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X Strike Force X.Org X11 SVN commit: r1372 - in branches/modular/app/xutils/debian: . patches



Author: dnusinow
Date: 2006-03-04 19:18:44 -0500 (Sat, 04 Mar 2006)
New Revision: 1372

Added:
   branches/modular/app/xutils/debian/patches/01_sessreg_implement_hostname_hashing.diff
Modified:
   branches/modular/app/xutils/debian/changelog
   branches/modular/app/xutils/debian/patches/series
Log:
* Port patches from trunk
  + general/085_sessreg_implement_hostname_hashing.diff


Modified: branches/modular/app/xutils/debian/changelog
===================================================================
--- branches/modular/app/xutils/debian/changelog	2006-03-05 00:08:04 UTC (rev 1371)
+++ branches/modular/app/xutils/debian/changelog	2006-03-05 00:18:44 UTC (rev 1372)
@@ -2,8 +2,10 @@
 
   [ David Nusinow ]
   * Depend on xutils-dev
+  * Port patches from trunk
+    + general/085_sessreg_implement_hostname_hashing.diff
 
- -- David Nusinow <dnusinow@debian.org>  Thu, 23 Feb 2006 20:46:23 -0500
+ -- David Nusinow <dnusinow@debian.org>  Sat,  4 Mar 2006 19:18:04 -0500
 
