Fix further buffer overreads triggered by passing corrupt records to the sqlite_dbdat...

FossilOrigin-Name: dbc6a9f7f67256dea96d3245e7bec145ba65d64adf322e18f1f3ac9556b4e0b6

diff --git a/ext/misc/dbdata.c b/ext/misc/dbdata.c
index 88906513a73d61fc3029e7efa411cd4286daff50..4cbb96691f9aec2749e6dc4c1e1af9718df20cf1 100644 (file)
--- a/ext/misc/dbdata.c
+++ b/ext/misc/dbdata.c
@@ -495,6 +495,7 @@ static int dbdataNext(sqlite3_vtab_cursor *pCursor){
         int iHdr;
         int U, X;
         int nLocal;
+        int bNextPage = 0;
   
         switch( pCsr->aPage[iOff] ){
           case 0x02:
@@ -512,82 +513,104 @@ static int dbdataNext(sqlite3_vtab_cursor *pCursor){
         }
 
         if( pCsr->iCell>=pCsr->nCell ){
+          bNextPage = 1;
+        }else{
+  
+          iOff += 8 + nPointer + pCsr->iCell*2;
+          if( iOff>pCsr->nPage ){
+            bNextPage = 1;
+          }else{
+            iOff = get_uint16(&pCsr->aPage[iOff]);
+          }
+    
+          /* For an interior node cell, skip past the child-page number */
+          iOff += nPointer;
+    
+          /* Load the "byte of payload including overflow" field */
+          if( bNextPage || iOff>pCsr->nPage ){
+            bNextPage = 1;
+          }else{
+            iOff += dbdataGetVarint(&pCsr->aPage[iOff], &nPayload);
+          }
+    
+          /* If this is a leaf intkey cell, load the rowid */
+          if( bHasRowid && !bNextPage && iOff<pCsr->nPage ){
+            iOff += dbdataGetVarint(&pCsr->aPage[iOff], &pCsr->iIntkey);
+          }
+    
+          /* Figure out how much data to read from the local page */
+          U = pCsr->nPage;
+          if( bHasRowid ){
+            X = U-35;
+          }else{
+            X = ((U-12)*64/255)-23;
+          }
+          if( nPayload<=X ){
+            nLocal = nPayload;
+          }else{
+            int M, K;
+            M = ((U-12)*32/255)-23;
+            K = M+((nPayload-M)%(U-4));
+            if( K<=X ){
+              nLocal = K;
+            }else{
+              nLocal = M;
+            }
+          }
+
+          if( bNextPage || nLocal+iOff>pCsr->nPage ){
+            bNextPage = 1;
+          }else{
+
+            /* Allocate space for payload. And a bit more to catch small buffer
+            ** overruns caused by attempting to read a varint or similar from 
+            ** near the end of a corrupt record.  */
+            pCsr->pRec = (u8*)sqlite3_malloc64(nPayload+100);
+            if( pCsr->pRec==0 ) return SQLITE_NOMEM;
+            memset(pCsr->pRec, 0, nPayload+100);
+            pCsr->nRec = nPayload;
+
+            /* Load the nLocal bytes of payload */
+            memcpy(pCsr->pRec, &pCsr->aPage[iOff], nLocal);
+            iOff += nLocal;
+
+            /* Load content from overflow pages */
+            if( nPayload>nLocal ){
+              sqlite3_int64 nRem = nPayload - nLocal;
+              unsigned int pgnoOvfl = get_uint32(&pCsr->aPage[iOff]);
+              while( nRem>0 ){
+                u8 *aOvfl = 0;
+                int nOvfl = 0;
+                int nCopy;
+                rc = dbdataLoadPage(pCsr, pgnoOvfl, &aOvfl, &nOvfl);
+                assert( rc!=SQLITE_OK || nOvfl==pCsr->nPage );
+                if( rc!=SQLITE_OK ) return rc;
+
+                nCopy = U-4;
+                if( nCopy>nRem ) nCopy = nRem;
+                memcpy(&pCsr->pRec[nPayload-nRem], &aOvfl[4], nCopy);
+                nRem -= nCopy;
+
+                pgnoOvfl = get_uint32(aOvfl);
+                sqlite3_free(aOvfl);
+              }
+            }
+    
+            iHdr = dbdataGetVarint(pCsr->pRec, &nHdr);
+            pCsr->nHdr = nHdr;
+            pCsr->pHdrPtr = &pCsr->pRec[iHdr];
+            pCsr->pPtr = &pCsr->pRec[pCsr->nHdr];
+            pCsr->iField = (bHasRowid ? -1 : 0);
+          }
+        }
+
+        if( bNextPage ){
           sqlite3_free(pCsr->aPage);
           pCsr->aPage = 0;
           if( pCsr->bOnePage ) return SQLITE_OK;
           pCsr->iPgno++;
           continue;
         }
-  
-        iOff += 8 + nPointer + pCsr->iCell*2;
-        iOff = get_uint16(&pCsr->aPage[iOff]);
-  
-        /* For an interior node cell, skip past the child-page number */
-        iOff += nPointer;
-  
-        /* Load the "byte of payload including overflow" field */
-        iOff += dbdataGetVarint(&pCsr->aPage[iOff], &nPayload);
-  
-        /* If this is a leaf intkey cell, load the rowid */
-        if( bHasRowid ){
-          iOff += dbdataGetVarint(&pCsr->aPage[iOff], &pCsr->iIntkey);
-        }
-  
-        /* Allocate space for payload */
-        pCsr->pRec = (u8*)sqlite3_malloc64(nPayload);
-        if( pCsr->pRec==0 ) return SQLITE_NOMEM;
-        pCsr->nRec = nPayload;
-  
-        U = pCsr->nPage;
-        if( bHasRowid ){
-          X = U-35;
-        }else{
-          X = ((U-12)*64/255)-23;
-        }
-        if( nPayload<=X ){
-          nLocal = nPayload;
-        }else{
-          int M, K;
-          M = ((U-12)*32/255)-23;
-          K = M+((nPayload-M)%(U-4));
-          if( K<=X ){
-            nLocal = K;
-          }else{
-            nLocal = M;
-          }
-        }
-  
-        /* Load the nLocal bytes of payload */
-        memcpy(pCsr->pRec, &pCsr->aPage[iOff], nLocal);
-        iOff += nLocal;
-  
-        /* Load content from overflow pages */
-        if( nPayload>nLocal ){
-          sqlite3_int64 nRem = nPayload - nLocal;
-          unsigned int pgnoOvfl = get_uint32(&pCsr->aPage[iOff]);
-          while( nRem>0 ){
-            u8 *aOvfl = 0;
-            int nOvfl = 0;
-            int nCopy;
-            rc = dbdataLoadPage(pCsr, pgnoOvfl, &aOvfl, &nOvfl);
-            assert( rc!=SQLITE_OK || nOvfl==pCsr->nPage );
-            if( rc!=SQLITE_OK ) return rc;
-  
-            nCopy = U-4;
-            if( nCopy>nRem ) nCopy = nRem;
-            memcpy(&pCsr->pRec[nPayload-nRem], &aOvfl[4], nCopy);
-            nRem -= nCopy;
-  
-            pgnoOvfl = get_uint32(aOvfl);
-            sqlite3_free(aOvfl);
-          }
-        }
-  
-        iHdr = dbdataGetVarint(pCsr->pRec, &nHdr);
-        pCsr->nHdr = nHdr;
-        pCsr->pHdrPtr = &pCsr->pRec[iHdr];
-        pCsr->pPtr = &pCsr->pRec[pCsr->nHdr];
-        pCsr->iField = (bHasRowid ? -1 : 0);
       }else{
         pCsr->iField++;
         if( pCsr->iField>0 ){

