Date: Tue, 14 Mar 2017 06:00:44 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r315225 - in head: lib/libc/gen sys/libkern Message-ID: <201703140600.v2E60iq5067343@repo.freebsd.org>
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Author: delphij Date: Tue Mar 14 06:00:44 2017 New Revision: 315225 URL: https://svnweb.freebsd.org/changeset/base/315225 Log: Discard first 3072 bytes of RC4 keystream, this is a bandaid that allows us to work on switching to a more modern PRNG. Submitted by: Steven Chamberlain <steven pyro eu org> Approved by: so Modified: head/lib/libc/gen/arc4random.c head/sys/libkern/arc4random.c Modified: head/lib/libc/gen/arc4random.c ============================================================================== --- head/lib/libc/gen/arc4random.c Tue Mar 14 02:13:59 2017 (r315224) +++ head/lib/libc/gen/arc4random.c Tue Mar 14 06:00:44 2017 (r315225) @@ -160,7 +160,7 @@ arc4_stir(void) * Discard early keystream, as per recommendations in: * "(Not So) Random Shuffles of RC4" by Ilya Mironov. */ - for (i = 0; i < 1024; i++) + for (i = 0; i < 3072; i++) (void)arc4_getbyte(); arc4_count = 1600000; } Modified: head/sys/libkern/arc4random.c ============================================================================== --- head/sys/libkern/arc4random.c Tue Mar 14 02:13:59 2017 (r315224) +++ head/sys/libkern/arc4random.c Tue Mar 14 06:00:44 2017 (r315225) @@ -84,11 +84,11 @@ arc4_randomstir(struct arc4_s* arc4) /* * Throw away the first N words of output, as suggested in the * paper "Weaknesses in the Key Scheduling Algorithm of RC4" - * by Fluher, Mantin, and Shamir. (N = 256 in our case.) + * by Fluher, Mantin, and Shamir. (N = 768 in our case.) * * http://dl.acm.org/citation.cfm?id=646557.694759 */ - for (n = 0; n < 256*4; n++) + for (n = 0; n < 768*4; n++) arc4_randbyte(arc4); mtx_unlock(&arc4->mtx);
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