Tcl Source Code: View Ticket

Ticket UUID:	4789e18fcba7534cf2ca908eee2cca032e955c6e
Title:	signed integer overflow during obj-31.6
Type:	Patch	Version:	core-8-6-branch
Submitter:	chrstphrchvz	Created on:	2022-02-17 00:12:05
Subsystem:	13. Index Object	Assigned To:	jan.nijtmans
Priority:	5 Medium	Severity:	Minor
Status:	Closed	Last Modified:	2022-03-06 16:16:27
Resolution:	Fixed	Closed By:	jan.nijtmans
		Closed on:	2022-03-06 16:16:27
Description:	This command (equivalent to test obj-31.6) triggers signed integer overflow (undefined behavior), which the attached patch addresses: % string index {} end--0x80000000 tcl/generic/tclUtil.c:3846:15: runtime error: negation of -2147483648 cannot be represented in type 'int'; cast to an unsigned type to negate this value to itself tcl/generic/tclUtil.c:3770:26: runtime error: signed integer overflow: -1 + -2147483648 cannot be represented in type 'int'
User Comments:	jan.nijtmans added on 2022-03-06 16:16:27: Thanks! Fixed now in [7913cae186572c3d]. This problem was already fixed in Tcl 8.7, thanks to TIP #502. Your patch does nothing more than eliminate the warnings using type-casts, it doesn't change the result for 8.6, so that's OK for 8.6. chrstphrchvz added on 2022-02-17 09:52:53: Does the patch address the existing overflow concerns in `SetEndOffsetFromAny()`, or did those refer to something else (e.g. whether an overflow made sense as a useful result)?

Attachments:

obj-31.6-overflow.diff [download] added by chrstphrchvz on 2022-02-17 00:12:41. [details]