diff --git a/manifest b/manifest
index 4b83c71c583fec9c615929320b8f070a0317b417..83937eb82ee351aee396b2f5e71d82d17cd52ddc 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Have\s".recover"\shandle\scases\swhere\sthe\ssqlite_master\stable\scontains\smalformed\sSQL\sstatements.
-D 2019-05-09T14:15:19.691
+C Fix\sfurther\sbuffer\soverreads\striggered\sby\spassing\scorrupt\srecords\sto\sthe\ssqlite_dbdata\smodule.
+D 2019-05-09T15:07:46.363
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -284,7 +284,7 @@ F ext/misc/closure.c dbfd8543b2a017ae6b1a5843986b22ddf99ff126ec9634a2f4047cd14c8
 F ext/misc/completion.c cec672d40604075bb341a7f11ac48393efdcd90a979269b8fe7977ea62d0547f
 F ext/misc/compress.c dd4f8a6d0baccff3c694757db5b430f3bbd821d8686d1fc24df55cf9f035b189
 F ext/misc/csv.c 7f047aeb68f5802e7ce6639292095d622a488bb43526ed04810e0649faa71ceb
-F ext/misc/dbdata.c 1d3d1ebd23d3e4e5debbc54719376781e146626c2ee0b989b412b1a9c8ccdd37
+F ext/misc/dbdata.c db2674c3a5913a784a75a11d1e7905b14f6b81de1879d6e5fde4f0887f08decf
 F ext/misc/dbdump.c baf6e37447c9d6968417b1cd34cbedb0b0ab3f91b5329501d8a8d5be3287c336
 F ext/misc/eval.c 4b4757592d00fd32e44c7a067e6a0e4839c81a4d57abc4131ee7806d1be3104e
 F ext/misc/explain.c d5c12962d79913ef774b297006872af1fccda388f61a11d37758f9179a09551f
@@ -1825,7 +1825,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 47fa65343e46c7782a173174952c637c5621e16229ece258dc7e7a556683ca0c
-R be79b692a16f80cd3224bf9c098d5fd5
+P e736da9c18fad138c5502d354c3553373cba15358b69e44b257f60def59422e2
+R 32f00eab291c2d8cfb2d8bb909898960
 U dan
-Z 9d48ce941293959626321b38e8342e0f
+Z f672687cf39d09ecc13e261b2e491ea1

diff --git a/manifest.uuid b/manifest.uuid
index 5faf9c5ba643528d37b03e160b05acc394aca986..85b050179e1c3b72b159cfda996967502fac2386 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-e736da9c18fad138c5502d354c3553373cba15358b69e44b257f60def59422e2
\ No newline at end of file
+dbc6a9f7f67256dea96d3245e7bec145ba65d64adf322e18f1f3ac9556b4e0b6
\ No newline at end of file