Date: Sun, 20 Jan 2002 19:55:31 +0000 From: Mark Murray <mark@grondar.za> To: "Andrey A. Chernov" <ache@nagual.pp.ru> Cc: des@freebsd.org, current@freebsd.org Subject: Re: Step1, pam_unix srandomdev fix for review Message-ID: <200201201955.g0KJtVt32805@grimreaper.grondar.org> In-Reply-To: <20020120185334.GA23348@nagual.pp.ru> ; from "Andrey A. Chernov" <ache@nagual.pp.ru> "Sun, 20 Jan 2002 21:53:34 %2B0300." References: <20020120185334.GA23348@nagual.pp.ru>
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> Bug: > srandomdev() can't be used in libraries because it touch internal RNG > state which may be used by user program which not want true randomness but > pseudo one. > > Fix: > srandomdev() removed, random() replaced by arc4random() which initialize > itself from true randomness automatically. This works, but strikes me as overkill. This is salt, not cryptographic randomness, so 'srandom(junk)' is most likely better as a replacement for srandomdev() (where 'junk' can be time(), pid or anything similar). Salt's purpose is to make pre-computing a dictionary infeasable from the pure space perspective. M > --- pam_unix.c.old Sat Jan 19 21:29:49 2002 > +++ pam_unix.c Sun Jan 20 21:42:47 2002 > @@ -502,15 +502,14 @@ > syslog(LOG_ERR, "cannot set password cipher"); > login_close(lc); > /* Salt suitable for anything */ > - srandomdev(); > gettimeofday(&tv, 0); > - to64(&salt[0], random(), 3); > + to64(&salt[0], arc4random(), 3); > to64(&salt[3], tv.tv_usec, 3); > to64(&salt[6], tv.tv_sec, 2); > - to64(&salt[8], random(), 5); > - to64(&salt[13], random(), 5); > - to64(&salt[17], random(), 5); > - to64(&salt[22], random(), 5); > + to64(&salt[8], arc4random(), 5); > + to64(&salt[13], arc4random(), 5); > + to64(&salt[17], arc4random(), 5); > + to64(&salt[22], arc4random(), 5); > salt[27] = '\0'; > > pwd->pw_passwd = crypt(pass, salt); > @@ -596,15 +595,14 @@ > syslog(LOG_ERR, "cannot set password cipher"); > login_close(lc); > /* Salt suitable for anything */ > - srandomdev(); > gettimeofday(&tv, 0); > - to64(&salt[0], random(), 3); > + to64(&salt[0], arc4random(), 3); > to64(&salt[3], tv.tv_usec, 3); > to64(&salt[6], tv.tv_sec, 2); > - to64(&salt[8], random(), 5); > - to64(&salt[13], random(), 5); > - to64(&salt[17], random(), 5); > - to64(&salt[22], random(), 5); > + to64(&salt[8], arc4random(), 5); > + to64(&salt[13], arc4random(), 5); > + to64(&salt[17], arc4random(), 5); > + to64(&salt[22], arc4random(), 5); > salt[27] = '\0'; > > if (suser_override) > -- > Andrey A. Chernov > http://ache.pp.ru/ -- o Mark Murray \_ FreeBSD Services Limited O.\_ Warning: this .sig is umop ap!sdn To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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