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Overview
Comment:Avoid passing NULL pointers to memcmp() or memcpy(), even when the "number-of-bytes" argument is passed 0.
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SHA1: 56ff72ab44288296efc99a608f7edc4346366a50
User & Date: dan 2016-12-30 14:15:56.745
Context
2016-12-30
14:25
Add a test to ensure that the app-defined pcache xFetch() method is never passed a key of zero. (check-in: 0bdbe49c6d user: drh tags: trunk)
14:15
Avoid passing NULL pointers to memcmp() or memcpy(), even when the "number-of-bytes" argument is passed 0. (check-in: 56ff72ab44 user: dan tags: trunk)
12:10
Fix a harmless compiler warning in fuzzcheck.c (check-in: 2842bc6053 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to ext/session/sqlite3session.c.
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        }
        n = sqlite3_value_bytes(pValue);
        if( z==0 && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
        nVarint = sessionVarintLen(n);
  
        if( aBuf ){
          sessionVarintPut(&aBuf[1], n);
          memcpy(&aBuf[nVarint + 1], eType==SQLITE_TEXT ? 
              sqlite3_value_text(pValue) : sqlite3_value_blob(pValue), n
          );
        }
  
        nByte = 1 + nVarint + n;
        break;
      }
    }
  }else{







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        }
        n = sqlite3_value_bytes(pValue);
        if( z==0 && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
        nVarint = sessionVarintLen(n);
  
        if( aBuf ){
          sessionVarintPut(&aBuf[1], n);
          if( n ) memcpy(&aBuf[nVarint + 1], z, n);


        }
  
        nByte = 1 + nVarint + n;
        break;
      }
    }
  }else{
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*/
static void sessionAppendBlob(
  SessionBuffer *p, 
  const u8 *aBlob, 
  int nBlob, 
  int *pRc
){
  if( 0==sessionBufferGrow(p, nBlob, pRc) ){
    memcpy(&p->aBuf[p->nBuf], aBlob, nBlob);
    p->nBuf += nBlob;
  }
}

/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is 







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*/
static void sessionAppendBlob(
  SessionBuffer *p, 
  const u8 *aBlob, 
  int nBlob, 
  int *pRc
){
  if( nBlob>0 && 0==sessionBufferGrow(p, nBlob, pRc) ){
    memcpy(&p->aBuf[p->nBuf], aBlob, nBlob);
    p->nBuf += nBlob;
  }
}

/*
** This function is a no-op if *pRc is other than SQLITE_OK when it is 
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          }
        }
        bChanged = 1;
        break;
      }

      default: {
        int nByte;
        int nHdr = 1 + sessionVarintGet(&pCsr[1], &nByte);
        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
        nAdvance = nHdr + nByte;
        if( eType==sqlite3_column_type(pStmt, i) 
         && nByte==sqlite3_column_bytes(pStmt, i) 
         && 0==memcmp(&pCsr[nHdr], sqlite3_column_blob(pStmt, i), nByte)
        ){
          break;
        }
        bChanged = 1;
      }
    }








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          }
        }
        bChanged = 1;
        break;
      }

      default: {
        int n;
        int nHdr = 1 + sessionVarintGet(&pCsr[1], &n);
        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
        nAdvance = nHdr + n;
        if( eType==sqlite3_column_type(pStmt, i) 
         && n==sqlite3_column_bytes(pStmt, i) 
         && (n==0 || 0==memcmp(&pCsr[nHdr], sqlite3_column_blob(pStmt, i), n))
        ){
          break;
        }
        bChanged = 1;
      }
    }

Changes to src/analyze.c.
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    ** a buffer overread.  */
    pSample->n = sqlite3_column_bytes(pStmt, 4);
    pSample->p = sqlite3DbMallocZero(db, pSample->n + 2);
    if( pSample->p==0 ){
      sqlite3_finalize(pStmt);
      return SQLITE_NOMEM_BKPT;
    }

    memcpy(pSample->p, sqlite3_column_blob(pStmt, 4), pSample->n);

    pIdx->nSample++;
  }
  rc = sqlite3_finalize(pStmt);
  if( rc==SQLITE_OK ) initAvgEq(pPrevIdx);
  return rc;
}








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    ** a buffer overread.  */
    pSample->n = sqlite3_column_bytes(pStmt, 4);
    pSample->p = sqlite3DbMallocZero(db, pSample->n + 2);
    if( pSample->p==0 ){
      sqlite3_finalize(pStmt);
      return SQLITE_NOMEM_BKPT;
    }
    if( pSample->n ){
      memcpy(pSample->p, sqlite3_column_blob(pStmt, 4), pSample->n);
    }
    pIdx->nSample++;
  }
  rc = sqlite3_finalize(pStmt);
  if( rc==SQLITE_OK ) initAvgEq(pPrevIdx);
  return rc;
}

