From: larrybr <larrybr@noemail.net>
Date: Mon, 15 May 2023 03:48:48 +0000 (+0000)
Subject: Make generate_series() correct on ones complement ALUs and acceptable to UBSAN.
X-Git-Tag: version-3.42.0~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b579db6d5cffd26f89891c18c9a1cdd2abcd85ed;p=thirdparty%2Fsqlite.git

Make generate_series() correct on ones complement ALUs and acceptable to UBSAN.

FossilOrigin-Name: 4c5cd3e6968c44749b7663beee790969b41d247b9201b771ef90cbb03d09108f
---

diff --git a/ext/misc/series.c b/ext/misc/series.c
index 9f864fd1ab..4e75fe9044 100644
--- a/ext/misc/series.c
+++ b/ext/misc/series.c
@@ -109,7 +109,17 @@ static sqlite3_int64 genSeqMember(sqlite3_int64 smBase,
   if( ix>=(sqlite3_uint64)LLONG_MAX ){
     /* Get ix into signed i64 range. */
     ix -= (sqlite3_uint64)LLONG_MAX;
-    smBase += LLONG_MAX * smStep;
+    /* With 2's complement ALU, this next can be 1 step, but is split into
+     * 2 for UBSAN's satisfaction (and hypothetical 1's complement ALUs.) */
+    smBase += (LLONG_MAX/2) * smStep;
+    smBase += (LLONG_MAX - LLONG_MAX/2) * smStep;
+  }
+  /* Under UBSAN (or on 1's complement machines), must do this last term
+   * in steps to avoid the dreaded (and harmless) signed multiply overlow. */
+  if( ix>=2 ){
+    sqlite3_int64 ix2 = (sqlite3_int64)ix/2;
+    smBase += ix2*smStep;
+    ix -= ix2;
   }
   return smBase + ((sqlite3_int64)ix)*smStep;
 }
@@ -132,11 +142,21 @@ typedef struct SequenceSpec {
 ** given initialized iBase, iTerm and iStep values. Sequence is
 ** initialized per given isReversing. Other members are computed.
 */
-void setupSequence( SequenceSpec *pss ){
+static void setupSequence( SequenceSpec *pss ){
   pss->uSeqIndexMax = 0;
   pss->isNotEOF = 0;
+  int bSameSigns = (pss->iBase < 0)==(pss->iTerm < 0);
   if( pss->iTerm < pss->iBase ){
-    sqlite3_uint64 nuspan = (sqlite3_uint64)(pss->iBase-pss->iTerm);
+    sqlite3_uint64 nuspan = 0;
+    if( bSameSigns ){
+      nuspan = (sqlite3_uint64)(pss->iBase - pss->iTerm);
+    }else{
+      /* Under UBSAN (or on 1's complement machines), must do this in steps.
+       * In this clause, iBase>=0 and iTerm<0 . */
+      nuspan = 1;
+      nuspan += pss->iBase;
+      nuspan += -(pss->iTerm+1);
+    }
     if( pss->iStep<0 ){
       pss->isNotEOF = 1;
       if( nuspan==ULONG_MAX ){
@@ -146,7 +166,16 @@ void setupSequence( SequenceSpec *pss ){
       }
     }
   }else if( pss->iTerm > pss->iBase ){
-    sqlite3_uint64 puspan = (sqlite3_uint64)(pss->iTerm-pss->iBase);
+    sqlite3_uint64 puspan = 0;
+    if( bSameSigns ){
+      puspan = (sqlite3_uint64)(pss->iTerm - pss->iBase);
+    }else{
+      /* Under UBSAN (or on 1's complement machines), must do this in steps.
+       * In this clause, iTerm>=0 and iBase<0 . */
+      puspan = 1;
+      puspan += pss->iTerm;
+      puspan += -(pss->iBase+1);
+    }
     if( pss->iStep>0 ){
       pss->isNotEOF = 1;
       pss->uSeqIndexMax = puspan/pss->iStep;
@@ -166,7 +195,7 @@ void setupSequence( SequenceSpec *pss ){
 ** Leave its state to either yield next value or be at EOF.
 ** Return whether there is a next value, or 0 at EOF.
 */
-int progressSequence( SequenceSpec *pss ){
+static int progressSequence( SequenceSpec *pss ){
   if( !pss->isNotEOF ) return 0;
   if( pss->isReversing ){
     if( pss->uSeqIndexNow > 0 ){
@@ -301,13 +330,13 @@ static int seriesColumn(
 }
 
