Bug 215674 - ip_compute_csum computes illegal zero checksum, should return ffff in such a case
Summary: ip_compute_csum computes illegal zero checksum, should return ffff in such a ...
Status: NEW
Alias: None
Product: Networking
Classification: Unclassified
Component: Other (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Stephen Hemminger
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-03-11 11:47 UTC by Eyal Lotem
Modified: 2022-03-11 11:47 UTC (History)
0 users

See Also:
Kernel Version: 4.14.268
Subsystem:
Regression: No
Bisected commit-id:

Attachments
Add an attachment (proposed patch, testcase, etc.)

Description Eyal Lotem 2022-03-11 11:47:49 UTC 
A 0 checksum indicates the checksum is to not be validated, and an 0xffff checksum indicates a zero result.

If the sum is computed to be 0, it should be substituted for 0xffff, to indicate the actual zero checksum.

This bug went unnoticed for a long time, because in 2^-16 of computed checksums, the incorrect result merely foregoes checksum validation, which is likely to not trigger any noticeable errors.
Note You need to log in before you can comment on or make changes to this bug.