diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/select.c | 16 | ||||
| -rw-r--r-- | src/sqlite.h.in | 2 |
2 files changed, 13 insertions, 5 deletions
diff --git a/src/select.c b/src/select.c index 57d0b93fb..eabbcc8c9 100644 --- a/src/select.c +++ b/src/select.c @@ -5124,15 +5124,23 @@ int sqlite3Select( SelectDest dest; Select *pSub; - /* Issue SQLITE_READ authorizations with a NULL column name for any tables that + /* Issue SQLITE_READ authorizations with a fake column name for any tables that ** are referenced but from which no values are extracted. Examples of where these ** kinds of null SQLITE_READ authorizations would occur: ** - ** SELECT count(*) FROM t1; -- SQLITE_READ t1 null - ** SELECT t1.* FROM t1, t2; -- SQLITE_READ t2 null + ** SELECT count(*) FROM t1; -- SQLITE_READ t1."" + ** SELECT t1.* FROM t1, t2; -- SQLITE_READ t2."" + ** + ** The fake column name is an empty string. It is possible for a table to + ** have a column named by the empty string, in which case there is no way to + ** distinguish between an unreferenced table and an actual reference to the + ** "" column. The original design was for the fake column name to be a NULL, + ** which would be unambiguous. But legacy authorization callbacks might + ** assume the column name is non-NULL and segfault. The use of an empty string + ** for the fake column name seems safer. */ if( pItem->colUsed==0 ){ - sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, pItem->zDatabase, 0); + sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", pItem->zDatabase); } #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) diff --git a/src/sqlite.h.in b/src/sqlite.h.in index 2761ce66d..74edcb56b 100644 --- a/src/sqlite.h.in +++ b/src/sqlite.h.in @@ -2714,7 +2714,7 @@ void sqlite3_randomness(int N, void *P); ** ^When a table is referenced by a [SELECT] but no column values are ** extracted from that table (for example in a query like ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback -** is invoked once for that table with a NULL column name. +** is invoked once for that table with a column name that is an empty string. ** ^If the action code is [SQLITE_DELETE] and the callback returns ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the ** [truncate optimization] is disabled and all rows are deleted individually. |