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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference
Ticket UUID: 0eb70d77cb05bb227203136b38199c957bb32e63
Title: Invalid pointer passed to the authorizer callback
Status: Fixed Type: Code_Defect
Severity: Important Priority: Immediate
Subsystem: Unknown Resolution: Fixed
Last Modified: 2013-05-06 13:45:39
Version Found In:
User Comments:
drh added on 2013-05-06 13:03:05:

The UPDATE statement in the following code reads past the end of an array and passes an invalid pointer to the authorizer callback:

CREATE TABLE t1(a,b,c,d,e,f,g,h);
UPDATE t1 SET rowid=rowid+100;

The problem can be seen by running the script above in the sqlite3 command-line shell using valgrind. This problem has been in the code since version 2.7.6 circa 2003-01-25 and appears to have been added by check-in [45de93f913a18026a]. The problem has not been noticed before now because it is obscure and mostly harmless - unless the authorizer is used on an UPDATE statement that changes the ROWID the worst that can happen is a single read past the end of an array.

drh added on 2013-05-06 13:45:39:

An additional requirement for hitting this bug is that the number of columns in the table being updated must be a multiple of 8.