ_EMPTY(&local_queue)) { mtx_unlock_spin(&harvest_mtx); - STAILQ_FOREACH(event, &local_queue, next) + STAILQ_FOREACH(event, &local_queue, next) { random_process_event(event); + e_src_cnt[event->source]++; + } mtx_lock_spin(&harvest_mtx); STAILQ_CONCAT(&emptyfifo.head, &local_queue); emptyfifo.count += local_count; Index: sys/dev/random/harvest.c =================================================================== --- sys/dev/random/harvest.c (revision 240694) +++ sys/dev/random/harvest.c (working copy) @@ -48,7 +48,12 @@ __FBSDID("$FreeBSD$"); static int read_random_phony(void *, int); /* Structure holding the desired entropy sources */ -struct harvest_select harvest = { 1, 1, 1, 0 }; +struct harvest_select harvest = { + 0, /*ethernet*/ + 0, /*pt2pt*/ + 0, /*intr*/ + 0, /*swi*/ +}; static int warned = 0; /* hold the address of the routine which is actually called if @@ -84,6 +89,12 @@ random_yarrow_deinit_harvester(void) * XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle * counters are built in, but on older hardware it will do a real time clock * read which can be quite expensive. + * + * @entropy Buffer of 'count' bytes of potential entropy. + * @count Number of bytes in 'buffer' to process. + * @bits Estimated number of bits of entropy in 'buffer'. + * @frac Estimated number of fractional bits entropy in 'buffer'. + * @origin Origin where this entropy was gathered. */ void random_harvest(void *entropy, u_int count, u_int bits, u_int frac, ----------%<----------%<----------%<----------%<----------%<---------- 5. Still lets me boot multi-user and login: ngoc# sysctl kern.random kern.random.yarrow.gengateinterval: 10 kern.random.yarrow.bins: 10 kern.random.yarrow.fastthresh: 192 kern.random.yarrow.slowthresh: 256 kern.random.yarrow.slowoverthresh: 2 kern.random.sys.seeded: 0 kern.random.sys.harvest.ethernet: 0 kern.random.sys.harvest.point_to_point: 0 kern.random.sys.harvest.interrupt: 0 kern.random.sys.harvest.swi: 0 kern.random.sys.harvest.entropy_processed: write=0/0, keyboard=0/0, mouse=0/0, net=0/0, interrupt=0/0, pure=0/0 Also, I'm having trouble finding the source for 'swi' harvesting. Do you know where it is? -- -- David (obrien@FreeBSD.org)