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 <[EMAIL PROTECTED]> Thu, 23 Feb 2006 20:46:23 -0500
+ -- David Nusinow <[EMAIL PROTECTED]> 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. [EMAIL PROTECTED] 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 <[EMAIL PROTECTED]>
++ Date: Thu, 27 May 2004 22:33:06 -0700
++ To: Margarita Manterola <[EMAIL PROTECTED]>
++ 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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