 xutils (1:1.0.1-1) experimental; urgency=low
 

Added: branches/modular/app/xutils/debian/patches/01_sessreg_implement_hostname_hashing.diff
===================================================================
--- branches/modular/app/xutils/debian/patches/01_sessreg_implement_hostname_hashing.diff	2006-03-05 00:08:04 UTC (rev 1371)
+++ branches/modular/app/xutils/debian/patches/01_sessreg_implement_hostname_hashing.diff	2006-03-05 00:18:44 UTC (rev 1372)
@@ -0,0 +1,204 @@
+$Id: 085_sessreg_implement_hostname_hashing.diff 689 2005-10-19 22:11:30Z dnusinow $
+
+The sessreg program assumes that hostnames in utmp entries are unique in
+the last four characters.  When two entries are "test:0" and "fist:0", for
+example, this assumption fails.
+
+Rectify this problem by hashing the entire hostname field from the utmp
+entry, so that we can tell unlike hostnames apart with much greater
+reliability.  There is still a possiblility of one hash collision in 2^32.
+
+This patch by Maximiliano Curia and Damián Viano, using a public-domain
+hash algorithm by Bob Jenkins.
+
+Not submitted to XFree86.
+
+Index: sessreg-X11R7.0-1.0.0/sessreg.c
+===================================================================
+--- sessreg-X11R7.0-1.0.0/sessreg.c.orig	2005-10-18 19:45:25.000000000 -0400
++++ sessreg-X11R7.0-1.0.0/sessreg.c	2005-10-18 21:36:02.000000000 -0400
+@@ -182,6 +182,18 @@
+ 		       const char *host, Time_t date, int addp);
+ #endif
+ 
++#ifdef SYSV
++/* used for hashing ut_id */
++typedef  unsigned long  int  ub4;   /* unsigned 4-byte quantities */
++typedef  unsigned       char ub1;   /* unsigned 1-byte quantities */
++
++#define hashsize(n) ((ub4)1<<(n))
++#define hashmask(n) (hashsize(n)-1)
++
++ub4 hash(register ub1 *k, register ub4 length, register ub4 initval);
++
++#endif
++
+ int	wflag, uflag, lflag;
+ char	*wtmp_file, *utmp_file, *line;
+ #ifdef USE_UTMPX
+@@ -469,21 +481,23 @@
+ 		bzero (u->ut_name, sizeof (u->ut_name));
+ #ifdef SYSV
+ 	if (line) {
+-		int	i;
+ 		/*
+-		 * this is a bit crufty, but
+-		 * follows the apparent conventions in
+-		 * the ttys file.  ut_id is only 4 bytes
+-		 * long, and the last 4 bytes of the line
+-		 * name are written into it, left justified.
++		 * The ut_id is 4 bytes long.  We make a hash of the line
++		 * received, preceding it by ":" to prevent clashing with
++		 * other ut_ids.
+ 		 */
+-		i = strlen (line);
+-		if (i >= sizeof (u->ut_id))
+-			i -= sizeof (u->ut_id);
+-		else
+-			i = 0;
+-		(void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));
++		ub4 h;
++		u->ut_id[0]=':';
++		h = hash(line, strlen(line),0x9e3779b9);
++		h = (h & hashmask((sizeof(u->ut_id)-sizeof(char))*8));
++		(void) strncpy (u->ut_id + 1,(char *) &h,  sizeof (u->ut_id)-sizeof(char));
+ 	} else
++		/*
++		 * From utmp(5):
++		 * Clearing ut_id may result in race conditions leading to corrupted
++		 * utmp entries and and potential security holes.
++		 */
++		/* TODO: CHECK this  */
+ 		bzero (u->ut_id, sizeof (u->ut_id));
+ 	if (addp) {
+ 		u->ut_pid = getppid ();
+@@ -722,3 +736,129 @@
+ 		return freeslot;
+ }
+ #endif
++
++#ifdef SYSV
++/*
++--------------------------------------------------------------------
++mix -- mix 3 32-bit values reversibly.
++For every delta with one or two bits set, and the deltas of all three
++  high bits or all three low bits, whether the original value of a,b,c
++  is almost all zero or is uniformly distributed,
++* If mix() is run forward or backward, at least 32 bits in a,b,c
++  have at least 1/4 probability of changing.
++* If mix() is run forward, every bit of c will change between 1/3 and
++  2/3 of the time.  (Well, 22/100 and 78/100 for some 2-bit deltas.)
++mix() was built out of 36 single-cycle latency instructions in a
++  structure that could supported 2x parallelism, like so:
++      a -= b;
++      a -= c; x = (c>>13);
++      b -= c; a ^= x;
++      b -= a; x = (a<<8);
++      c -= a; b ^= x;
++      c -= b; x = (b>>13);
++      ...
++  Unfortunately, superscalar Pentiums and Sparcs can't take advantage
++  of that parallelism.  They've also turned some of those single-cycle
++  latency instructions into multi-cycle latency instructions.  Still,
++  this is the fastest good hash I could find.  There were about 2^^68
++  to choose from.  I only looked at a billion or so.
++--------------------------------------------------------------------
++*/
++#define mix(a,b,c) \
++{ \
++  a -= b; a -= c; a ^= (c>>13); \
++  b -= c; b -= a; b ^= (a<<8); \
++  c -= a; c -= b; c ^= (b>>13); \
++  a -= b; a -= c; a ^= (c>>12);  \
++  b -= c; b -= a; b ^= (a<<16); \
++  c -= a; c -= b; c ^= (b>>5); \
++  a -= b; a -= c; a ^= (c>>3);  \
++  b -= c; b -= a; b ^= (a<<10); \
++  c -= a; c -= b; c ^= (b>>15); \
++}
++
++/*
++--------------------------------------------------------------------
++hash() -- hash a variable-length key into a 32-bit value
++  k       : the key (the unaligned variable-length array of bytes)
++  len     : the length of the key, counting by bytes
++  initval : can be any 4-byte value
++Returns a 32-bit value.  Every bit of the key affects every bit of
++the return value.  Every 1-bit and 2-bit delta achieves avalanche.
++About 6*len+35 instructions.
++
++The best hash table sizes are powers of 2.  There is no need to do
++mod a prime (mod is sooo slow!).  If you need less than 32 bits,
++use a bitmask.  For example, if you need only 10 bits, do
++  h = (h & hashmask(10));
++In which case, the hash table should have hashsize(10) elements.
++
++If you are hashing n strings (ub1 **)k, do it like this:
++  for (i=0, h=0; i<n; ++i) h = hash( k[i], len[i], h);
++
++By Bob Jenkins, 1996.  bob_jenkins@burtleburtle.net.  You may use this
++code any way you wish, private, educational, or commercial.  It's free.
++
++[On 27 May 2004, Bob Jenkins further clarified the above statement.
++
++  From: Bob Jenkins <bob_jenkins@burtleburtle.net>
++  Date: Thu, 27 May 2004 22:33:06 -0700
++  To: Margarita Manterola <marga@marga.com.ar>
++  Subject: Re: Hash function
++
++  The algorithm is public domain.  I ask that I be referenced as the
++  source of the algorithm, but I can't enforce that, since being public
++  domain means I've reserved no rights at all.
++
++-- Branden Robinson, 2004-06-06]
++
++See http://burtleburtle.net/bob/hash/evahash.html
++Use for hash table lookup, or anything where one collision in 2^^32 is
++acceptable.  Do NOT use for cryptographic purposes.
++--------------------------------------------------------------------
++*/
++
++ub4
++hash(register ub1 *k, register ub4 length, register ub4 initval)
++{
++   register ub4 a,b,c,len;
++
++   /* Set up the internal state */
++   len = length;
++   a = b = 0x9e3779b9;  /* the golden ratio; an arbitrary value */
++   c = initval;         /* the previous hash value */
++
++   /*---------------------------------------- handle most of the key */
++   while (len >= 12)
++   {
++      a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24));
++      b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24));
++      c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24));
++      mix(a,b,c);
++      k += 12; len -= 12;
++   }
++
++   /*------------------------------------- handle the last 11 bytes */
++   c += length;
++   switch(len)              /* all the case statements fall through */
++   {
++   case 11: c+=((ub4)k[10]<<24);
++   case 10: c+=((ub4)k[9]<<16);
++   case 9 : c+=((ub4)k[8]<<8);
++      /* the first byte of c is reserved for the length */
++   case 8 : b+=((ub4)k[7]<<24);
++   case 7 : b+=((ub4)k[6]<<16);
++   case 6 : b+=((ub4)k[5]<<8);
++   case 5 : b+=k[4];
++   case 4 : a+=((ub4)k[3]<<24);
++   case 3 : a+=((ub4)k[2]<<16);
++   case 2 : a+=((ub4)k[1]<<8);
++   case 1 : a+=k[0];
++     /* case 0: nothing left to add */
++   }
++   mix(a,b,c);
++   /*-------------------------------------------- report the result */
++   return c;
++}
++
++#endif

Modified: branches/modular/app/xutils/debian/patches/series
===================================================================
--- branches/modular/app/xutils/debian/patches/series	2006-03-05 00:08:04 UTC (rev 1371)
+++ branches/modular/app/xutils/debian/patches/series	2006-03-05 00:18:44 UTC (rev 1372)
@@ -0,0 +1 @@
+01_sessreg_implement_hostname_hashing.diff -p0



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