 /*
-** Return the rowid for the current row. In this implementation, the
-** first row returned is assigned rowid value 1, and each subsequent
-** row a value 1 more than that of the previous.
+** Return the rowid for the current row, logically equivalent to n+1 where
+** "n" is the ascending integer in the aforesaid production definition.
 */
 static int seriesRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
   series_cursor *pCur = (series_cursor*)cur;
-  *pRowid = ((sqlite3_int64)pCur->ss.uSeqIndexNow + 1);
+  sqlite3_uint64 n = pCur->ss.uSeqIndexNow;
+  *pRowid = (sqlite3_int64)((n<0xffffffffffffffff)? n+1 : 0);
   return SQLITE_OK;
 }
 
diff --git a/manifest b/manifest
index dabff2e181..e9d6c07165 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C As\sevidenced\sby\s[forum:/forumpost/f3f546025a|forum\spost\sf3f546025a],\sthe\nnew\sRIGHT\sJOIN\srelated\srestriction\son\sthe\spush-down\soptimization\simplemented\nby\s[da3fba18742b6e0b]\salso\sneeds\sto\sapply\sto\sthe\sautomatic\sindex\n(a.k.a.\shash-join)\soptimization\sand\sto\sthe\sBloom\sfilter\soptimization.\nComputation\sof\sthe\srestriction\sis\snow\nmoved\sinto\sthe\ssqlite3ExprIsSingleTableConstraint()\sroutine.
-D 2023-05-15T02:06:35.229
+C Make\sgenerate_series()\scorrect\son\sones\scomplement\sALUs\sand\sacceptable\sto\sUBSAN.
+D 2023-05-15T03:48:48.598
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -307,7 +307,7 @@ F ext/misc/regexp.c 4bdd0045912f81c84908bd535ec5ad3b1c8540b4287c70ab840709636240
 F ext/misc/remember.c add730f0f7e7436cd15ea3fd6a90fd83c3f706ab44169f7f048438b7d6baa69c
 F ext/misc/rot13.c 51ac5f51e9d5fd811db58a9c23c628ad5f333c173f1fc53c8491a3603d38556c
 F ext/misc/scrub.c 2a44b0d44c69584c0580ad2553f6290a307a49df4668941d2812135bfb96a946
-F ext/misc/series.c 37d27377684d3ea14177540d2f2767163197611eaba905790c96abd4ab552cd3
+F ext/misc/series.c 387381db0fe3329e9ea7d46df87c98c25b95c39b11fa9999a24dcbe6b2779e52
 F ext/misc/sha1.c 4011aef176616872b2a0d5bccf0ecfb1f7ce3fe5c3d107f3a8e949d8e1e3f08d
 F ext/misc/shathree.c 543af7ce71d391cd3a9ab6924a6a1124efc63211fd0f2e240dc4b56077ba88ac
 F ext/misc/showauth.c 732578f0fe4ce42d577e1c86dc89dd14a006ab52
@@ -2069,8 +2069,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
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 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P c5da16551619718bf649c517515261706843e11e131f0b99e1fd6927d0f7e238
-R 19526b8216d20a0f1da8af3749d5cbdb
-U drh
-Z 784c6c524217b70137b2b3907aa60981
+P 4902015dcf3869f08d9986e422faa231d9218a5e0fc59ba8df0f407e4eb3d605
+R 17307900605f9e82492f51004e8218f7
+U larrybr
+Z be454f9c1f92315357662a45ba347767
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index b9760a70bb..c9540c75e9 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-4902015dcf3869f08d9986e422faa231d9218a5e0fc59ba8df0f407e4eb3d605
\ No newline at end of file
+4c5cd3e6968c44749b7663beee790969b41d247b9201b771ef90cbb03d09108f
\ No newline at end of file