Date: Fri, 06 Oct 2017 01:24:51 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 222807] PURE entropy sources are harvested but not mixed in. Also, min-entropy low per SP800-90B measurements Message-ID: <bug-222807-8-GDXSmXwx1m@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-222807-8@https.bugs.freebsd.org/bugzilla/> References: <bug-222807-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D222807 --- Comment #5 from W. Dean Freeman <badfilemagic@gmail.com> --- (In reply to Conrad Meyer from comment #3) The core of the problem with the pure sources was, in random_harvest_queue = and random_harvest_direct, the value hc_source_mask is checked to see whether t= he source bit is set. If it isn't, the functions bail out before they actually either add an entry to the harvest ring buffer (in the case of random_harvest_queue) or feed into ra_process_event (ie, random_fortuna_process_event). Thus, entropy is being harvested, by virtue of the fact that sources push, rather than having /dev/random pull from them. However, the results of the = push were not being mixed in. Additionally, there was no way via sysctl or any other means to set the bit= for the source. We have added code which will ensure the bit gets set on register for sourc= es which do register as entropy sources (which is really just RDRND and VIA Padlock), however many pure sources, such as RANDOM_PURE_BROADCOM, which is= the source for the trng in Raspberry Pi devices, don't register. They use random_harvest_queue. The point of the patch is to correct that. Additionally, it allows showing = the value in sysctl. For sources other than RDRND and VIA, there isn't an additional way beyond the mask to see whether the source is actually turned= on or not, since they don't register. The patch corrects the behavior and all= ows the operator to ensure that it is set. --=20 You are receiving this mail because: You are the assignee for the bug.=
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