Changes to src/func.c.
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  UNUSED_PARAMETER(argc);
  typeHaystack = sqlite3_value_type(argv[0]);
  typeNeedle = sqlite3_value_type(argv[1]);
  if( typeHaystack==SQLITE_NULL || typeNeedle==SQLITE_NULL ) return;
  nHaystack = sqlite3_value_bytes(argv[0]);
  nNeedle = sqlite3_value_bytes(argv[1]);

  if( typeHaystack==SQLITE_BLOB && typeNeedle==SQLITE_BLOB ){
    zHaystack = sqlite3_value_blob(argv[0]);
    zNeedle = sqlite3_value_blob(argv[1]);
    isText = 0;
  }else{
    zHaystack = sqlite3_value_text(argv[0]);
    zNeedle = sqlite3_value_text(argv[1]);
    isText = 1;
    if( zNeedle==0 ) return;
    assert( zHaystack );
  }
  while( nNeedle<=nHaystack && memcmp(zHaystack, zNeedle, nNeedle)!=0 ){
    N++;
    do{
      nHaystack--;
      zHaystack++;
    }while( isText && (zHaystack[0]&0xc0)==0x80 );
  }
  if( nNeedle>nHaystack ) N = 0;

  sqlite3_result_int(context, N);
}

/*
** Implementation of the printf() function.
*/
static void printfFunc(







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  UNUSED_PARAMETER(argc);
  typeHaystack = sqlite3_value_type(argv[0]);
  typeNeedle = sqlite3_value_type(argv[1]);
  if( typeHaystack==SQLITE_NULL || typeNeedle==SQLITE_NULL ) return;
  nHaystack = sqlite3_value_bytes(argv[0]);
  nNeedle = sqlite3_value_bytes(argv[1]);
  if( nNeedle>0 ){
    if( typeHaystack==SQLITE_BLOB && typeNeedle==SQLITE_BLOB ){
      zHaystack = sqlite3_value_blob(argv[0]);
      zNeedle = sqlite3_value_blob(argv[1]);
      isText = 0;
    }else{
      zHaystack = sqlite3_value_text(argv[0]);
      zNeedle = sqlite3_value_text(argv[1]);
      isText = 1;
      if( zNeedle==0 ) return;
      assert( zHaystack );
    }
    while( nNeedle<=nHaystack && memcmp(zHaystack, zNeedle, nNeedle)!=0 ){
      N++;
      do{
        nHaystack--;
        zHaystack++;
      }while( isText && (zHaystack[0]&0xc0)==0x80 );
    }
    if( nNeedle>nHaystack ) N = 0;
  }
  sqlite3_result_int(context, N);
}

/*
** Implementation of the printf() function.
*/
static void printfFunc(
Changes to src/main.c.
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      zOpt = &zVal[nVal+1];
    }

  }else{
    zFile = sqlite3_malloc64(nUri+2);
    if( !zFile ) return SQLITE_NOMEM_BKPT;

    memcpy(zFile, zUri, nUri);

    zFile[nUri] = '\0';
    zFile[nUri+1] = '\0';
    flags &= ~SQLITE_OPEN_URI;
  }

  *ppVfs = sqlite3_vfs_find(zVfs);
  if( *ppVfs==0 ){







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      zOpt = &zVal[nVal+1];
    }

  }else{
    zFile = sqlite3_malloc64(nUri+2);
    if( !zFile ) return SQLITE_NOMEM_BKPT;
    if( nUri ){
      memcpy(zFile, zUri, nUri);
    }
    zFile[nUri] = '\0';
    zFile[nUri+1] = '\0';
    flags &= ~SQLITE_OPEN_URI;
  }

  *ppVfs = sqlite3_vfs_find(zVfs);
  if( *ppVfs==0 ){
Changes to src/printf.c.
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void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
  assert( z!=0 || N==0 );
  assert( p->zText!=0 || p->nChar==0 || p->accError );
  assert( N>=0 );
  assert( p->accError==0 || p->nAlloc==0 );
  if( p->nChar+N >= p->nAlloc ){
    enlargeAndAppend(p,z,N);
  }else{
    assert( p->zText );
    p->nChar += N;
    memcpy(&p->zText[p->nChar-N], z, N);
  }
}

/*







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void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
  assert( z!=0 || N==0 );
  assert( p->zText!=0 || p->nChar==0 || p->accError );
  assert( N>=0 );
  assert( p->accError==0 || p->nAlloc==0 );
  if( p->nChar+N >= p->nAlloc ){
    enlargeAndAppend(p,z,N);
  }else if( N ){
    assert( p->zText );
    p->nChar += N;
    memcpy(&p->zText[p->nChar-N], z, N);
  }
}

/*