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Overview
| Comment: | Avoid buffer overreads and false OOM error reports that could be caused by corrupted sample records in the sqlite_stat4 table. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | sqlite_stat4 |
| Files: | files | file ages | folders |
| SHA1: |
9f85b6a52a0b9b1524daa6f24d85257e |
| User & Date: | dan 2013-08-16 14:09:43 |
Context
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2013-08-16
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| 14:23 | Add extra tests. No code changes. check-in: 949127d5 user: dan tags: sqlite_stat4 | |
| 14:09 | Avoid buffer overreads and false OOM error reports that could be caused by corrupted sample records in the sqlite_stat4 table. check-in: 9f85b6a5 user: dan tags: sqlite_stat4 | |
| 13:34 | Fix a potential segfault following an OOM while running ANALYZE. check-in: 01187978 user: drh tags: sqlite_stat4 | |
Changes
Changes to src/analyze.c.
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** the sqlite_stat4 table. In this case ignore stat3 data. */
nCol = pIdx->nSampleCol;
if( bStat3 && nCol>1 ) continue;
if( pIdx!=pPrevIdx ){
initAvgEq(pPrevIdx);
pPrevIdx = pIdx;
}
pSample = &pIdx->aSample[pIdx->nSample++];
decodeIntArray((char*)sqlite3_column_text(pStmt,1), nCol, pSample->anEq, 0);
decodeIntArray((char*)sqlite3_column_text(pStmt,2), nCol, pSample->anLt, 0);
decodeIntArray((char*)sqlite3_column_text(pStmt,3), nCol, pSample->anDLt,0);
pSample->n = sqlite3_column_bytes(pStmt, 4);
pSample->p = sqlite3DbMallocZero(db, pSample->n);
if( pSample->p==0 ){
sqlite3_finalize(pStmt);
return SQLITE_NOMEM;
}
memcpy(pSample->p, sqlite3_column_blob(pStmt, 4), pSample->n);
}
rc = sqlite3_finalize(pStmt);
if( rc==SQLITE_OK ) initAvgEq(pPrevIdx);
return rc;
}
/*
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** the sqlite_stat4 table. In this case ignore stat3 data. */
nCol = pIdx->nSampleCol;
if( bStat3 && nCol>1 ) continue;
if( pIdx!=pPrevIdx ){
initAvgEq(pPrevIdx);
pPrevIdx = pIdx;
}
pSample = &pIdx->aSample[pIdx->nSample];
decodeIntArray((char*)sqlite3_column_text(pStmt,1), nCol, pSample->anEq, 0);
decodeIntArray((char*)sqlite3_column_text(pStmt,2), nCol, pSample->anLt, 0);
decodeIntArray((char*)sqlite3_column_text(pStmt,3), nCol, pSample->anDLt,0);
/* Take a copy of the sample. Add two 0x00 bytes the end of the buffer.
** This is in case the sample record is corrupted. In that case, the
** sqlite3VdbeRecordCompare() may read up to two varints past the
** end of the allocated buffer before it realizes it is dealing with
** a corrupt record. Adding the two 0x00 bytes prevents this from causing
** 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;
}
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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Changes to test/analyze9.test.
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do_execsql_test 5.1 {
PRAGMA encoding = 'utf-16';
CREATE TABLE t0(v);
ANALYZE;
}
#-------------------------------------------------------------------------
# This was also crashing.
#
reset_db
do_execsql_test 6.1 {
CREATE TABLE t1(a, b);
CREATE INDEX i1 ON t1(a);
CREATE INDEX i2 ON t1(b);
INSERT INTO t1 VALUES(1, 1);
................................................................................
INSERT INTO sqlite_stat4 SELECT * FROM x1;
PRAGMA writable_schema = 0;
ANALYZE sqlite_master;
}
do_execsql_test 6.2 {
SELECT * FROM t1 WHERE a = 'abc';
}
finish_test
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do_execsql_test 5.1 {
PRAGMA encoding = 'utf-16';
CREATE TABLE t0(v);
ANALYZE;
}
#-------------------------------------------------------------------------
# This was also crashing (corrupt sqlite_stat4 table).
#
reset_db
do_execsql_test 6.1 {
CREATE TABLE t1(a, b);
CREATE INDEX i1 ON t1(a);
CREATE INDEX i2 ON t1(b);
INSERT INTO t1 VALUES(1, 1);
................................................................................
INSERT INTO sqlite_stat4 SELECT * FROM x1;
PRAGMA writable_schema = 0;
ANALYZE sqlite_master;
}
do_execsql_test 6.2 {
SELECT * FROM t1 WHERE a = 'abc';
}
#-------------------------------------------------------------------------
# The following tests experiment with adding corrupted records to the
# 'sample' column of the sqlite_stat4 table.
#
reset_db
sqlite3_db_config_lookaside db 0 0 0
do_execsql_test 7.1 {
CREATE TABLE t1(a, b);
CREATE INDEX i1 ON t1(a, b);
INSERT INTO t1 VALUES(1, 1);
INSERT INTO t1 VALUES(2, 2);
INSERT INTO t1 VALUES(3, 3);
INSERT INTO t1 VALUES(4, 4);
INSERT INTO t1 VALUES(5, 5);
ANALYZE;
UPDATE sqlite_stat4 SET sample = X'' WHERE rowid = 1;
ANALYZE sqlite_master;
}
do_execsql_test 7.2 {
UPDATE sqlite_stat4 SET sample = X'FFFF';
ANALYZE sqlite_master;
SELECT * FROM t1 WHERE a = 1;
} {1 1}
finish_test
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